Catalyst 3750 Switch Command Reference, 12.2(25)SEA
Cisco IOS Commands - aaa accounting through renew ip dhcp
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Catalyst 3750 Switch Cisco IOS Commands

Table Of Contents

Catalyst 3750 Switch Cisco IOS Commands

aaa accounting dot1x

aaa authentication dot1x

action

archive copy-sw

archive download-sw

archive tar

archive upload-sw

arp access-list

auto qos voip

boot auto-copy-sw

boot boothlpr

boot config-file

boot enable-break

boot helper

boot helper-config-file

boot manual

boot private-config-file

boot system

channel-group

channel-protocol

class

class-map

clear ip arp inspection log

clear ip arp inspection statistics

clear ip dhcp snooping database

clear ipc

clear l2protocol-tunnel counters

clear lacp

clear mac address-table

clear pagp

clear port-security

clear spanning-tree counters

clear spanning-tree detected-protocols

clear vmps statistics

clear vtp counters

cluster commander-address

cluster discovery hop-count

cluster enable

cluster holdtime

cluster member

cluster outside-interface

cluster run

cluster standby-group

cluster timer

define interface-range

delete

deny (ARP access-list configuration)

deny (MAC access-list configuration)

dot1x

dot1x default

dot1x guest-vlan

dot1x host-mode

dot1x initialize

dot1x max-reauth-req

dot1x max-req

dot1x multiple-hosts

dot1x port-control

dot1x re-authenticate

dot1x re-authentication

dot1x reauthentication

dot1x timeout

duplex

errdisable detect cause

errdisable recovery

flowcontrol

interface port-channel

interface range

interface vlan

ip access-group

ip address

ip arp inspection filter vlan

ip arp inspection limit

ip arp inspection log-buffer

ip arp inspection trust

ip arp inspection validate

ip arp inspection vlan

ip arp inspection vlan logging

ip dhcp snooping

ip dhcp snooping binding

ip dhcp snooping database

ip dhcp snooping information option

ip dhcp snooping information option allowed-untrusted

ip dhcp snooping limit rate

ip dhcp snooping trust

ip dhcp snooping verify

ip dhcp snooping vlan

ip igmp filter

ip igmp max-groups

ip igmp profile

ip igmp snooping

ip igmp snooping querier

ip igmp snooping report-suppression

ip source binding

ip ssh

ip verify source

l2protocol-tunnel

l2protocol-tunnel cos

lacp port-priority

lacp system-priority

logging event power-inline-status

logging file

mac access-group

mac access-list extended

mac address-table aging-time

mac address-table notification

mac address-table static

mac address-table static drop

macro apply

macro description

macro global

macro global description

macro name

match (access-map configuration)

match (class-map configuration)

mdix auto

mls qos

mls qos aggregate-policer

mls qos cos

mls qos dscp-mutation

mls qos map

mls qos queue-set output buffers

mls qos queue-set output threshold

mls qos rewrite ip dscp

mls qos srr-queue input bandwidth

mls qos srr-queue input buffers

mls qos srr-queue input cos-map

mls qos srr-queue input dscp-map

mls qos srr-queue input priority-queue

mls qos srr-queue input threshold

mls qos srr-queue output cos-map

mls qos srr-queue output dscp-map

mls qos trust

mls qos vlan-based

monitor session

mvr (global configuration)

mvr (interface configuration)

pagp learn-method

pagp port-priority

permit (ARP access-list configuration)

permit (MAC access-list configuration)

police

police aggregate

policy-map

port-channel load-balance

power inline

priority-queue

private-vlan

private-vlan mapping

queue-set

rcommand

reload

remote command

remote-span

renew ip dhcp snooping database


Catalyst 3750 Switch Cisco IOS Commands


aaa accounting dot1x

Use the aaa accounting dot1x global configuration command to enable authentication, authorization, and accounting (AAA) accounting and to create method lists defining specific accounting methods on a per-line or per-interface basis for 802.1x sessions. Use the no form of this command to disable 802.1x accounting.

aaa accounting dot1x {name | default} start-stop {broadcast group {name | radius | tacacs+} [group {name | radius | tacacs+} ... ] | group {name | radius | tacacs+} [group {name | radius | tacacs+} ... ]}

no aaa accounting dot1x {name | default}

Syntax Description

name

Name of a server group. This is optional when you enter it after the broadcast group and group keywords.

default

Use the accounting methods that follow as the default list for accounting services.

start-stop

Send a start accounting notice at the beginning of a process and a stop accounting notice at the end of a process. The start accounting record is sent in the background. The requested-user process begins regardless of whether or not the start accounting notice was received by the accounting server.

broadcast

Enable accounting records to be sent to multiple AAA servers and send accounting records to the first server in each group. If the first server is unavailable, the switch uses the list of backup servers to identify the first server.

group

Specify the server group to be used for accounting services. These are valid server group names:

name—Name of a server group.

radius—List of all RADIUS hosts.

tacacs+—List of all TACACS+ hosts.

The group keyword is optional when you enter it after the broadcast group and group keywords. You can enter more than optional group keyword.

radius

(Optional) Enable RADIUS authorization.

tacacs+

(Optional) Enable TACACS+ accounting.


Defaults

AAA accounting is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

This command requires access to a RADIUS server.


Note We recommend that you enter the dot1x reauthentication interface configuration command before configuring 802.1x RADIUS accounting on an interface.


Examples

This example shows how to configure 802.1x accounting:

Switch(config)# aaa accounting dot1x
Switch(config)#

Note The RADIUS authentication server must be properly configured to accept and log update or watchdog packets from the AAA client.


Related Commands

Command
Description

aaa authentication dot1x

Specifies one or more AAA methods for use on interfaces running 802.1x.

dot1x reauthentication

Sets the number of seconds between re-authentication attempts.


aaa authentication dot1x

Use the aaa authentication dot1x global configuration command on the switch stack or on a standalone switch to specify the authentication, authorization, and accounting (AAA) method to use on ports complying with IEEE 802.1x. Use the no form of this command to disable authentication.

aaa authentication dot1x {default} method1

no aaa authentication dot1x {default}

Syntax Description

default

Use the listed authentication method that follows this argument as the default method when a user logs in.

method1

Enter the group radius keywords to use the list of all RADIUS servers for authentication.



Note Though other keywords are visible in the command-line help strings, only the default and group radius keywords are supported.


Defaults

No authentication is performed.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

The method argument identifies the method that the authentication algorithm tries in the given sequence to validate the password provided by the client. The only method that is truly 802.1x-compliant is the group radius method, in which the client data is validated against a RADIUS authentication server.

If you specify group radius, you must configure the RADIUS server by entering the radius-server host global configuration command.

Use the show running-config privileged EXEC command to display the configured lists of authentication methods.

Examples

This example shows how to enable AAA and how to create an 802.1x-compliant authentication list. This authentication first tries to contact a RADIUS server. If this action returns an error, the user is not allowed access to the network.

Switch(config)# aaa new-model
Switch(config)# aaa authentication dot1x default group radius

You can verify your settings by entering the show running-config privileged EXEC command.

Related Commands

Command
Description

aaa new-model

Enables the AAA access control model. For syntax information, see the Cisco IOS Security Command Reference, Release 12.2 > Authentication, Authorization, and Accounting > Authentication Commands.

show running-config

Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


action

Use the action access map configuration command on the switch stack or on a standalone switch to set the action for the VLAN access map entry. Use the no form of this command to set the action to the default value, which is to forward.

action {drop | forward}

no action

Syntax Description

drop

Drop the packet when the specified conditions are matched.

forward

Forward the packet when the specified conditions are matched.


Defaults

The default action is to forward packets.

Command Modes

Access-map configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You enter access-map configuration mode by using the vlan access-map global configuration command.

If the action is drop, you should define the access map, including configuring any access control list (ACL) names in match clauses, before applying the map to a VLAN, or all packets could be dropped.

In access map configuration mode, use the match access map configuration command to define the match conditions for a VLAN map. Use the action command to set the action that occurs when a packet matches the conditions.

The drop and forward parameters are not used in the no form of the command.

Examples

This example shows how to identify and apply a VLAN access map vmap4 to VLANs 5 and 6 that causes the VLAN to forward an IP packet if the packet matches the conditions defined in access list al2:

Switch(config)# vlan access-map vmap4
Switch(config-access-map)# match ip address al2
Switch(config-access-map)# action forward
Switch(config-access-map)# exit
Switch(config)# vlan filter vmap4 vlan-list 5-6

You can verify your settings by entering the show vlan access-map privileged EXEC command.

Related Commands

Command
Description

access-list {deny | permit}

Configures a standard numbered ACL. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.

ip access-list

Creates a named access list. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.

mac access-list extended

Creates a named MAC address access list.

match (access-map configuration)

Defines the match conditions for a VLAN map.

show vlan access-map

Displays the VLAN access maps created on the switch.

vlan access-map

Creates a VLAN access map.


archive copy-sw

Use the archive copy-sw privileged EXEC command on the stack master to copy the running image from the flash memory on one stack member to the flash memory on one or more other stack members.

archive copy-sw [/destination-system destination-stack-member-number] [/force-reload] [leave-old-sw] [/no-set-boot] [/overwrite] [/reload] [/safe] source-stack-member-number

Syntax Description

/destination-system destination-stack-
member-number

(Optional) The number of the stack member to which to copy the running image. The range is 1 to 9.

/force-reload

(Optional) Unconditionally force a system reload after successfully downloading the software image.

/leave-old-sw

(Optional) Keep the old software version after a successful download.

/no-set-boot

(Optional) Do not alter the setting of the BOOT environment variable to point to the new software image after it is successfully downloaded.

/overwrite

(Optional) Overwrite the software image in flash memory with the downloaded one.

/reload

(Optional) Reload the system after downloading the image unless the configuration has been changed and not been saved.

/safe

(Optional) Keep the current software image; do not delete it to make room for the new software image before the new image is downloaded. The current image is deleted after the download.

source-stack-member-
number

The number of the stack member from which to copy the running image. The range is 1 to 9.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

The current software image is not overwritten with the copied image.

Both the software image and HTML files are copied.

The new image is copied to the flash: file system.

The BOOT environment variable is changed to point to the new software image on the flash: file system.

Image names are case sensitive; the image file is provided in tar format.


Note To successfully use the archive copy-sw privileged EXEC command, you must have downloaded from a TFTP server the images for both the stack member switch being added and the stack master. You use the archive download-sw privileged EXEC command to perform the download.


At least one stack member must be running the image that is to be copied to the switch that has incompatible software.

You can copy the image to more than one specific stack member by repeating the /destination-system destination-stack-member-number option in the command for each stack member to be upgraded. If you do not specify the destination-stack-member-number, the default is to copy the running image file to all stack members.

Using the /safe or /leave-old-sw option can cause the new copied image to fail if there is insufficient flash memory. If leaving the software in place would prevent the new image from fitting in flash memory due to space constraints, an error results.

If you used the /leave-old-sw option and did not overwrite the old image when you copied the new one, you can remove the old image by using the delete privileged EXEC command. For more information, see the "delete" section.

Use the /overwrite option to overwrite the image on the flash device with the copied one.

If you specify the command without the /overwrite option, the algorithm verifies that the new image is not the same as the one on the switch flash device or is not running on any stack members. If the images are the same, the copy does not occur. If the images are different, the old image is deleted, and the new one is copied.

After copying a new image, enter the reload privileged EXEC command to begin using the new image, or specify the /reload or /force-reload option in the archive copy-sw command.

You can enter one or more of these options with the source-stack-member-number option:

/destination-system destination-stack-member-number

/force-reload

/leave-old-sw

/no-set-boot

/overwrite

/reload

/safe

If you enter the source-stack-member-number option before one of the previous options, you can enter only the archive copy-sw source-stack-member-number command.

These are examples of how you can enter the archive copy-sw command:

To copy the running image from a stack member to another stack member and to overwrite the software image in the second stack member's flash memory (if it already exists) with the copied one, enter the archive copy-sw /destination destination-stack-member-number /overwrite source-stack-member-number command.

To copy the running image from a stack member to another stack member, keep the current software image, and reload the system after the image copies, enter the archive copy-sw /destination destination-stack-member-number /safe /reload source-stack-member-number command.

Examples

This example shows how to copy the running image from stack member 6 to stack member 8:

Switch# archive copy-sw /destination-system 8 6

This example shows how to copy the running image from stack member 6 to all the other stack members:

Switch# archive copy-sw 6

This example shows how to copy the running image from stack member 5 to stack member 7. If the image being copied already exists on the second stack member's flash memory, it can be overwritten with the copied one. The system reloads after the image is copied:

Switch# archive copy-sw /destination-system 7 /overwrite /force-reload 5

Related Commands

Command
Description

archive download-sw

Downloads a new image from a TFTP server to the switch.

archive tar

Creates a tar file, lists the files in a tar file, or extracts the files from a tar file.

archive upload-sw

Uploads an existing image on the switch to a server.

delete

Deletes a file or directory on the flash memory device.


archive download-sw

Use the archive download-sw privileged EXEC command on the switch stack or on a standalone switch to download a new image from a TFTP server to the switch or switch stack and to overwrite or keep the existing image.

archive download-sw {/force-reload | /imageonly | /leave-old-sw | /no-set-boot | /no-version-check | /destination-system stack-member-number | /only-system-type system-type | /overwrite | /reload | /safe} source-url

Syntax Description

/force-reload

Unconditionally force a system reload after successfully downloading the software image.

/imageonly

Download only the software image but not the HTML files associated with the embedded device manager. The HTML files for the existing version are deleted only if the existing version is being overwritten or removed.

/leave-old-sw

Keep the old software version after a successful download.

/no-set-boot

Do not alter the setting of the BOOT environment variable to point to the new software image after it is successfully downloaded.

/no-version-check

Download the software image without checking the compatibility of the stack protocol version on the image and on the switch stack.

/destination-system stack-member-number

Specify the specific stack member to be upgraded. The range is 1 to 9.

/only-system-type system-type

Specify the specific system type to be upgraded. The range is 0 to FFFFFFFF.

/overwrite

Overwrite the software image in flash memory with the downloaded one.

/reload

Reload the system after successfully downloading the image unless the configuration has been changed and not been saved.

/safe

Keep the current software image; do not delete it to make room for the new software image before the new image is downloaded. The current image is deleted after the download.

source-url

The source URL alias for a local or network file system. These options are supported:

The syntax for the local flash file system on the standalone switch or the stack master:
flash:

The syntax for the local flash file system on a stack member:
flash member number:

The syntax for the FTP: ftp:[[//username[:password]@location]/directory]/image-name.tar

The syntax for an HTTP server:
http://[[username:password]@]{hostname | host-ip}[/directory]/image-name.tar

The syntax for a secure HTTP server:
https://[[username:password]@]{hostname | host-ip}[/directory]/image-name.tar

The syntax for the Remote Copy Protocol (RCP): rcp:[[//username@location]/directory]/image-name.tar

The syntax for the TFTP:
tftp:[[//location]/directory]/image-name.tar

The image-name.tar is the software image to download and install on the switch.


Defaults

The current software image is not overwritten with the downloaded image.

Both the software image and HTML files are downloaded.

The new image is downloaded to the flash: file system.

The BOOT environment variable is changed to point to the new software image on the flash: file system.

Image names are case sensitive; the image file is provided in tar format.

Compatibility of the stack protocol version on the image to be downloaded is checked with the version on the switch stack.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.2(20)SE

The http and https keywords were added.


Usage Guidelines

The /imageonly option removes the HTML files for the existing image if the existing image is being removed or replaced. Only the Cisco IOS image (without the HTML files) is downloaded.

Using the /safe or /leave-old-sw option can cause the new image download to fail if there is insufficient flash memory. If leaving the software in place prevents the new image from fitting in flash memory due to space constraints, an error results.

If you used the /leave-old-sw option and did not overwrite the old image when you downloaded the new one, you can remove the old image by using the delete privileged EXEC command. For more information, see the "delete" section.

Use the /no-version-check option if you want to download an image that has a different stack protocol version than the one existing on the switch stack. You must use this option with the /destination-system option to specify the specific stack member to be upgraded with the image.


Note Use the /no-version-check option with care. All stack members, including the stack master, must have the same stack protocol version to be in the same switch stack. This option allows an image to be downloaded without first confirming the compatibility of its stack protocol version with the version of the switch stack.


You can upgrade more than one specific stack member by repeating the /destination-system option in the command for each stack member to be upgraded.

Use the /overwrite option to overwrite the image on the flash device with the downloaded one.

If you specify the command without the /overwrite option, the download algorithm verifies that the new image is not the same as the one on the switch flash device or is not running on any stack members. If the images are the same, the download does not occur. If the images are different, the old image is deleted, and the new one is downloaded.

After downloading a new image, enter the reload privileged EXEC command to begin using the new image, or specify the /reload or /force-reload option in the archive download-sw command.

Examples

This example shows how to download a new image from a TFTP server at 172.20.129.10 and overwrite the image on the switch:

Switch# archive download-sw /overwrite tftp://172.20.129.10/test-image.tar 

This example shows how to download only the software image from a TFTP server at 172.20.129.10 to the switch:

Switch# archive download-sw /imageonly tftp://172.20.129.10/test-image.tar 

This example shows how to keep the old software version after a successful download:

Switch# archive download-sw /leave-old-sw tftp://172.20.129.10/test-image.tar 

This example shows how to specifically upgrade stack members 6 and 8:

Switch# archive download-sw /imageonly /destination-system 6 /destination-system 8 
tftp://172.20.129.10/test-image.tar

Related Commands

Command
Description

archive copy-sw

Copies the running image from the flash memory on one stack member to the flash memory on one or more other stack members.

archive tar

Creates a tar file, lists the files in a tar file, or extracts the files from a tar file.

archive upload-sw

Uploads an existing image on the switch to a server.

delete

Deletes a file or directory on the flash memory device.


archive tar

Use the archive tar privileged EXEC command on the switch stack or on a standalone switch to create a tar file, list files in a tar file, or extract the files from a tar file.

archive tar {/create destination-url flash:/file-url} | {/table source-url} | {/xtract source-url flash:/file-url [dir/file...]}

Syntax Description

/create destination-url flash:/file-url

Create a new tar file on the local or network file system.

For destination-url, specify the destination URL alias for the local or network file system and the name of the tar file to create. These options are supported:

The syntax for the local flash filesystem:
flash:

The syntax for the FTP: ftp:[[//username[:password]@location]/directory]/tar-filename.tar

The syntax for the Remote Copy Protocol (RCP) is: rcp:[[//username@location]/directory]/tar-filename.tar

The syntax for the TFTP: tftp:[[//location]/directory]/tar-filename.tar

The tar-filename.tar is the tar file to be created.

For flash:/file-url, specify the location on the local flash file system from which the new tar file is created.

An optional list of files or directories within the source directory can be specified to write to the new tar file. If none are specified, all files and directories at this level are written to the newly created tar file.

/table source-url

Display the contents of an existing tar file to the screen.

For source-url, specify the source URL alias for the local or network file system. These options are supported:

The syntax for the local flash file system:
flash:

The syntax for the FTP:
ftp:[[//username[:password]@location]/directory]/tar-filename.tar

The syntax for the RCP: rcp:[[//username@location]/directory]/tar-filename.tar

The syntax for the TFTP: tftp:[[//location]/directory]/tar-filename.tar

The tar-filename.tar is the tar file to display.

/xtract source-url flash:/file-url [dir/file...]

Extract files from a tar file to the local file system.

For source-url, specify the source URL alias for the local file system. These options are supported:

The syntax for the local flash file system:
flash:

The syntax for the FTP: ftp:[[//username[:password]@location]/directory]/tar-filename.tar

The syntax for the RCP: rcp:[[//username@location]/directory]/tar-filename.tar

The syntax for the TFTP: tftp:[[//location]/directory]/tar-filename.tar

The tar-filename.tar is the tar file from which to extract.

For flash:/file-url [dir/file...], specify the location on the local flash file system into which the tar file is extracted. Use the dir/file... option to specify an optional list of files or directories within the tar file to be extracted. If none are specified, all files and directories are extracted.


Defaults

None

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Filenames and directory names are case sensitive.

Image names are case sensitive.

Examples

This example shows how to create a tar file. The command writes the contents of the new-configs directory on the local flash device to a file named saved.tar on the TFTP server at 172.20.10.30:

Switch# archive tar /create tftp:172.20.10.30/saved.tar flash:/new-configs

This example shows how to display the contents of the c3750-tv0-m.tar file that is in flash memory. The contents of the tar file appear on the screen:

Switch# archive tar /table flash:c3750-tv0-m.tar
info (219 bytes)
c3750-tv0-mz-121/ (directory)
c3750-tv0-mz-121/html/ (directory)
c3750-tv0-mz-121/html/foo.html (0 bytes)
c3750-tv0-mz-121/vegas-tv0-mz-121.bin (610856 bytes)
c3750-tv0-mz-121/info (219 bytes)
info.ver (219 bytes)

This example shows how to display only the c3750-tv0-mz-121/html directory and its contents:

Switch# archive tar /table flash:c3750-tv0-m.tar c3750-tv0-mz-121/html
c3750-tv0-mz-121/html/ (directory)
c3750-tv0-mz-121/html/foo.html (0 bytes)

This example shows how to extract the contents of a tar file on the TFTP server at 172.20.10.30. This command extracts just the new-configs directory into the root directory on the local flash file system. The remaining files in the saved.tar file are ignored.

Switch# archive tar /xtract tftp:/172.20.10.30/saved.tar flash:/ new-configs

Related Commands

Command
Description

archive copy-sw

Copies the running image from the flash memory on one stack member to the flash memory on one or more other stack members.

archive download-sw

Downloads a new image from a TFTP server to the switch.

archive upload-sw

Uploads an existing image on the switch to a server.


archive upload-sw

Use the archive upload-sw privileged EXEC command on the switch stack or on a standalone switch to upload an existing switch image to a server.

archive upload-sw [/source-system-num stack member number | /version version_string] destination-url

Syntax Description

/source-system-num stack member number

Specify the specific stack member containing the image that is to be uploaded.

/version version_string

(Optional) Specify the specific version string of the image to be uploaded.

destination-url

The destination URL alias for a local or network file system. These options are supported:

The syntax for the local flash file system on the standalone switch or the stack master:
flash:

The syntax for the local flash file system on a stack member:
flash member number:

The syntax for the FTP: ftp:[[//username[:password]@location]/directory]/image-name.tar

The syntax for the Remote Copy Protocol (RCP): rcp:[[//username@location]/directory]/image-name.tar

The syntax for the TFTP:
tftp:[[//location]/directory]/image-name.tar

The image-name.tar is the name of software image to be stored on the server.


Defaults

Uploads the currently running image from the flash: file system.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You must specify the /source-system-num option to use the /version option. Using these options together uploads the specified image, not the running image, of a specific stack member.

Use the upload feature only if the HTML files associated with the embedded device manager have been installed with the existing image.

The files are uploaded in this sequence: the Cisco IOS image, the HTML files, and info. After these files are uploaded, the software creates the tar file.

Image names are case sensitive.

Examples

This example shows how to upload the currently running on stack member 6 image to a TFTP server at 172.20.140.2:

Switch# archive upload-sw /source-system-num 6 tftp://172.20.140.2/test-image.tar 

Related Commands

Command
Description

archive copy-sw

Copies the running image from the flash memory on one stack member to the flash memory on one or more other stack members.

archive download-sw

Downloads a new image to the switch.

archive tar

Creates a tar file, lists the files in a tar file, or extracts the files from a tar file.


arp access-list

Use the arp access-list global configuration command on the switch stack or on a standalone switch to define an Address Resolution Protocol (ARP) access control list (ACL) or to add clauses to the end of a previously defined list. Use the no form of this command to delete the specified ARP access list.

arp access-list acl-name

no arp access-list acl-name

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

acl-name

Name of the ACL.


Defaults

No ARP access lists are defined.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

After entering the arp access-list command, you enter ARP access-list configuration mode, and these configuration commands are available:

default: returns a command to its default setting.

deny: specifies packets to reject. For more information, see the "deny (ARP access-list configuration)" section.

exit: exits ARP access-list configuration mode.

no: negates a command or returns to default settings.

permit: specifies packets to forward. For more information, see the "permit (ARP access-list configuration)" section.

Use the permit and deny access-list configuration commands to forward and to drop ARP packets based on the specified matching criteria.

When the ARP ACL is defined, you can apply it to a VLAN by using the ip arp inspection filter vlan global configuration command. ARP packets containing only IP-to-MAC address bindings are compared to the ACL. All other types of packets are bridged in the ingress VLAN without validation. If the ACL permits a packet, the switch forwards it. If the ACL denies a packet because of an explicit deny statement, the switch drops the packet. If the ACL denies a packet because of an implicit deny statement, the switch compares the packet to the list of DHCP bindings (unless the ACL is static, which means that packets are not compared to the bindings).

Examples

This example shows how to define an ARP access list and to permit both ARP requests and ARP responses from a host with an IP address of 1.1.1.1 and a MAC address of 0000.0000.abcd:

Switch(config)# arp access-list static-hosts
Switch(config-arp-nacl)# permit ip host 1.1.1.1 mac host 00001.0000.abcd
Switch(config-arp-nacl)# end

You can verify your settings by entering the show arp access-list privileged EXEC command.

Related Commands

Command
Description

deny (ARP access-list configuration)

Denies an ARP packet based on matches compared against the DHCP bindings.

ip arp inspection filter vlan

Permits ARP requests and responses from a host configured with a static IP address.

permit (ARP access-list configuration)

Permits an ARP packet based on matches compared against the DHCP bindings.

show arp access-list

Displays detailed information about ARP access lists.


auto qos voip

Use the auto qos voip interface configuration command on the switch stack or on a standalone switch to automatically configure quality of service (QoS) for voice over IP (VoIP) within a QoS domain. Use the no form of this command to return to the default setting.

auto qos voip {cisco-phone | cisco-softphone | trust}

no auto qos voip [cisco-phone | cisco-softphone | trust]

Syntax Description

cisco-phone

Identify this port as connected to a Cisco IP Phone, and automatically configure QoS for VoIP. The QoS labels of incoming packets are trusted only when the telephone is detected. This keyword is not supported on a 10-Gigabit Ethernet interface.

cisco-softphone

Identify this port as connected to a device running the Cisco SoftPhone, and automatically configure QoS for VoIP. This keyword is not supported on a 10-Gigabit Ethernet interface.

trust

Identify this port as connected to a trusted switch or router, and automatically configure QoS for VoIP. The QoS labels of incoming packets are trusted. For nonrouted ports, the CoS value of the incoming packet is trusted. For routed ports, the DSCP value of the incoming packet is trusted.


Defaults

Auto-QoS is disabled on the port.

When auto-QoS is enabled, it uses the ingress packet label to categorize traffic, to assign packet labels, and to configure the ingress and egress queues as shown in Table 2-1.

Table 2-1 Traffic Types, Packet Labels, and Queues

 
VoIP Data Traffic
VoIP Control
Traffic
Routing Protocol Traffic
STP 1 BPDU 2 Traffic
Real-Time Video Traffic
All Other Traffic

DSCP3

46

24, 26

48

56

34

-

CoS4

5

3

6

7

3

-

CoS-to-Ingress Queue Map

2, 3, 4, 5, 6, 7 (queue 2)

0, 1 (queue 1)

CoS-to-Egress Queue Map

5 (queue 1)

3, 6, 7 (queue 2)

4 (queue 3)

2
(queue 3)

0, 1 (queue 4)

1 STP = Spanning Tree Protocol

2 BPDU = bridge protocol data unit

3 DSCP = Differentiated Services Code Point

4 CoS = class of service


Table 2-2 shows the generated auto-QoS configuration for the ingress queues.

Table 2-2 Auto-QoS Configuration for the Ingress Queues

Ingress Queue
Queue Number
CoS-to-Queue Map
Queue Weight (Bandwidth)
Queue (Buffer) Size

SRR1 shared

1

0, 1

81 percent

67 percent

Priority

2

2, 3, 4, 5, 6, 7

19 percent

33 percent

1 SRR = shaped round robin. Ingress queues support shared mode only.


Table 2-3 shows the generated auto-QoS configuration for the egress queues.

Table 2-3 Auto-QoS Configuration for the Egress Queues

Egress Queue
Queue Number
CoS-to-Queue Map
Queue Weight (Bandwidth)
Queue (Buffer) Size for Gigabit-Capable Ports
Queue (Buffer) Size for 10/100 Ethernet Ports

Priority (shaped)

1

5

10 percent

16 percent

10 percent

SRR shared

2

3, 6, 7

10 percent

6 percent

10 percent

SRR shared

3

2, 4

60 percent

17 percent

26 percent

SRR shared

4

0, 1

20 percent

61 percent

54 percent


Command Modes

Interface configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced.

12.2(20)SE

The cisco-softphone keyword was added, and the generated auto-QoS configuration changed.


Usage Guidelines

Use this command to configure the QoS appropriate for VoIP traffic within the QoS domain. The QoS domain includes the switch, the interior of the network, and edge devices that can classify incoming traffic for QoS.

In releases earlier than Cisco IOS Release 12.2(20)SE, auto-QoS configures the switch only for VoIP with Cisco IP Phones on switch ports.

In Cisco IOS Release 12.2(20)SE or later, auto-QoS configures the switch for VoIP with Cisco IP Phones on switch and routed ports and for VoIP with devices running the Cisco SoftPhone application. These releases support only Cisco IP SoftPhone Version 1.3(3) or later. Connected devices must use Cisco Call Manager Version 4 or later.

To take advantage of the auto-QoS defaults, you should enable auto-QoS before you configure other QoS commands. You can fine-tune the auto-QoS configuration after you enable auto-QoS.


Note The switch applies the auto-QoS-generated commands as if the commands were entered from the command-line interface (CLI). An existing user configuration can cause the application of the generated commands to fail or to be overridden by the generated commands. These actions occur without warning. If all the generated commands are successfully applied, any user-entered configuration that was not overridden remains in the running configuration. Any user-entered configuration that was overridden can be retrieved by reloading the switch without saving the current configuration to memory. If the generated commands fail to be applied, the previous running configuration is restored.


If this is the first port on which you have enabled auto-QoS, the auto-QoS-generated global configuration commands are executed followed by the interface configuration commands. If you enable auto-QoS on another port, only the auto-QoS-generated interface configuration commands for that port are executed.

When you enable the auto-QoS feature on the first port, these automatic actions occur:

QoS is globally enabled (mls qos global configuration command), and other global configuration commands are added.

When you enter the auto qos voip cisco-phone interface configuration command on a port at the edge of the network that is connected to a Cisco IP Phone, the switch enables the trusted boundary feature. The switch uses the Cisco Discovery Protocol (CDP) to detect the presence or absence of a Cisco IP Phone. When a Cisco IP Phone is detected, the ingress classification on the port is set to trust the QoS label received in the packet. When a Cisco IP Phone is absent, the ingress classification is set to not trust the QoS label in the packet. The switch configures ingress and egress queues on the port according to the settings in Table 2-2 and Table 2-3.

When you enter the auto qos voip cisco-softphone interface configuration command on a port at the edge of the network that is connected to a device running the Cisco SoftPhone, the switch uses policing to decide whether a packet is in or out of profile and to specify the action on the packet. If the packet does not have a DSCP value of 24, 26, or 46 or is out of profile, the switch changes the DSCP value to 0. The switch configures ingress and egress queues on the port according to the settings in Table 2-2 and Table 2-3.

When you enter the auto qos voip trust interface configuration command on a port connected to the interior of the network, the switch trusts the CoS value for nonrouted ports or the DSCP value for routed ports in ingress packets (the assumption is that traffic has already been classified by other edge devices). The switch configures the ingress and egress queues on the port according to the settings in Table 2-2 and Table 2-3.

You can enable auto-QoS on static, dynamic-access, and voice VLAN access, and trunk ports. When enabling auto-QoS with a Cisco IP Phone on a routed port, you must assign a static IP address to the IP phone.


Note When a device running Cisco SoftPhone is connected to a switch or routed port, the switch supports only one Cisco SoftPhone application per port.


After auto-QoS is enabled, do not modify a policy map or aggregate policer that includes AutoQoS in its name. If you need to modify the policy map or aggregate policer, make a copy of it, and change the copied policy map or policer. To use the new policy map instead of the generated one, remove the generated policy map from the interface, and apply the new policy map.

To display the QoS configuration that is automatically generated when auto-QoS is enabled, enable debugging before you enable auto-QoS. Use the debug auto qos privileged EXEC command to enable auto-QoS debugging. For more information, see the debug auto qos command.

To disable auto-QoS on a port, use the no auto qos voip interface configuration command. Only the auto-QoS-generated interface configuration commands for this port are removed. If this is the last port on which auto-QoS is enabled and you enter the no auto qos voip command, auto-QoS is considered disabled even though the auto-QoS-generated global configuration commands remain (to avoid disrupting traffic on other ports affected by the global configuration). You can use the no mls qos global configuration command to disable the auto-QoS-generated global configuration commands. With QoS disabled, there is no concept of trusted or untrusted ports because the packets are not modified (the CoS, DSCP, and IP precedence values in the packet are not changed). Traffic is switched in pass-through mode (packets are switched without any rewrites and classified as best effort without any policing).

Examples

This example shows how to enable auto-QoS and to trust the QoS labels received in incoming packets when the switch or router connected to the port is a trusted device:

Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# auto qos voip trust

You can verify your settings by entering the show auto qos interface interface-id privileged EXEC command.

Related Commands

Command
Description

debug auto qos

Enables debugging of the auto-QoS feature.

mls qos cos

Defines the default CoS value of a port or assigns the default CoS to all incoming packets on the port.

mls qos map {cos-dscp dscp1 ... dscp8 | dscp-cos dscp-list to cos}

Defines the CoS-to-DSCP map or the DSCP-to-CoS map.

mls qos queue-set output buffers

Allocates buffers to a queue-set.

mls qos srr-queue input bandwidth

Assigns shaped round robin (SRR) weights to an ingress queue.

mls qos srr-queue input buffers

Allocates the buffers between the ingress queues.

mls qos srr-queue input cos-map

Maps CoS values to an ingress queue or maps CoS values to a queue and to a threshold ID.

mls qos srr-queue input dscp-map

Maps DSCP values to an ingress queue or maps DSCP values to a queue and to a threshold ID.

mls qos srr-queue input priority-queue

Configures the ingress priority queue and guarantees bandwidth.

mls qos srr-queue output cos-map

Maps CoS values to an egress queue or maps CoS values to a queue and to a threshold ID.

mls qos srr-queue output dscp-map

Maps DSCP values to an egress queue or maps DSCP values to a queue and to a threshold ID.

mls qos trust

Configures the port trust state.

queue-set

Maps a port to a queue-set.

show auto qos

Displays auto-QoS information.

show mls qos interface

Displays QoS information at the port level.

srr-queue bandwidth shape

Assigns the shaped weights and enables bandwidth shaping on the four egress queues mapped to a port.

srr-queue bandwidth share

Assigns the shared weights and enables bandwidth sharing on the four egress queues mapped to a port.


boot auto-copy-sw

Use the boot auto-copy-sw global configuration command from the stack master to enable the automatic upgrade (auto-upgrade) process. It automatically upgrades a switch in version-mismatch (VM) mode by copying the running software image on any stack member or by copying a tar file image in switch stack flash memory. Use the no form of this command to disable the auto-upgrade process.

boot auto-copy-sw

no boot auto-copy-sw

Syntax Description

This command has no arguments or keywords.

Defaults

Enabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

A switch in VM mode is a switch that has a different minor version number than the version on the switch stack. A switch in VM mode cannot join the switch stack as a fully functioning member. If the switch stack has an image that can be copied to a switch in VM mode, the auto-upgrade process automatically copies the image from a stack member to the switch in VM mode. The switch then exits VM mode, reboots, and joins the switch stack as a fully functioning member.

The auto-upgrade process affects only switches in VM mode. It does not affect existing stack members.

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.

show version

Displays version information for the hardware and firmware.


boot boothlpr

Use the boot boothlpr global configuration command on the switch stack or on a standalone switch to load a special Cisco IOS image, which when loaded into memory, can load a second Cisco IOS image into memory and launch it. This variable is used only for internal development and testing. Use the no form of this command to return to the default setting.

boot boothlpr filesystem:/file-url

no boot boothlpr

Syntax Description

filesystem:

Alias for a flash file system. Use flash: for the system board flash device.

/file-url

The path (directory) and name of a bootable helper image.


Defaults

No helper image is loaded.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Filenames and directory names are case sensitive.

This command changes the setting of the BOOTHLPR environment variable. For more information, see Appendix A, "Catalyst 3750 Switch Boot Loader Commands"

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot config-file

Use the boot config-file global configuration command on a standalone switch to specify the filename that Cisco IOS uses to read and write a nonvolatile copy of the system configuration. Use the no form of this command to return to the default setting.

boot config-file flash:/file-url

no boot config-file

Syntax Description

flash:/file-url

The path (directory) and name of the configuration file.


Defaults

The default configuration file is flash:config.text.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This command works properly only from a standalone switch.

Filenames and directory names are case sensitive.

This command changes the setting of the CONFIG_FILE environment variable. For more information, see Appendix A, "Catalyst 3750 Switch Boot Loader Commands."

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot enable-break

Use the boot enable-break global configuration command on a standalone switch to enable interrupting the automatic boot process. Use the no form of this command to return to the default setting.

boot enable-break

no boot enable-break

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled. The automatic boot process cannot be interrupted by pressing the Break key on the console.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This command works properly only from a standalone switch.

When you enter this command, you can interrupt the automatic boot process by pressing the Break key on the console after the flash file system is initialized.


Note Despite the setting of this command, you can interrupt the automatic boot process at any time by pressing the MODE button on the switch front panel.


This command changes the setting of the ENABLE_BREAK environment variable. For more information, see Appendix A, "Catalyst 3750 Switch Boot Loader Commands."

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot helper

Use the boot helper global configuration command on the switch stack or on a standalone switch to dynamically load files during boot loader initialization to extend or patch the functionality of the boot loader. Use the no form of this command to return to the default.

boot helper filesystem:/file-url ...

no boot helper

Syntax Description

filesystem:

Alias for a flash file system. Use flash: for the system board flash device.

/file-url

The path (directory) and a list of loadable files to dynamically load during loader initialization. Separate each image name with a semicolon.


Defaults

No helper files are loaded.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This variable is used only for internal development and testing.

Filenames and directory names are case sensitive.

This command changes the setting of the HELPER environment variable. For more information, see Appendix A, "Catalyst 3750 Switch Boot Loader Commands."

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot helper-config-file

Use the boot helper-config-file global configuration command on the switch stack or on a standalone switch to specify the name of the configuration file to be used by the Cisco IOS helper image. If this is not set, the file specified by the CONFIG_FILE environment variable is used by all versions of Cisco IOS that are loaded. Use the no form of this command to return to the default setting.

boot helper-config-file filesystem:/file-url

no boot helper-config file

Syntax Description

filesystem:

Alias for a flash file system. Use flash: for the system board flash device.

/file-url

The path (directory) and helper configuration file to load.


Defaults

No helper configuration file is specified.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This variable is used only for internal development and testing.

Filenames and directory names are case sensitive.

This command changes the setting of the HELPER_CONFIG_FILE environment variable. For more information, see Appendix A, "Catalyst 3750 Switch Boot Loader Commands."

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot manual

Use the boot manual global configuration command on a standalone switch to enable manually booting the switch during the next boot cycle. Use the no form of this command to return to the default setting.

boot manual

no boot manual

Syntax Description

This command has no arguments or keywords.

Defaults

Manual booting is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This command works properly only from a standalone switch.

The next time you reboot the system, the switch is in boot loader mode, which is shown by the switch: prompt. To boot the system, use the boot boot loader command, and specify the name of the bootable image.

This command changes the setting of the MANUAL_BOOT environment variable. For more information, see Appendix A, "Catalyst 3750 Switch Boot Loader Commands."

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot private-config-file

Use the boot private-config-file global configuration command on a standalone switch to specify the filename that Cisco IOS uses to read and write a nonvolatile copy of the private configuration. Use the no form of this command to return to the default setting.

boot private-config-file filename

no boot private-config-file

Syntax Description

filename

The name of the private configuration file.


Defaults

The default configuration file is private-config.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This command works properly only from a standalone switch.

Filenames are case sensitive.

Examples

This example shows how to specify the name of the private configuration file to be pconfig:

Switch(config)# boot private-config-file pconfig

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot system

Use the boot system global configuration command on the switch stack or on a standalone switch to specify the Cisco IOS image to load during the next boot cycle. Use the no form of this command to return to the default setting.

boot system {filesystem:/file-url ...| switch {number | all}}

no boot system

no boot system switch {number | all}

Syntax Description

filesystem:

Alias for a flash file system. Use flash: for the system board flash device.

/file-url

The path (directory) and name of a bootable image. Separate image names with a semicolon.

switch

Specify the switches on which the Cisco IOS image is loaded.

number

Specify a stack member.

all

Specify all stack members.


Defaults

The switch attempts to automatically boot the system by using information in the BOOT environment variable. If this variable is not set, the switch attempts to load and execute the first executable image it can by performing a recursive, depth-first search throughout the flash file system. In a depth-first search of a directory, each encountered subdirectory is completely searched before continuing the search in the original directory.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.2(25)SEA

The switch {number | all} keywords were added. The boot system command now works properly on switch stacks and standalone switches.


Usage Guidelines

Filenames and directory names are case sensitive.

If you enter the boot system filesystem:/file-url command on the stack master, the specified software image is loaded only on the stack master during the next boot cycle.

On the stack master, use the boot system switch number command to specify that the software image is loaded on the specified stack member during the next boot cycle. Use the boot system switch all command to specify that the software image is loaded on all the stack members during the next boot cycle.

When you enter the boot system switch number or the boot system switch all command on the stack master, the stack master checks if a software image is already on the stack member (except on the stack master). If the software image does not exist on the stack member (for example, stack member 1), an error message like this appears:

%Command to set boot system switch all xxx on switch=1 failed

If you are using the archive download-sw privileged EXEC command to maintain system images, you never need to use the boot system command. The boot system command is automatically manipulated to load the downloaded image.

This command changes the setting of the BOOT environment variable. For more information, see Appendix A, "Catalyst 3750 Switch Boot Loader Commands."

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


channel-group

Use the channel-group interface configuration command on the switch stack or on a standalone switch to assign an Ethernet port to an EtherChannel group. Use the no form of this command to remove an Ethernet port from an EtherChannel group.

channel-group channel-group-number mode {active | {auto [non-silent] | desirable [non-silent] | on} | passive}

no channel-group

Syntax Description

channel-group-number

Specify the channel group number. The range is 1 to 48.

mode

Specify the EtherChannel mode.

active

Unconditionally enable Link Aggregation Control Protocol (LACP).

Active mode places a port into a negotiating state in which the port initiates negotiations with other ports by sending LACP packets. A channel is formed with another port group in either the active or passive mode.

auto

Enable the Port Aggregation Protocol (PAgP) only if a PAgP device is detected.

Auto mode places a port into a passive negotiating state in which the port responds to PAgP packets it receives but does not start PAgP packet negotiation. A channel is formed only with another port group in desirable mode. When auto is enabled, silent operation is the default.

desirable

Unconditionally enable PAgP.

Desirable mode places a port into an active negotiating state in which the port starts negotiations with other ports by sending PAgP packets. A channel is formed with another port group in either the desirable or auto mode. When desirable is enabled, silent operation is the default.

non-silent

(Optional) Used with the auto or desirable keyword when traffic is expected from the other device.

on

Force the port to channel without PAgP or the LACP.

With the on mode, a usable EtherChannel exists only when a port group in the on mode is connected to another port group in the on mode.

passive

Enable LACP only if a LACP device is detected.

Passive mode places a port into a negotiating state in which the port responds to LACP packets it receives but does not initiate LACP packet negotiation. A channel is formed only with another port group in active mode.


Defaults

No channel groups are assigned.

No mode is configured.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

The active and passive keywords were added.

12.2(25)SE

The channel-group-number range was changed from 1 to 12 to 1 to 48.


Usage Guidelines

For Layer 2 EtherChannels, you do not have to create a port-channel interface first by using the interface port-channel global configuration command before assigning a physical port to a channel group. Instead, you can use the channel-group interface configuration command. It automatically creates the port-channel interface when the channel group gets its first physical port if the logical interface is not already created. If you create the port-channel interface first, the channel-group-number can be the same as the port-channel-number, or you can use a new number. If you use a new number, the channel-group command dynamically creates a new port channel.

You do not have to disable the IP address that is assigned to a physical port that is part of a channel group, but we strongly recommend that you do so.

You create Layer 3 port channels by using the interface port-channel command followed by the no switchport interface configuration command. You should manually configure the port-channel logical interface before putting the interface into the channel group.

After you configure an EtherChannel, configuration changes that you make on the port-channel interface apply to all the physical ports assigned to the port-channel interface. Configuration changes applied to the physical port affect only the port where you apply the configuration. To change the parameters of all ports in an EtherChannel, apply configuration commands to the port-channel interface, for example, spanning-tree commands or commands to configure a Layer 2 EtherChannel as a trunk.

If you do not specify non-silent with the auto or desirable mode, silent is assumed. The silent mode is used when the switch is connected to a device that is not PAgP-capable and seldom, if ever, sends packets. A example of a silent partner is a file server or a packet analyzer that is not generating traffic. In this case, running PAgP on a physical port prevents that port from ever becoming operational. However, it allows PAgP to operate, to attach the port to a channel group, and to use the port for transmission. Both ends of the link cannot be set to silent.

With the on mode, a usable EtherChannel exists only when a port group in the on mode is connected to another port group in the on mode. The on keyword is the only setting that is supported when the EtherChannel members are from different switches in the switch stack (cross-stack EtherChannel).


Caution You should exercise care when setting the mode to on (manual configuration). All ports configured in the on mode are bundled in the same group and are forced to have similar characteristics. If the group is misconfigured, packet loss or spanning-tree loops might occur.

A cross-stack EtherChannel supports up to two 10-Gigabit Ethernet interfaces.

Do not configure an EtherChannel in both the PAgP and LACP modes. EtherChannel groups running PAgP and LACP can coexist on the same switch or on different switches in the stack (but not in a cross-stack configuration). Individual EtherChannel groups can run either PAgP or LACP, but they cannot interoperate.

If you set the protocol by using the channel-protocol interface configuration command, the setting is not overridden by the channel-group interface configuration command.

Do not configure a port that is an active or a not-yet-active member of an EtherChannel as an 802.1x port. If you try to enable 802.1x on an EtherChannel port, an error message appears, and 802.1x is not enabled.


Note If 802.1x is enabled on a not-yet active port of an EtherChannel in software releases earlier than Cisco IOS Release 12.2(18)SE, the port does not join the EtherChannel.


Do not configure a secure port as part of an EtherChannel or an EtherChannel port as a secure port.

For a complete list of configuration guidelines, see the "Configuring EtherChannels" chapter in the software configuration guide for this release.


Caution Do not enable Layer 3 addresses on the physical EtherChannel ports. Do not assign bridge groups on the physical EtherChannel ports because it creates loops.

Examples

This example shows how to configure an EtherChannel on a single switch in the stack. It assigns two static-access ports in VLAN 10 to channel 5 with the PAgP mode desirable:

Switch# configure terminal 
Switch(config)# interface range gigabitethernet2/0/1 -2 
Switch(config-if-range)# switchport mode access
Switch(config-if-range)# switchport access vlan 10
Switch(config-if-range)# channel-group 5 mode desirable 
Switch(config-if-range)# end 

This example shows how to configure an EtherChannel on a single switch in the stack. It assigns two static-access ports in VLAN 10 to channel 5 with the LACP mode active:

Switch# configure terminal 
Switch(config)# interface range gigabitethernet2/0/1 -2 
Switch(config-if-range)# switchport mode access
Switch(config-if-range)# switchport access vlan 10
Switch(config-if-range)# channel-group 5 mode active 
Switch(config-if-range)# end 

This example shows how to configure a cross-stack EtherChannel. It assigns two ports on stack member 2 and one port on stack member 3 as static-access ports in VLAN 10 to channel 5 with the PAgP and LACP modes disabled (on):

Switch# configure terminal 
Switch(config)# interface range gigabitethernet2/0/4 -5 
Switch(config-if-range)# switchport mode access
Switch(config-if-range)# switchport access vlan 10
Switch(config-if-range)# channel-group 5 mode on 
Switch(config-if-range)# exit
Switch(config)# interface gigabitethernet3/0/3 
Switch(config-if)# switchport mode access
Switch(config-if)# switchport access vlan 10
Switch(config-if)# channel-group 5 mode on 
Switch(config-if)# exit

You can verify your settings by entering the show running-config privileged EXEC command.

Related Commands

Command
Description

channel-protocol

Restricts the protocol used on a port to manage channeling.

interface port-channel

Accesses or creates the port channel.

show etherchannel

Displays EtherChannel information for a channel.

show lacp

Displays LACP channel-group information.

show pagp

Displays PAgP channel-group information.

show running-config

Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


channel-protocol

Use the channel-protocol interface configuration command on the switch stack or on a standalone switch to restrict the protocol used on a port to manage channeling. Use the no form of this command to return to the default setting.

channel-protocol {lacp | pagp}

no channel-protocol

Syntax Description

lacp

Configure an EtherChannel with the Link Aggregation Control Protocol (LACP).

pagp

Configure an EtherChannel with the Port Aggregation Protocol (PAgP).


Defaults

No protocol is assigned to the EtherChannel.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced.


Usage Guidelines

Use the channel-protocol command only to restrict a channel to LACP or PAgP. If you set the protocol by using the channel-protocol command, the setting is not overridden by the channel-group interface configuration command.

You must use the channel-group interface configuration command to configure the EtherChannel parameters. The channel-group command also can set the mode for the EtherChannel.

You cannot enable both the PAgP and LACP modes on an EtherChannel group.

PAgP and LACP are not compatible; both ends of a channel must use the same protocol.

Examples

This example shows how to specify LACP as the protocol that manages the EtherChannel:

Switch(config-if)# channel-protocol lacp

You can verify your settings by entering the show etherchannel [channel-group-number] protocol privileged EXEC command.

Related Commands

Command
Description

channel-group

Assigns an Ethernet port to an EtherChannel group.

show etherchannel protocol

Displays protocol information the EtherChannel.


class

Use the class policy-map configuration command on the switch stack or on a standalone switch to define a traffic classification match criteria (through the police, set, and trust policy-map class configuration commands) for the specified class-map name. Use the no form of this command to delete an existing class map.

class class-map-name

no class class-map-name

Syntax Description

class-map-name

Name of the class map.


Defaults

No policy map class-maps are defined.

Command Modes

Policy-map configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Before using the class command, you must use the policy-map global configuration command to identify the policy map and to enter policy-map configuration mode. After specifying a policy map, you can configure a policy for new classes or modify a policy for any existing classes in that policy map. You attach the policy map to a port by using the service-policy interface configuration command.

After entering the class command, you enter policy-map class configuration mode, and these configuration commands are available:

exit: exits policy-map class configuration mode and returns to policy-map configuration mode.

no: returns a command to its default setting.

police: defines a policer or aggregate policer for the classified traffic. The policer specifies the bandwidth limitations and the action to take when the limits are exceeded. For more information, see the police and police aggregate policy-map class commands.

set: specifies a value to be assigned to the classified traffic. For more information, see the set command.

trust: defines a trust state for traffic classified with the class or the class-map command. For more information, see the trust command.

To return to policy-map configuration mode, use the exit command. To return to privileged EXEC mode, use the end command.

The class command performs the same function as the class-map global configuration command. Use the class command when a new classification, which is not shared with any other ports, is needed. Use the class-map command when the map is shared among many ports.

Examples

This example shows how to create a policy map called policy1. When attached to the ingress direction, it matches all the incoming traffic defined in class1, sets the IP Differentiated Services Code Point (DSCP) to 10, and polices the traffic at an average rate of 1 Mbps and bursts at 20 KB. Traffic exceeding the profile is marked down to a DSCP value obtained from the policed-DSCP map and then sent.

Switch(config)# policy-map policy1
Switch(config-pmap)# class class1
Switch(config-pmap-c)# set dscp 10
Switch(config-pmap-c)# police 1000000 20000 exceed-action policed-dscp-transmit
Switch(config-pmap-c)# exit

You can verify your settings by entering the show policy-map privileged EXEC command.

Related Commands

Command
Description

class-map

Creates a class map to be used for matching packets to the class whose name you specify.

police

Defines a policer for classified traffic.

policy-map

Creates or modifies a policy map that can be attached to multiple ports to specify a service policy.

set

Classifies IP traffic by setting a DSCP or IP-precedence value in the packet.

show policy-map

Displays quality of service (QoS) policy maps.

trust

Defines a trust state for the traffic classified through the class policy-map configuration command or the class-map global configuration command.


class-map

Use the class-map global configuration command on the switch stack or on a standalone switch to create a class map to be used for matching packets to the class whose name you specify and to enter class-map configuration mode. Use the no form of this command to delete an existing class map and to return to global configuration mode.

class-map [match-all | match-any] class-map-name

no class-map [match-all | match-any] class-map-name

Syntax Description

match-all

(Optional) Perform a logical-AND of all matching statements under this class map. All criteria in the class map must be matched.

match-any

(Optional) Perform a logical-OR of the matching statements under this class map. One or more criteria must be matched.

class-map-name

Name of the class map.


Defaults

No class maps are defined.

If neither the match-all or match-any keyword is specified, the default is match-all.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Use this command to specify the name of the class for which you want to create or modify class-map match criteria and to enter class-map configuration mode.

The class-map command and its subcommands are used to define packet classification, marking, and aggregate policing as part of a globally named service policy applied on a per-port basis.

After you are in quality of service (QoS) class-map configuration mode, these configuration commands are available:

description: describes the class map (up to 200 characters). The show class-map privileged EXEC command displays the description and the name of the class-map.

exit: exits from QoS class-map configuration mode.

match: configures classification criteria. For more information, see the match (class-map configuration) command.

no: removes a match statement from a class map.

rename: renames the current class map. If you rename a class map with a name that is already used, the message A class-map with this name already exists appears.

To define packet classification on a physical-port basis, only one match command per class map is supported. In this situation, the match-all and match-any keywords are equivalent.

Only one access control list (ACL) can be configured in a class map. The ACL can have multiple access control entries (ACEs).

Examples

This example shows how to configure the class map called class1 with one match criterion, which is an access list called 103:

Switch(config)# access-list 103 permit any any dscp 10
Switch(config)# class-map class1
Switch(config-cmap)# match access-group 103
Switch(config-cmap)# exit

This example shows how to delete the class map class1:

Switch(config)# no class-map class1

You can verify your settings by entering the show class-map privileged EXEC command.

Related Commands

Command
Description

class

Defines a traffic classification match criteria (through the police, set, and trust policy-map class configuration commands) for the specified class-map name.

match (class-map configuration)

Defines the match criteria to classify traffic.

policy-map

Creates or modifies a policy map that can be attached to multiple ports to specify a service policy.

show class-map

Displays QoS class maps.


clear ip arp inspection log

Use the clear ip arp inspection log privileged EXEC command on the switch stack or on a standalone switch to clear the dynamic Address Resolution Protocol (ARP) inspection log buffer.

clear ip arp inspection log

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Examples

This example shows how to clear the contents of the log buffer:

Switch# clear ip arp inspection log

You can verify that the log was cleared by entering the show ip arp inspection log privileged command.

Related Commands

Command
Description

arp access-list

Defines an ARP access control list (ACL).

ip arp inspection log-buffer

Configures the dynamic ARP inspection logging buffer.

ip arp inspection vlan logging

Controls the type of packets that are logged per VLAN.

show ip arp inspection log

Displays the configuration and contents of the dynamic ARP inspection log buffer.


clear ip arp inspection statistics

Use the clear ip arp inspection statistics privileged EXEC command on the switch stack or on a standalone switch to clear the dynamic Address Resolution Protocol (ARP) inspection statistics.

clear ip arp inspection statistics [vlan vlan-range]

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

vlan vlan-range

(Optional) Clear statistics for the specified VLAN or VLANs.

You can specify a single VLAN identified by VLAN ID number, a range of VLANs separated by a hyphen, or a series of VLANs separated by a comma. The range is 1 to 4094.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Examples

This example shows how to clear the statistics for VLAN 1:

Switch# clear ip arp inspection statistics vlan 1

You can verify that the statistics were deleted by entering the show ip arp inspection statistics vlan 1 privileged EXEC command.

Related Commands

Command
Description

show ip arp inspection statistics

Displays statistics for forwarded, dropped, MAC validation failure, and IP validation failure packets for all VLANs or the specified VLAN.


clear ip dhcp snooping database

Use the clear ip dhcp snooping database privileged EXEC command on the switch stack or on a standalone switch to clear the DHCP binding database agent statistics.

clear ip dhcp snooping database statistics

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

statistics

Clear the DHCP snooping binding database agent statistics.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

When you enter the clear ip dhcp snooping database statistics command, the switch does not update the entries in the binding database and in the binding file before clearing the statistics.

Examples

This example shows how to clear the DHCP snooping binding database agent statistics:

Switch# clear ip dhcp snooping database statistics 

You can verify that the statistics were cleared by entering the show ip dhcp snooping database privileged EXEC command.

Related Commands

Command
Description

ip dhcp snooping

Enables DHCP snooping on a VLAN.

ip dhcp snooping database

Configures the DHCP snooping binding database agent or the binding file.

show ip dhcp snooping binding

Displays the status of DHCP snooping database agent.


clear ipc

Use the clear ipc privileged EXEC command on the switch stack or on a standalone switch to clear Interprocess Communications Protocol (IPC) statistics.

clear ipc {queue-statistics | statistics}

Syntax Description

queue-statistics

Clear the IPC queue statistics.

statistics

Clear the IPC statistics.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(18)SE

This command was introduced.


Usage Guidelines

You can clear all statistics by using the clear ipc statistics command, or you can clear only the queue statistics by using the clear ipc queue-statistics command.

Examples

This example shows how to clear all statistics:

Switch# clear ipc statistics

This example shows how to clear only the queue statistics:

Switch# clear ipc queue-statistics

You can verify that the statistics were deleted by entering the show ipc rpc or the show ipc session privileged EXEC command.

Related Commands

Command
Description

show ipc {rpc | session}

Displays the IPC multicast routing statistics.


clear l2protocol-tunnel counters

Use the clear l2protocol-tunnel counters privileged EXEC command on the switch stack or on a standalone switch to clear the protocol counters in protocol tunnel ports.

clear l2protocol-tunnel counters [interface-id]

Syntax Description

interface-id

(Optional) Specify interface (physical interface or port channel) for which protocol counters are to be cleared.


Defaults

This command has no defaults.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(25)SE

This command was introduced.


Usage Guidelines

Use this command to clear protocol tunnel counters on the switch or on the specified interface.

Examples

This example shows how to clear Layer 2 protocol tunnel counters on an interface:

Switch# clear l2protocol-tunnel counters gigabitethernet0/3

Related Commands

Command
Description

show l2protocol-tunnel

Displays information about ports configured for Layer 2 protocol tunneling.


clear lacp

Use the clear lacp privileged EXEC command on the switch stack or on a standalone switch to clear Link Aggregation Control Protocol (LACP) channel-group counters.

clear lacp {channel-group-number counters | counters}

Syntax Description

channel-group-number

(Optional) Channel group number. The range is 1 to 48.

counters

Clear traffic counters.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(14)EA1

This command was introduced.

12.2(25)SE

The channel-group-number range was changed from 1 to 12 to 1 to 48.


Usage Guidelines

You can clear all counters by using the clear lacp counters command, or you can clear only the counters for the specified channel group by using the clear lacp channel-group-number counters command.

Examples

This example shows how to clear all channel-group information:

Switch# clear lacp counters

This example shows how to clear LACP traffic counters for group 4:

Switch# clear lacp 4 counters

You can verify that the information was deleted by entering the show lacp counters or the show lacp 4 counters privileged EXEC command.

Related Commands

Command
Description

show lacp

Displays LACP channel-group information.


clear mac address-table

Use the clear mac address-table privileged EXEC command on the switch stack or on a standalone switch to delete from the MAC address table a specific dynamic address, all dynamic addresses on a particular interface, all dynamic addresses on stack members, or all dynamic addresses on a particular VLAN. This command also clears the MAC address notification global counters.

clear mac address-table {dynamic [address mac-addr | interface interface-id | vlan vlan-id] | notification}


Note Beginning with Cisco IOS Release 12.1(19)EA1, the clear mac address-table command replaces the clear mac- address-table command (with the hyphen).


Syntax Description

dynamic

Delete all dynamic MAC addresses.

dynamic address mac-addr

(Optional) Delete the specified dynamic MAC address.

dynamic interface interface-id

(Optional) Delete all dynamic MAC addresses on the specified physical port or port channel.

dynamic vlan vlan-id

(Optional) Delete all dynamic MAC addresses for the specified VLAN. The range is 1 to 4096.

notification

Clear the notifications in the history table and reset the counters.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(19)EA1

The clear mac-address-table command was replaced by the clear mac address-table command.


Examples

This example shows how to remove a specific MAC address from the dynamic address table:

Switch# clear mac address-table dynamic address 0008.0070.0007

You can verify that the information was deleted by entering the show mac address-table privileged EXEC command.

Related Commands

Command
Description

mac address-table notification

Enables the MAC address notification feature.

show mac address-table

Displays the MAC address table static and dynamic entries.

show mac address-table notification

Displays the MAC address notification settings for all interfaces or the specified interface.

snmp trap mac-notification

Enables the Simple Network Management Protocol (SNMP) MAC address notification trap on a specific interface.


clear pagp

Use the clear pagp privileged EXEC command on the switch stack or on a standalone switch to clear Port Aggregation Protocol (PAgP) channel-group information.

clear pagp {channel-group-number counters | counters}

Syntax Description

channel-group-number

(Optional) Channel group number. The range is 1 to 48.

counters

Clear traffic counters.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.2(25)SE

The channel-group-number range was changed from 1 to 12 to 1 to 48.


Usage Guidelines

You can clear all counters by using the clear pagp counters command, or you can clear only the counters for the specified channel group by using the clear pagp channel-group-number counters command.

Examples

This example shows how to clear all channel-group information:

Switch# clear pagp counters

This example shows how to clear PAgP traffic counters for group 10:

Switch# clear pagp 10 counters

You can verify that information was deleted by entering the show pagp privileged EXEC command.

Related Commands

Command
Description

show pagp

Displays PAgP channel-group information.


clear port-security

Use the clear port-security privileged EXEC command on the switch stack or on a standalone switch to delete from the MAC address table all secure addresses or all secure addresses of a specific type (configured, dynamic, or sticky) on the switch or on an interface.

clear port-security {all | configured | dynamic | sticky} [[address mac-addr | interface interface-id] [vlan vlan-id]]

Syntax Description

all

Delete all secure MAC addresses.

configured

Delete configured secure MAC addresses.

dynamic

Delete secure MAC addresses auto-learned by hardware.

sticky

Delete secure MAC addresses, either auto-learned or configured.

address mac-addr

(Optional) Delete the specified dynamic secure MAC address.

interface interface-id

(Optional) Delete all the dynamic secure MAC addresses on the specified physical port or VLAN.

vlan vlan-id

(Optional) VLAN ID of the VLAN on which this address should be cleared.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(25)SEA

This command was introduced.


Examples

This example shows how to clear all secure addresses from the MAC address table:

Switch# clear port-security all

This example shows how to remove a specific configured secure address from the MAC address table:

Switch# clear port-security configured address 0008.0070.0007

This example shows how to remove all the dynamic secure addresses learned on a specific interface:

Switch# clear port-security dynamic interface gigabitethernet1/0/1

This example shows how to remove all the dynamic secure addresses from the address table:

Switch# clear port-security dynamic

You can verify that the information was deleted by entering the show port-security privileged EXEC command.

Related Commands

Command
Description

switchport port-security

Enables port security on an interface.

switchport port-security mac-address mac-address

Configures secure MAC addresses.

switchport port-security maximum value

Configures a maximum number of secure MAC addresses on a secure interface.

show port-security

Displays the port security settings defined for an interface or for the switch.


clear spanning-tree counters

Use the clear spanning-tree counters privileged EXEC command on the switch stack or on a standalone switch to clear the spanning-tree counters.

clear spanning-tree counters [interface interface-id]

Syntax Description

interface interface-id

(Optional) Clear all spanning-tree counters on the specified interface. Valid interfaces include physical ports, VLANs, and port channels. The VLAN range is 1 to 4094. The port-channel range is 1 to 48.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(14)EA1

This command was introduced.


Usage Guidelines

If the interface-id is not specified, spanning-tree counters are cleared for all interfaces.

Examples

This example shows how to clear spanning-tree counters for all interfaces:

Switch# clear spanning-tree counters

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree state information.


clear spanning-tree detected-protocols

Use the clear spanning-tree detected-protocols privileged EXEC command on the switch stack or on a standalone switch to restart the protocol migration process (force the renegotiation with neighboring switches) on all interfaces or on the specified interface.

clear spanning-tree detected-protocols [interface interface-id]

Syntax Description

interface interface-id

(Optional) Restart the protocol migration process on the specified interface. Valid interfaces include physical ports, VLANs, and port channels. The VLAN range is 1 to 4094. The port-channel range is 1 to 48.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(14)EA1

This command was introduced.


Usage Guidelines

A switch running the rapid per-VLAN spanning-tree plus (rapid-PVST+) protocol or the Multiple Spanning Tree Protocol (MSTP) supports a built-in protocol migration mechanism that enables it to interoperate with legacy 802.1D switches. If a rapid-PVST+ switch or an MSTP switch receives a legacy 802.1D configuration bridge protocol data unit (BPDU) with the protocol version set to 0, it sends only 802.1D BPDUs on that port. A multiple spanning-tree (MST) switch can also detect that a port is at the boundary of a region when it receives a legacy BPDU, an MST BPDU (Version 3) associated with a different region, or a rapid spanning-tree (RST) BPDU (Version 2).

However, the switch does not automatically revert to the rapid-PVST+ or the MSTP mode if it no longer receives 802.1D BPDUs because it cannot learn whether the legacy switch has been removed from the link unless the legacy switch is the designated switch. Use the clear spanning-tree detected-protocols command in this situation.

Examples

This example shows how to restart the protocol migration process on a port:

Switch# clear spanning-tree detected-protocols interface gigabitethernet2/0/1

Related Commands

Command
Description

show spanning-tree

Displays spanning-tree state information.

spanning-tree link-type

Overrides the default link-type setting and enables rapid spanning-tree transitions to the forwarding state.


clear vmps statistics

Use the clear vmps statistics privileged EXEC command on the switch stack or on a standalone switch to clear the statistics maintained by the VLAN Query Protocol (VQP) client.

clear vmps statistics

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Examples

This example shows how to clear VLAN Membership Policy Server (VMPS) statistics:

Switch# clear vmps statistics

You can verify that information was deleted by entering the show vmps statistics privileged EXEC command.

Related Commands

Command
Description

show vmps

Displays the VQP version, reconfirmation interval, retry count, VMPS IP addresses, and the current and primary servers.


clear vtp counters

Use the clear vtp counters privileged EXEC command on the switch stack or on a standalone switch to clear the VLAN Trunking Protocol (VTP) and pruning counters.

clear vtp counters

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Examples

This example shows how to clear the VTP counters:

Switch# clear vtp counters

You can verify that information was deleted by entering the show vtp counters privileged EXEC command.

Related Commands

Command
Description

show vtp

Displays general information about the VTP management domain, status, and counters.


cluster commander-address

You do not need to enter this command from the switch stack or from a standalone cluster member switch. The cluster command switch automatically provides its MAC address to cluster member switches when these switches join the cluster. The cluster member switch adds this information and other cluster information to its running configuration file. Use the no form of this global configuration command from the cluster member switch console port to remove the switch from a cluster only during debugging or recovery procedures.

cluster commander-address mac-address [member number name name]

no cluster commander-address

Syntax Description

mac-address

MAC address of the cluster command switch.

member number

(Optional) Number of a configured cluster member switch. The range is 0 to 15.

name name

(Optional) Name of the configured cluster up to 31 characters.


Defaults

The switch is not a member of any cluster.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This command is available only on the cluster command switch stack or the cluster command switch.

A cluster member can have only one cluster command switch.

The cluster member switch retains the identity of the cluster command switch during a system reload by using the mac-address parameter.

You can enter the no form on a cluster member switch to remove it from the cluster during debugging or recovery procedures. You would normally use this command from the cluster member switch console port only when the member has lost communication with the cluster command switch. With normal switch configuration, we recommend that you remove cluster member switches only by entering the no cluster member n global configuration command on the cluster command switch.

When a standby cluster command switch becomes active (becomes the cluster command switch), it removes the cluster commander address line from its configuration.

Examples

This is partial sample output from the running configuration of a cluster member.

Switch(config)# show running-configuration

<output truncated>

cluster commander-address 00e0.9bc0.a500 member 4 name my_cluster

<output truncated>

This example shows how to remove a member from the cluster by using the cluster member console.

Switch # configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Switch(config)# no cluster commander-address

You can verify your settings by entering the show cluster privileged EXEC command.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster discovery hop-count

Use the cluster discovery hop-count global configuration command on the switch stack or on the a cluster command switch on the cluster command switch to set the hop-count limit for extended discovery of candidate switches. Use the no form of this command to return to the default setting.

cluster discovery hop-count number

no cluster discovery hop-count

Syntax Description

number

Number of hops from the cluster edge that the cluster command switch limits the discovery of candidates. The range is 1 to 7.


Defaults

The hop count is set to 3.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This command is available only on the cluster command switch stack or cluster command switch. This command does not operate on cluster member switches.

If the hop count is set to 1, it disables extended discovery. The cluster command switch discovers only candidates that are one hop from the edge of the cluster. The edge of the cluster is the point between the last discovered cluster member switch and the first discovered candidate switch.

Examples

This example shows how to set hop count limit to 4. This command is executed on the cluster command switch.

Switch(config)# cluster discovery hop-count 4

You can verify your setting by entering the show cluster privileged EXEC command.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show cluster candidates

Displays a list of candidate switches.


cluster enable

Use the cluster enable global configuration command on a command-capable switch or switch stack to enable it as the cluster command switch, assign a cluster name, and to optionally assign a member number to it. Use the no form of the command to remove all members and to make the cluster command switch a candidate switch.

cluster enable name [command-switch-member-number]

no cluster enable

Syntax Description

name

Name of the cluster up to 31 characters. Valid characters include only alphanumerics, dashes, and underscores.

command-switch-member-number

(Optional) Assign a member number to the cluster command switch of the cluster. The range is 0 to 15.


Defaults

The switch is not a cluster command switch.

No cluster name is defined.

The member number is 0 when the switch is the cluster command switch.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Enter this command on any command-capable switch that is not part of any cluster. This command fails if a device is already configured as a member of the cluster.

You must name the cluster when you enable the cluster command switch. If the switch is already configured as the cluster command switch, this command changes the cluster name if it is different from the previous cluster name.

Examples

This example shows how to enable the cluster command switch, name the cluster, and set the cluster command switch member number to 4.

Switch(config)# cluster enable Engineering-IDF4 4

You can verify your setting by entering the show cluster privileged EXEC command on the cluster command switch.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster holdtime

Use the cluster holdtime global configuration command on the switch stack or on the a cluster command switch to set the duration in seconds before a switch (either the command or cluster member switch) declares the other switch down after not receiving heartbeat messages. Use the no form of this command to set the duration to the default value.

cluster holdtime holdtime-in-secs

no cluster holdtime

Syntax Description

holdtime-in-secs

Duration in seconds before a switch (either a command or cluster member switch) declares the other switch down. The range is 1 to 300 seconds.


Defaults

The default holdtime is 80 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Enter this command with the cluster timer global configuration command only on the cluster command switch. The cluster command switch propagates the values to all its cluster members so that the setting is consistent among all switches in the cluster.

The holdtime is typically set as a multiple of the interval timer (cluster timer). For example, it takes (holdtime-in-secs divided by the interval-in-secs) number of heartbeat messages to be missed in a row to declare a switch down.

Examples

This example shows how to change the interval timer and the duration on the cluster command switch.

Switch(config)# cluster timer 3
Switch(config)# cluster holdtime 30

You can verify your settings by entering the show cluster privileged EXEC command.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster member

Use the cluster member global configuration command on the cluster command switch to add candidates to a cluster. Use the no form of the command to remove members from the cluster.

cluster member [n] mac-address H.H.H [password enable-password] [vlan vlan-id]

no cluster member n

Syntax Description

n

The number that identifies a cluster member. The range is 0 to 15.

mac-address H.H.H

MAC address of the cluster member switch in hexadecimal format.

password enable-password

Enable password of the candidate switch. The password is not required if there is no password on the candidate switch.

vlan vlan-id

(Optional) VLAN ID through which the candidate is added to the cluster by the cluster command switch. The range is 1 to 4094.


Defaults

A newly enabled cluster command switch has no associated cluster members.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Enter this command only on the cluster command switch to add a candidate to or remove a member from the cluster. If you enter this command on a switch other than the cluster command switch, the switch rejects the command and displays an error message.

You must enter a member number to remove a switch from the cluster. However, you do not need to enter a member number to add a switch to the cluster. The cluster command switch selects the next available member number and assigns it to the switch that is joining the cluster.

You must enter the enable password of the candidate switch for authentication when it joins the cluster. The password is not saved in the running or startup configuration. After a candidate switch becomes a member of the cluster, its password becomes the same as the cluster command-switch password.

If a switch does not have a configured hostname, the cluster command switch appends a member number to the cluster command-switch hostname and assigns it to the cluster member switch.

If you do not specify a VLAN ID, the cluster command switch automatically chooses a VLAN and adds the candidate to the cluster.

Examples

This example shows how to add a switch as member 2 with MAC address 00E0.1E00.2222 and the password key to a cluster. The cluster command switch adds the candidate to the cluster through VLAN 3.

Switch(config)# cluster member 2 mac-address 00E0.1E00.2222 password key vlan 3

This example shows how to add a switch with MAC address 00E0.1E00.3333 to the cluster. This switch does not have a password. The cluster command switch selects the next available member number and assigns it to the switch that is joining the cluster.

Switch(config)# cluster member mac-address 00E0.1E00.3333

You can verify your settings by entering the show cluster members privileged EXEC command on the cluster command switch.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show cluster candidates

Displays a list of candidate switches.

show cluster members

Displays information about the cluster members.


cluster outside-interface

Use the cluster outside-interface global configuration command on the switch stack or on the a cluster command switch to configure the outside interface for cluster Network Address Translation (NAT) so that a member without an IP address can communicate with devices outside the cluster. Use the no form of this command to return to the default setting.

cluster outside-interface interface-id

no cluster outside-interface

Syntax Description

interface-id

Interface to serve as the outside interface. Valid interfaces include physical interfaces, port-channels, or VLANs. The port-channel range is 1 to 48. The VLAN range is 1 to 4094.


Defaults

The default outside interface is automatically selected by the cluster command switch.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Enter this command only on the cluster command switch. If you enter this command on a cluster member switch, an error message appears.

Examples

This example shows how to set the outside interface to VLAN 1:

Switch(config)# cluster outside-interface vlan 1

You can verify your setting by entering the show running-config privileged EXEC command.

Related Commands

Command
Description

show running-config

Displays the current operating configuration. For syntax information, select the Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


cluster run

Use the cluster run global configuration command to enable clustering on a switch. Use the no form of this command to disable clustering on a switch.

cluster run

no cluster run

Syntax Description

This command has no arguments or keywords.

Defaults

Clustering is enabled on all switches.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

When you enter the no cluster run command on a cluster command switch or cluster command switch stack, the cluster command switch is disabled. Clustering is disabled, and the switch cannot become a candidate switch.

When you enter the no cluster run command on a cluster member switch, it is removed from the cluster. Clustering is disabled, and the switch cannot become a candidate switch.

When you enter the no cluster run command on a switch that is not part of a cluster, clustering is disabled on this switch. This switch cannot then become a candidate switch.

Examples

This example shows how to disable clustering on the cluster command switch:

Switch(config)# no cluster run

You can verify your setting by entering the show cluster privileged EXEC command.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


cluster standby-group

Use the cluster standby-group global configuration command to enable cluster command-switch redundancy by binding the cluster to an existing Hot Standby Router Protocol (HSRP). Entering the routing-redundancy keyword enables the same HSRP group to be used for cluster command-switch redundancy and routing redundancy. Use the no form of this command to return to the default setting.

cluster standby-group HSRP-group-name [routing-redundancy]

no cluster standby-group

Syntax Description

HSRP-group-name

Name of the HSRP group that is bound to the cluster. The group name is limited to 32 characters.

routing-redundancy

(Optional) Enable the same HSRP standby group to be used for cluster command-switch redundancy and routing redundancy.


Defaults

The cluster is not bound to any HSRP group.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Enter this command only on the cluster command switch. If you enter it on a cluster member switch, an error message appears.

The cluster command switch propagates the cluster-HSRP binding information to all cluster-HSRP capable members. Each cluster member switch stores the binding information in its NVRAM. The HSRP group name must be a valid standby group; otherwise, the command exits with an error.

The same group name should be used on all members of the HSRP standby group that is to be bound to the cluster. The same HSRP group name should also be used on all cluster-HSRP capable members for the HSRP group that is to be bound. (When not binding a cluster to an HSRP group, you can use different names on the cluster commander and the members.)

Examples

This example shows how to bind the HSRP group named my_hsrp to the cluster. This command is executed on the cluster command switch.

Switch(config)# cluster standby-group my_hsrp 

This example shows how to use the same HSRP group named my_hsrp for routing redundancy and cluster redundancy.

Switch(config)# cluster standby-group my_hsrp routing-redundancy

This example shows the error message when this command is executed on a cluster command switch and the specified HSRP standby group does not exist:

Switch(config)# cluster standby-group my_hsrp 
%ERROR: Standby (my_hsrp) group does not exist

This example shows the error message when this command is executed on a cluster member switch:

Switch(config)# cluster standby-group my_hsrp routing-redundancy
%ERROR: This command runs on a cluster command switch

You can verify your settings by entering the show cluster privileged EXEC command. The output shows whether redundancy is enabled in the cluster.

Related Commands

Command
Description

standby ip

Enables HSRP on the interface. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.

show standby

Displays standby group information. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.


cluster timer

Use the cluster timer global configuration command on the switch stack or on the a cluster command switch to set the interval in seconds between heartbeat messages. Use the no form of this command to set the interval to the default value.

cluster timer interval-in-secs

no cluster timer

Syntax Description

interval-in-secs

Interval in seconds between heartbeat messages. The range is 1 to 300 seconds.


Defaults

The interval is 8 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Enter this command with the cluster holdtime global configuration command only on the cluster command switch. The cluster command switch propagates the values to all its cluster members so that the setting is consistent among all switches in the cluster.

The holdtime is typically set as a multiple of the heartbeat interval timer (cluster timer). For example, it takes (holdtime-in-secs divided by the interval-in-secs) number of heartbeat messages to be missed in a row to declare a switch down.

Examples

This example shows how to change the heartbeat interval timer and the duration on the cluster command switch:

Switch(config)# cluster timer 3
Switch(config)# cluster holdtime 30

You can verify your settings by entering the show cluster privileged EXEC command.

Related Commands

Command
Description

show cluster

Displays the cluster status and a summary of the cluster to which the switch belongs.


define interface-range

Use the define interface-range global configuration command on the switch stack or on a standalone switch to create an interface-range macro. Use the no form of this command to delete the defined macro.

define interface-range macro-name interface-range

no define interface-range macro-name interface-range

Syntax Description

macro-name

Name of the interface-range macro; up to 32 characters.

interface-range

Interface range; for valid values for interface ranges, see "Usage Guidelines."


Defaults

This command has no default setting.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

The macro name is a 32-character maximum character string.

A macro can contain up to five ranges.

All interfaces in a range must be the same type; that is, all Fast Ethernet ports, all Gigabit Ethernet ports, all EtherChannel ports, or all VLANs, but you can combine multiple interface types in a macro.

When entering the interface-range, use this format:

type {first-interface} - {last-interface}

You must add a space between the first interface number and the hyphen when entering an interface-range. For example, gigabitethernet 1/0/1 - 2 is a valid range; gigabitethernet 1/0/1-2 is not a valid range

Valid values for type and interface:

vlan vlan-id, where vlan-id is from 1 to 4094

VLAN interfaces must have been configured with the interface vlan command (the show running-config privileged EXEC command displays the configured VLAN interfaces). VLAN interfaces not displayed by the show running-config command cannot be used in interface-ranges.

port-channel port-channel-number, where port-channel-number is from 1 to 48

fastethernet stack member/module/{first port} - {last port}

gigabitethernet stack member/module/{first port} - {last port}

For physical interfaces:

stack member is the number used to identify the switch within the stack. The number ranges from 1 to 9 and is assigned to the switch the first time the stack member initializes.

module is always 0.

the range is type stack member/0/number - number (for example, gigabitethernet 1/0/1 - 2).

When you define a range, you must enter a space before the hyphen (-), for example:

gigabitethernet1/0/1 - 2

You can also enter multiple ranges. When you define multiple ranges, you must enter a space after the first entry before the comma (,). The space after the comma is optional, for example:

fastethernet1/0/3, gigabitethernet1/0/1 - 2

fastethernet1/0/3 -4, gigabitethernet1/0/1 - 2

Examples

This example shows how to create a multiple-interface macro:

Switch(config)# define interface-range macro1 fastethernet1/0/1 - 2, gigabitethernet1/0/1 
- 2

Related Commands

Command
Description

interface range

Executes a command on multiple ports at the same time.

show running-config

Displays the current operating configuration, including defined macros. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


delete

Use the delete privileged EXEC command on the switch stack or on a standalone switch to delete a file or directory on the flash memory device.

delete [/force] [/recursive] filesystem:/file-url

Syntax Description

/force

(Optional) Suppress the prompt that confirms the deletion.

/recursive

(Optional) Delete the named directory and all subdirectories and the files contained in it.

filesystem:

Alias for a flash file system.

The syntax for the local flash file system on the stack member or the stack master:
flash:

From the stack master, the syntax for the local flash file system on a stack member:
flash member number:

/file-url

The path (directory) and filename to delete.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

If you use the /force keyword, you are prompted once at the beginning of the deletion process to confirm the deletion.

If you use the /recursive keyword without the /force keyword, you are prompted to confirm the deletion of every file.

The prompting behavior depends on the setting of the file prompt global configuration command. By default, the switch prompts for confirmation on destructive file operations. For more information about this command, see the Cisco IOS Command Reference for Release 12.1.

Examples

This example shows how to remove the directory that contains the old software image after a successful download of a new image:

Switch# delete /force /recursive flash:/old-image

You can verify that the directory was removed by entering the dir filesystem: privileged EXEC command.

Related Commands

Command
Description

archive download-sw

Downloads a new image to the switch and overwrites or keeps the existing image.


deny (ARP access-list configuration)

Use the deny Address Resolution Protocol (ARP) access-list configuration command on the switch stack or on a standalone switch to deny an ARP packet based on matches against the DHCP bindings. Use the no form of this command to remove the specified access control entry (ACE) from the access list.

deny {[request] ip {any | host sender-ip | sender-ip sender-ip-mask} mac {any | host sender-mac | sender-mac sender-mac-mask} | response ip {any | host sender-ip | sender-ip sender-ip-mask} [{any | host target-ip | target-ip target-ip-mask}] mac {any | host sender-mac | sender-mac sender-mac-mask} [{any | host target-mac | target-mac target-mac-mask}]} [log]

no deny {[request] ip {any | host sender-ip | sender-ip sender-ip-mask} mac {any | host sender-mac | sender-mac sender-mac-mask} | response ip {any | host sender-ip | sender-ip sender-ip-mask} [{any | host target-ip | target-ip target-ip-mask}] mac {any | host sender-mac | sender-mac sender-mac-mask} [{any | host target-mac | target-mac target-mac-mask}]} [log]

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

request

(Optional) Define a match for the ARP request. When request is not specified, matching is performed against all ARP packets.

ip

Specify the sender IP address.

any

Deny any IP or MAC address.

host sender-ip

Deny the specified sender IP address.

sender-ip sender-ip-mask

Deny the specified range of sender IP addresses.

mac

Deny the sender MAC address.

host sender-mac

Deny a specific sender MAC address.

sender-mac sender-mac-mask

Deny the specified range of sender MAC addresses.

response ip

Define the IP address values for the ARP responses.

host target-ip

Deny the specified target IP address.

target-ip target-ip-mask

Deny the specified range of target IP addresses.

mac

Deny the MAC address values for the ARP responses.

host target-mac

Deny the specified target MAC address.

target-mac target-mac-mask

Deny the specified range of target MAC addresses.

log

(Optional) Log a packet when it matches the ACE.


Defaults

There are no default settings. However, at the end of the ARP access list, there is an implicit deny ip any mac any command.

Command Modes

ARP access-list configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

You can add deny clauses to drop ARP packets based on matching criteria.

Examples

This example shows how to define an ARP access list and to deny both ARP requests and ARP responses from a host with an IP address of 1.1.1.1 and a MAC address of 0000.0000.abcd:

Switch(config)# arp access-list static-hosts
Switch(config-arp-nacl)# deny ip host 1.1.1.1 mac host 0000.0000.abcd
Switch(config-arp-nacl)# end

You can verify your settings by entering the show arp access-list privileged EXEC command.

Related Commands

Command
Description

arp access-list

Defines an ARP access control list (ACL).

ip arp inspection filter vlan

Permits ARP requests and responses from a host configured with a static IP address.

permit (ARP access-list configuration)

Permits an ARP packet based on matches against the DHCP bindings.

show arp access-list

Displays detailed information about ARP access lists.


deny (MAC access-list configuration)

Use the deny MAC access-list configuration command on the switch stack or on a standalone switch to prevent non-IP traffic from being forwarded if the conditions are matched. Use the no form of this command to remove a deny condition from the named MAC access list.

{deny | permit} {any | host src-MAC-addr | src-MAC-addr mask} {any | host dst-MAC-addr | dst-MAC-addr mask} [type mask | aarp | amber | cos cos | dec-spanning | decnet-iv | diagnostic | dsm | etype-6000 | etype-8042 | lat | lavc-sca | lsap lsap mask |mop-console | mop-dump | msdos | mumps | netbios | vines-echo | vines-ip | xns-idp]

no {deny | permit} {any | host src-MAC-addr | src-MAC-addr mask} {any | host dst-MAC-addr | dst-MAC-addr mask} [type mask | aarp | amber | cos cos | dec-spanning | decnet-iv | diagnostic | dsm | etype-6000 | etype-8042 | lat | lavc-sca | lsap lsap mask | mop-console | mop-dump | msdos | mumps | netbios | vines-echo | vines-ip | xns-idp]

Syntax Description

any

Keyword to specify to deny any source or destination MAC address.

host src MAC-addr |
src-MAC-addr mask

Define a host MAC address and optional subnet mask. If the source address for a packet matches the defined address, non-IP traffic from that address is denied.

host dst-MAC-addr |
dst-MAC-addr mask

Define a destination MAC address and optional subnet mask. If the destination address for a packet matches the defined address, non-IP traffic to that address is denied.

type mask

(Optional) Use the Ethertype number of a packet with Ethernet II or SNAP encapsulation to identify the protocol of the packet.

The type is 0 to 65535, specified in hexadecimal.

The mask is a mask of don't care bits applied to the Ethertype before testing for a match.

aarp

(Optional) Select Ethertype AppleTalk Address Resolution Protocol that maps a data-link address to a network address.

amber

(Optional) Select EtherType DEC-Amber.

cos cos

(Optional) Select a class of service (CoS) number from 0 to 7 to set priority. Filtering on CoS can be performed only in hardware. A warning message reminds the user if the cos option is configured.

dec-spanning

(Optional) Select EtherType Digital Equipment Corporation (DEC) spanning tree.

decnet-iv

(Optional) Select EtherType DECnet Phase IV protocol.

diagnostic

(Optional) Select EtherType DEC-Diagnostic.

dsm

(Optional) Select EtherType DEC-DSM.

etype-6000

(Optional) Select EtherType 0x6000.

etype-8042

(Optional) Select EtherType 0x8042.

lat

(Optional) Select EtherType DEC-LAT.

lavc-sca

(Optional) Select EtherType DEC-LAVC-SCA.

lsap lsap-number mask

(Optional) Use the LSAP number (0 to 65535) of a packet with 802.2 encapsulation to identify the protocol of the packet.

mask is a mask of don't care bits applied to the LSAP number before testing for a match.

mop-console

(Optional) Select EtherType DEC-MOP Remote Console.

mop-dump

(Optional) Select EtherType DEC-MOP Dump.

msdos

(Optional) Select EtherType DEC-MSDOS.

mumps

(Optional) Select EtherType DEC-MUMPS.

netbios

(Optional) Select EtherType DEC- Network Basic Input/Output System (NETBIOS).

vines-echo

(Optional) Select EtherType Virtual Integrated Network Service (VINES) Echo from Banyan Systems.

vines-ip

(Optional) Select EtherType VINES IP.

xns-idp

(Optional) Select EtherType Xerox Network Systems (XNS) protocol suite (0 to 65535), an arbitrary Ethertype in decimal, hexadecimal, or octal.



Note Though visible in the command-line help strings, appletalk is not supported as a matching condition.


To filter IPX traffic, you use the type mask or lsap lsap mask keywords, depending on the type of IPX encapsulation being used. Filter criteria for IPX encapsulation types as specified in Novell terminology and Cisco IOS terminology are listed in Table 2-4.

Table 2-4 IPX Filtering Criteria

IPX Encapsulation Type
Filter Criterion
Cisco IOS Name
Novel Name

arpa

Ethernet II

Ethertype 0x8137

snap

Ethernet-snap

Ethertype 0x8137

sap

Ethernet 802.2

LSAP 0xE0E0

novell-ether

Ethernet 802.3

LSAP 0xFFFF


Defaults

This command has no defaults. However; the default action for a MAC-named ACL is to deny.

Command Modes

MAC-access list configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You enter MAC-access list configuration mode by using the mac access-list extended global configuration command.

If you use the host keyword, you cannot enter an address mask; if you do not use the host keyword, you must enter an address mask.

When an access control entry (ACE) is added to an access control list, an implied deny-any-any condition exists at the end of the list. That is, if there are no matches, the packets are denied. However, before the first ACE is added, the list permits all packets.


Note For more information about named MAC extended access lists, see the software configuration guide for this release.


Examples

This example shows how to define the named MAC extended access list to deny NETBIOS traffic from any source to MAC address 00c0.00a0.03fa. Traffic matching this list is denied.

Switch(config-ext-macl)# deny any host 00c0.00a0.03fa netbios.

This example shows how to remove the deny condition from the named MAC extended access list:

Switch(config-ext-macl)# no deny any 00c0.00a0.03fa 0000.0000.0000 netbios.

This example denies all packets with Ethertype 0x4321:

Switch(config-ext-macl)# deny any any 0x4321 0

You can verify your settings by entering the show access-lists privileged EXEC command.

Related Commands

Command
Description

mac access-list extended

Creates an access list based on MAC addresses for non-IP traffic.

permit (MAC access-list configuration)

Permits non-IP traffic to be forwarded if conditions are matched.

show access-lists

Displays access control lists configured on a switch.


dot1x

Use the dot1x global configuration command on the switch stack or on a standalone switch to globally enable 802.1x. Use the no form of this command to return to the default setting.

dot1x {system-auth-control} | {guest-vlan supplicant}

no dot1x {system-auth-control} | {guest-vlan supplicant}

Syntax Description

system-auth-control

Enable 802.1x globally on the switch.

guest-vlan supplicant

Enable optional guest VLAN behavior globally on the switch.


Defaults

802.1x is disabled, and the optional guest VLAN behavior is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced.

12.2(25)SE

The guest-vlan supplicant keywords were added.


Usage Guidelines

You must enable authentication, authorization, and accounting (AAA) and specify the authentication method list before globally enabling 802.1x. A method list describes the sequence and authentication methods to be queried to authenticate a user.

Before globally enabling 802.1x on a switch, remove the EtherChannel configuration from the interfaces on which 802.1x and EtherChannel are configured.

If you are using a device running the Cisco Access Control Server (ACS) application for 802.1x authentication with EAP-Transparent LAN Services (TLS) and with EAP-MD5 and your switch is running Cisco IOS Release 12.1(14)EA1, make sure that the device is running ACS Version 3.2.1 or later.

You can use the guest-vlan supplicant keywords to enable the optional 802.1x guest VLAN behavior globally on the switch. For more information, see the dot1x guest-vlan command.

Examples

This example shows how to globally enable 802.1x on a switch:

Switch(config)# dot1x system-auth-control

This example shows how to globally enable the optional guest VLAN behavior on a switch:

Switch(config)# dot1x guest-vlan supplicant

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

dot1x guest-vlan

Enables and specifies an active VLAN as an 802.1x guest VLAN.

dot1x port-control

Enables manual control of the authorization state of the port.

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x default

Use the dot1x default interface configuration command on the switch stack or on a standalone switch to reset the configurable 802.1x parameters to their default values.

dot1x default

Syntax Description

This command has no arguments or keywords.

Defaults

These are the default values:

The per-port 802.1x protocol enable state is disabled (force-authorized).

The number of seconds between re-authentication attempts is 3600 seconds.

The periodic re-authentication is disabled.

The quiet period is 60 seconds.

The retransmission time is 30 seconds.

The maximum retransmission number is 2 times.

The host mode is single host.

The client timeout period is 30 seconds.

The authentication server timeout period is 30 seconds.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

This command was changed to the interface configuration mode.


Examples

This example shows how to reset the configurable 802.1x parameters on a port:

Switch(config-if)# dot1x default

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x guest-vlan

Use the dot1x guest-vlan interface configuration command on the switch stack or on a standalone switch to specify an active VLAN as an 802.1x guest VLAN. Use the no form of this command to return to the default setting.

dot1x guest-vlan vlan-id

no dot1x guest-vlan

Syntax Description

vlan-id

Specify an active VLAN as an 802.1x guest VLAN. The range is 1 to 4094.


Defaults

No guest VLAN is configured.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced.

12.2(25)SE

This command was modified to change the default guest VLAN behavior.


Usage Guidelines

For each 802.1x port on the switch, you can configure a guest VLAN to provide limited services to clients (a device or workstation connected to the switch), such as downloading the 802.1x client software. These users might be upgrading their systems for 802.1x authentication, and some hosts, such as Windows 98 systems, might not be 802.1x-capable.

When you enable a guest VLAN on an 802.1x port, the switch assigns clients to a guest VLAN when the authentication server does not receive a response to its Extensible Authentication Protocol over LAN (EAPOL) request/identity frame or when EAPOL packets are not sent by the client.

Before Cisco IOS Release 12.2(25)SE, the switch did not maintain the EAPOL packet history and allowed clients that failed authentication access to the guest VLAN, regardless of whether EAPOL packets had been detected on the interface. You can use the dot1x guest-vlan supplicant global configuration command to enable this optional behavior.

With Cisco IOS Release 12.2(25)SE and later, the switch maintains the EAPOL packet history. If another EAPOL packet is detected on the interface during the lifetime of the link, network access is denied. The EAPOL history is reset upon loss of link.

Any number of non-802.1x-capable clients are allowed access when the switch port is moved to the guest VLAN. If an 802.1x-capable client joins the same port on which the guest VLAN is configured, the port is put into the unauthorized state in the user-configured access VLAN, and authentication is restarted.

Guest VLANs are supported on 802.1x ports in single-host or multiple-hosts mode.

You can configure any active VLAN except an RSPAN VLAN, private VLAN, or a voice VLAN as an 802.1x guest VLAN. The guest VLAN feature is not supported on internal VLANs (routed ports) or trunk ports; it is supported only on access ports.

After you configure a guest VLAN for an 802.1x port to which a DHCP client is connected, you might need to get a host IP address from a DHCP server. You can also change the settings for restarting the 802.1x authentication process on the switch before the DHCP process on the client times out and tries to get a host IP address from the DHCP server. Decrease the settings for the 802.1x authentication process (802.1x quiet period and switch-to-client transmission time).

Examples

This example shows how to specify VLAN 5 as an 802.1x guest VLAN:

Switch(config-if)# dot1x guest-vlan 5

This example shows how to set 3 as the quiet time on the switch, to set 15 as the number of seconds that the switch waits for a response to an EAP-request/identity frame from the client before resending the request, and to enable VLAN 2 as an 802.1x guest VLAN when an 802.1X port is connected to a DHCP client:

Switch(config-if)# dot1x timeout quiet-period 3
Switch(config-if)# dot1x timeout tx-period 15
Switch(config-if)# dot1x guest-vlan 2

This example shows how to enable the optional guest VLAN behavior and to specify VLAN 5 as an 802.1x guest VLAN:

Switch(config)# dot1x guest-vlan supplicant
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# dot1x guest-vlan 5

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

dot1x

Enables the optional guest VLAN supplicant feature.

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x host-mode

Use the dot1x host-mode interface configuration command on the switch stack or on a standalone switch to allow a single host (client) or multiple hosts on an 802.1x-authorized port that has the dot1x port-control interface configuration command set to auto. Use the no form of this command to return to the default setting.

dot1x host-mode {multi-host | single-host}

no dot1x host-mode [multi-host | single-host]

Syntax Description

multi-host

Enable multiple-hosts mode on the switch.

single-host

Enable single-host mode on the switch.


Defaults

The default is single-host mode.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced. It replaces the dot1x multiple-hosts interface configuration command.


Usage Guidelines

Use this command to limit an 802.1x-enabled port to a single client or to attach multiple clients to an 802.1x-enabled port. In multiple-hosts mode, only one of the attached hosts must be successfully authorized for all hosts to be granted network access. If the port becomes unauthorized (re-authentication fails or an Extensible Authentication Protocol over LAN [EAPOL]-logoff message is received), all attached clients are denied access to the network.

Before entering this command, make sure that the dot1x port-control interface configuration command is set to auto for the specified port.

Examples

This example shows how to enable 802.1x globally, to enable 802.1x on a port, and to enable multiple-hosts mode:

Switch(config)# dot1x system-auth-control
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# dot1x port-control auto
Switch(config-if)# dot1x host-mode multi-host

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x initialize

Use the dot1x initialize privileged EXEC command on the switch stack or on a standalone switch to manually return the specified 802.1x-enabled port to an unauthorized state before initiating a new authentication session on the port.

dot1x initialize interface interface-id

Syntax Description

interface interface-id

Port to be initialized.


Defaults

There is no default setting.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(14)EA1

This command was introduced.


Usage Guidelines

Use this command to initialize the 802.1x state machines and to set up a fresh environment for authentication. After you enter this command, the port status becomes unauthorized.

There is no no form of this command.

Examples

This example shows how to manually initialize a port:

Switch# dot1x initialize interface gigabitethernet2/0/2

You can verify the unauthorized port status by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x max-reauth-req

Use the dot1x max-reauth-req interface configuration command on the switch stack or on a standalone switch to set the maximum number of times that the switch restarts the authentication process before a port transitions to the unauthorized state. Use the no form of this command to return to the default setting.

dot1x max-reauth-req count

no dot1x max-reauth-req

Syntax Description

count

Number of times that the switch restarts the authentication process before the port transitions to the unauthorized state. The range is 1 to 10.


Defaults

The default is 2 times.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(18)SE

This command was introduced.


Usage Guidelines

You should change the default value of this command only to adjust for unusual circumstances such as unreliable links or specific behavioral problems with certain clients and authentication servers.

Examples

This example shows how to set 4 as the number of times that the switch restarts the authentication process before the port transitions to the unauthorized state:

Switch(config-if)# dot1x max-reauth-req 4

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

dot1x max-req

Sets the maximum number of times that the switch forwards an EAP-request/identity frame (assuming that no response is received) to the authentication server before restarting the authentication process.

dot1x timeout tx-period

Sets the number of seconds that the switch waits for a response to an EAP-request/identity frame from the client before resending the request.

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x max-req

Use the dot1x max-req interface configuration command on the switch stack or on a standalone switch to set the maximum number of times that the switch sends an Extensible Authentication Protocol (EAP)-request/identity frame (assuming that no response is received) to the client before restarting the authentication process. Use the no form of this command to return to the default setting.

dot1x max-req count

no dot1x max-req

Syntax Description

count

Number of times that the switch sends an EAP-request/identity frame before restarting the authentication process. The range is 1 to 10.


Defaults

The default is 2 times.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

This command was changed to the interface configuration mode.


Usage Guidelines

You should change the default value of this command only to adjust for unusual circumstances such as unreliable links or specific behavioral problems with certain clients and authentication servers.

Examples

This example shows how to set 5 as the number of times that the switch sends an EAP-request/identity frame before restarting the authentication process:

Switch(config-if)# dot1x max-req 5

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

dot1x timeout tx-period

Sets the number of seconds that the switch waits for a response to an EAP-request/identity frame from the client before resending the request.

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x multiple-hosts

This is an obsolete command.

In past releases, the dot1x multiple-hosts interface configuration command was used on the switch stack or on a standalone switch to allow multiple hosts (clients) on an 802.1x-authorized port.

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

The dot1x multiple-hosts interface configuration command was replaced by the dot1x host-mode interface configuration command.


Related Commands

Command
Description

dot1x host-mode

Sets the 802.1x host mode on a port.

show dot1x

Displays 802.1x statistics, administrative status, and operational status for the switch or for the specified port.


dot1x port-control

Use the dot1x port-control interface configuration command on the switch stack or on a standalone switch to enable manual control of the authorization state of the port. Use the no form of this command to return to the default setting.

dot1x port-control {auto | force-authorized | force-unauthorized}

no dot1x port-control

Syntax Description

auto

Enable 802.1x authentication on the port and cause the port to change to the authorized or unauthorized state based on the 802.1x authentication exchange between the switch and the client.

force-authorized

Disable 802.1x authentication on the port and cause the port to transition to the authorized state without an authentication exchange. The port sends and receives normal traffic without 802.1x-based authentication of the client.

force-unauthorized

Deny all access through this port by forcing the port to change to the unauthorized state, ignoring all attempts by the client to authenticate. The switch cannot provide authentication services to the client through the port.


Defaults

The default is force-authorized.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You must globally enable 802.1x on the switch by using the dot1x system-auth-control global configuration command before enabling 802.1x on a specific port.

The 802.1x protocol is supported on Layer 2 static-access ports, voice VLAN ports, and Layer 3 routed ports.

You can use the auto keyword only if the port is not configured as one of these:

Trunk port—If you try to enable 802.1x on a trunk port, an error message appears, and 802.1x is not enabled. If you try to change the mode of an 802.1x-enabled port to trunk, an error message appears, and the port mode is not changed.

Dynamic ports—A port in dynamic mode can negotiate with its neighbor to become a trunk port. If you try to enable 802.1x on a dynamic port, an error message appears, and 802.1x is not enabled. If you try to change the mode of an 802.1x-enabled port to dynamic, an error message appears, and the port mode is not changed.

Dynamic-access ports—If you try to enable 802.1x on a dynamic-access (VLAN Query Protocol [VQP]) port, an error message appears, and 802.1x is not enabled. If you try to change an 802.1x-enabled port to dynamic VLAN assignment, an error message appears, and the VLAN configuration is not changed.

EtherChannel port—Do not configure a port that is an active or a not-yet-active member of an EtherChannel as an 802.1x port. If you try to enable 802.1x on an EtherChannel port, an error message appears, and 802.1x is not enabled.


Note In software releases earlier than Cisco IOS Release 12.2(18)SE, if 802.1x is enabled on a not-yet active port of an EtherChannel, the port does not join the EtherChannel.


Switched Port Analyzer (SPAN) and Remote SPAN (RSPAN) destination ports—You can enable 802.1x on a port that is a SPAN or RSPAN destination port. However, 802.1x is disabled until the port is removed as a SPAN or RSPAN destination. You can enable 802.1x on a SPAN or RSPAN source port.

To globally disable 802.1x on the switch, use the no dot1x system-auth-control global configuration command. To disable 802.1x on a specific port, use the no dot1x port-control interface configuration command.

Examples

This example shows how to enable 802.1x on a port:

Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# dot1x port-control auto

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x re-authenticate

Use the dot1x re-authenticate privileged EXEC command on the switch stack or on a standalone switch to manually initiate a re-authentication of all 802.1x-enabled ports or the specified 802.1x-enabled port.

dot1x re-authenticate interface interface-id

Syntax Description

interface interface-id

Stack switch number, module, and port number of the interface to re-authenticate.


Defaults

There is no default setting.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You can use this command to re-authenticate a client without waiting for the configured number of seconds between re-authentication attempts (re-authperiod) and automatic re-authentication.

Examples

This example shows how to manually re-authenticate the device connected to a port:

Switch# dot1x re-authenticate interface gigabitethernet2/0/1

dot1x re-authentication

This is an obsolete command.

In past releases, the dot1x re-authentication global configuration command was used on the switch stack or on a standalone switch to set the amount of time between periodic re-authentication attempts.

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

The dot1x reauthentication interface configuration command replaced the dot1x re-authentication global configuration command.


Related Commands

Command
Description

dot1x reauthentication

Sets the number of seconds between re-authentication attempts.

show dot1x

Displays 802.1x statistics, administrative status, and operational status for the switch or for the specified port.


dot1x reauthentication

Use the dot1x reauthentication interface configuration command on the switch stack or on a standalone switch to enable periodic re-authentication of the client. Use the no form of this command to return to the default setting.

dot1x reauthentication

no dot1x reauthentication

Syntax Description

This command has no arguments or keywords.

Defaults

Periodic re-authentication is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced. It replaces the dot1x re-authentication global configuration command (with the hyphen).


Usage Guidelines

You configure the amount of time between periodic re-authentication attempts by using the dot1x timeout reauth-period interface configuration command.

Examples

This example shows how to disable periodic re-authentication of the client:

Switch(config-if)# no dot1x reauthentication

This example shows how to enable periodic re-authentication and to set the number of seconds between re-authentication attempts to 4000 seconds:

Switch(config-if)# dot1x reauthentication
Switch(config-if)# dot1x timeout reauth-period 4000

You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.

Related Commands

Command
Description

dot1x timeout reauth-period

Sets the number of seconds between re-authentication attempts.

show dot1x [interface interface-id]

Displays 802.1x status for the specified port.


dot1x timeout

Use the dot1x timeout interface configuration command on the switch stack or on a standalone switch to set 802.1x timers. Use the no form of this command to return to the default setting.

dot1x timeout {quiet-period seconds | reauth-period seconds | server-timeout seconds | supp-timeout seconds | tx-period seconds}

no dot1x timeout {quiet-period | reauth-period | server-timeout | supp-timeout | tx-period}

Syntax Description

quiet-period seconds

Number of seconds that the switch remains in the quiet state following a failed authentication exchange with the client. The range is 1 to 65535.

reauth-period seconds

Number of seconds between re-authentication attempts. The range is 1 to 65535.

server-timeout seconds

Number of seconds that the switch waits for the retransmission of packets by the switch to the authentication server. The range is 30 to 65535.

supp-timeout seconds

Number of seconds that the switch waits for the retransmission of packets by the switch to the 802.1x client. The range is 30 to 65535.

tx-period seconds

Number of seconds that the switch waits for a response to an EAP-request/identity frame from the client before retransmitting the request. The range is 15 to 65535.


Defaults

These are the default settings:

reauth-period is 3600 seconds.

quiet-period is 60 seconds.

tx-period is 30 seconds.

supp-timeout is 30 seconds.

server-timeout is 30 seconds.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

The supp-timeout and server-timeout keywords were added, and the command was changed to the interface configuration mode.

12.2(18)SE

The ranges for the server-timeout, supp-timeout, and tx-period keywords were changed.


Usage Guidelines

You should change the default value of this command only to adjust for unusual circumstances such as unreliable links or specific behavioral problems with certain clients and authentication servers.

The dot1x timeout reauth-period interface configuration command affects the behavior of the switch only if you have enabled periodic re-authentication by using the dot1x reauthentication interface configuration command.

During the quiet period, the switch does not accept or initiate any authentication requests. If you want to provide a faster response time to the user, enter a smaller number than the default.

Examples

This example shows how to enable periodic re-authentication and to set 4000 as the number of seconds between re-authentication attempts:

Switch(config-if)# dot1x reauthentication
Switch(config-if)# dot1x timeout reauth-period 4000

This example shows how to set 30 seconds as the quiet time on the switch:

Switch(config-if)# dot1x timeout quiet-period 30

This example shows how to set 45 seconds as the switch-to-authentication server retransmission time:

Switch(config)# dot1x timeout server-timeout 45

This example shows how to set 45 seconds as the switch-to-client retransmission time for the EAP request frame:

Switch(config-if)# dot1x timeout supp-timeout 45

This example shows how to set 60 as the number of seconds to wait for a response to an EAP-request/identity frame from the client before re-transmitting the request:

Switch(config-if)# dot1x timeout tx-period 60

You can verify your settings by entering the show dot1x privileged EXEC command.

Related Commands

Command
Description

dot1x max-req

Sets the maximum number of times that the switch sends an EAP-request/identity frame before restarting the authentication process.

dot1x reauthentication

Enables periodic re-authentication of the client.

show dot1x

Displays 802.1x status for all ports.


duplex

Use the duplex interface configuration command on the switch stack or on a standalone switch to specify the duplex mode of operation for a port. Use the no form of this command to return the port to its default value.

duplex {auto | full | half}

no duplex

Syntax Description

auto

Enable automatic duplex configuration; port automatically detects whether it should run in full- or half-duplex mode, depending on the attached device mode.

full

Enable full-duplex mode.

half

Enable half-duplex mode (only for interfaces operating at 10 Mbps or 100 Mbps). You cannot configure half-duplex mode for interfaces operating at 1000 Mbps or 10,000 Mbps.


Defaults

The default is auto for Fast Ethernet and Gigabit Ethernet ports and for 1000BASE-T small form-factor pluggable (SFP) modules.

The default is half for 100BASE-FX MMF SFP modules.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

This command is not available on SFP module ports unless a 1000BASE-T SFP module or a 100BASE-FX MMF SFP module is in the port. All other SFP modules operate only in full-duplex mode.

When a 1000BASE-T SFP module is in the SFP module port, you can configure duplex mode to auto or full.

When a 100BASE-FX SFP module is in the SFP module port, you can configure duplex mode to half or full. Although the auto keyword is available, it puts the interface in half-duplex mode (the default) because the 100BASE-FX SFP module does not support autonegotiation.

This command is not available on a 10-Gigabit Ethernet interface.

Certain ports can be configured to be either full duplex or half duplex. Applicability of this command depends on the device to which the switch is attached.

For Fast Ethernet ports, setting the port to auto has the same effect as specifying half if the attached device does not autonegotiate the duplex parameter.

For Gigabit Ethernet ports, setting the port to auto has the same effect as specifying full if the attached device does not autonegotiate the duplex parameter.


Note Half-duplex mode is supported on Gigabit Ethernet interfaces if duplex mode is auto and the connected device is operating at half duplex. However, you cannot configure these interfaces to operate in half-duplex mode.


If both ends of the line support autonegotiation, we highly recommend using the default autonegotiation settings. If one interface supports autonegotiation and the other end does not, configure duplex and speed on both interfaces; do use the auto setting on the supported side.

If the speed is set to auto, the switch negotiates with the device at the other end of the link for the speed setting and then forces the speed setting to the negotiated value. The duplex setting remains as configured on each end of the link, which could result in a duplex setting mismatch.

Beginning with Cisco IOS Release 12.2(20)SE1, you can configure the duplex setting when the speed is set to auto.


Caution Changing the interface speed and duplex mode configuration might shut down and re-enable the interface during the reconfiguration.


Note For guidelines on setting the switch speed and duplex parameters, see the software configuration guide for this release.


Examples

This example shows how to configure an interface for full duplex operation:

Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# duplex full

You can verify your setting by entering the show interfaces privileged EXEC command.

Related Commands

Command
Description

show interfaces

Displays the interface settings on the switch.

speed

Sets the speed on a 10/100 or 10/100/1000 Mbps interface.


errdisable detect cause

Use the errdisable detect cause global configuration command on the switch stack or on a standalone switch to enable error-disabled detection for a specific cause or all causes. Use the no form of this command to disable the error-disabled detection feature.

errdisable detect cause {all | arp-inspection | dhcp-rate-limit | dtp-flap | gbic-invalid | l2ptguard | link-flap | loopback | pagp-flap}

no errdisable detect cause {all | arp-inspection | dhcp-rate-limit | dtp-flap | gbic-invalid | l2ptguard | link-flap | pagp-flap}

Syntax Description

all

Enable error detection for all error-disable causes.

arp-inspection

Enable error detection for dynamic Address Resolution Protocol (ARP) inspection.

dhcp-rate-limit

Enable error detection for DHCP snooping.

dtp-flap

Enable error detection for the Dynamic Trunking Protocol (DTP) flapping.

gbic-invalid

Enable error detection for an invalid Gigabit Interface Converter (GBIC) module.

Note On the Catalyst 3750 switch, this error refers to an invalid small form-factor pluggable (SFP) module.

l2ptguard

Enable error detection for a Layer 2 protocol-tunnel error-disabled cause.

link-flap

Enable error detection for link-state flapping.

loopback

Enable error detection for detected loopbacks.

pagp-flap

Enable error detection for the Port Aggregation Protocol (PAgP) flap error-disabled cause.


Defaults

Detection is enabled for all causes.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(19)EA1

The dhcp-rate-limit keyword was added.

12.2(20)SE

The arp-inspection keyword was added.

12.2(25)SE

The l2ptguard keyword was added.


Usage Guidelines

A cause (all, dhcp-rate-limit, and so forth) is the reason why the error-disabled state occurred. When a cause is detected on an interface, the interface is placed in an error-disabled state, an operational state that is similar to a link-down state.

If you set a recovery mechanism for the cause by entering the errdisable recovery global configuration command for the cause, the interface is brought out of the error-disabled state and allowed to retry the operation when all causes have timed out. If you do not set a recovery mechanism, you must enter the shutdown and then the no shutdown commands to manually recover an interface from the error-disabled state.

Examples

This example shows how to enable error-disabled detection for the link-flap error-disabled cause:

Switch(config)# errdisable detect cause link-flap

You can verify your setting by entering the show errdisable detect privileged EXEC command.

Related Commands

Command
Description

show errdisable detect

Displays errdisable detection information.

show interfaces status err-disabled

Displays interface status or a list of interfaces in the error-disabled state.


errdisable recovery

Use the errdisable recovery global configuration command on the switch stack or on a standalone switch to configure the recover mechanism variables. Use the no form of this command to return to the default setting.

errdisable recovery {cause {all | arp-inspection | bpduguard | channel-misconfig | dhcp-rate-limit | dtp-flap | gbic-invalid | l2ptguard | link-flap | loopback | pagp-flap | psecure-violation | security-violation | udld | vmps} | {interval interval}

no errdisable recovery {cause {all | arp-inspection | bpduguard | channel-misconfig | dhcp-rate-limit | dtp-flap | gbic-invalid | l2ptguard | link-flap | loopback | pagp-flap | psecure-violation | security-violation | udld | vmps} | {interval interval}

Syntax Description

cause

Enable the error-disabled mechanism to recover from a specific cause.

all

Enable the timer to recover from all error-disabled causes.

bpduguard

Enable the timer to recover from the bridge protocol data unit (BPDU) guard error-disabled state.

arp-inspection

Enable the timer to recover from the Address Resolution Protocol (ARP) inspection error-disabled state.

channel-misconfig

Enable the timer to recover from the EtherChannel misconfiguration error-disabled state.

dhcp-rate-limit

Enable the timer to recover from the DHCP snooping error-disabled state.

dtp-flap

Enable the timer to recover from the Dynamic Trunking Protocol (DTP) flap error-disable state.

gbic-invalid

Enable the timer to recover from an invalid Gigabit Interface Converter (GBIC) module error-disable state.

Note On the Catalyst 3750 switch, this error refers to an invalid small form-factor pluggable (SFP) error-disable state.

l2ptguard

Enable the timer to recover from a Layer 2 protocol tunnel error-disabled state.

link-flap

Enable the timer to recover from the link-flap error-disabled state.

loopback

Enable the timer to recover from a loopback error-disabled state.

pagp-flap

Enable the timer to recover from the Port Aggregation Protocol (PAgP)-flap error-disabled state.

psecure-violation

Enable the timer to recover from a port security violation disable state.

security-violation

Enable the timer to recover from an 802.1x-violation disabled state

udld

Enable the timer to recover from the UniDirectional Link Detection (UDLD) error-disabled state.

vmps

Enable the timer to recover from the VLAN Membership Policy Server (VMPS) error-disabled state.

interval interval

Specify the time to recover from the specified error-disabled state. The range is 30 to 86400 seconds. The same interval is applied to all causes. The default interval is 300 seconds.

Note The error-disabled recovery timer is initialized at a random differential from the configured interval value. The difference between the actual timeout value and the configured value can be up to 15 percent of the configured interval.



Note Though visible in the command-line help strings, the ilpower, storm-control, and unicast-flood keywords are not supported.


Defaults

Recovery is disabled for all causes.

The default recovery interval is 300 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

The security-violation keyword was added. The gbic-invalid keyword is supported for SFP module ports.

12.1(19)EA1

The dhcp-rate-limit keyword was added.

12.2(18)SE

The channel-misconfig keyword was added.

12.2(20)SE

The arp-inspection keyword was added.

12.2(25)SE

The l2ptguard keyword was added.


Usage Guidelines

A cause (all, bpduguard and so forth) is defined as the reason that the error-disabled state occurred. When a cause is detected on an interface, the interface is placed in error-disabled state, an operational state similar to link-down state. If you do not enable errdisable recovery for the cause, the interface stays in error-disabled state until you enter a shutdown and no shutdown interface configuration command. If you enable the recovery for a cause, the interface is brought out of the error-disabled state and allowed to retry the operation again when all the causes have timed out.

Otherwise, you must enter the shutdown then no shutdown commands to manually recover an interface from the error-disabled state.

Examples

This example shows how to enable the recovery timer for the BPDU guard error-disabled cause:

Switch(config)# errdisable recovery cause bpduguard

This example shows how to set the timer to 500 seconds:

Switch(config)# errdisable recovery interval 500

You can verify your settings by entering the show errdisable recovery privileged EXEC command.

Related Commands

Command
Description

show errdisable recovery

Displays errdisable recovery timer information.

show interfaces status err-disabled

Displays interface status or a list of interfaces in error-disabled state.


flowcontrol

Use the flowcontrol interface configuration command on the switch stack or on a standalone switch to set the receive flow-control state for an interface. When flow control send is operable and on for a device and it detects any congestion at its end, it notifies the link partner or the remote device of the congestion by sending a pause frame. When flow control receive is on for a device and it receives a pause frame, it stops sending any data packets. This prevents any loss of data packets during the congestion period.

Use the receive off keywords to disable flow control.

flowcontrol receive {desired | off | on}


Note The Catalyst 3750 switch can only receive pause frames.


Syntax Description

receive

Set whether the interface can receive flow-control packets from a remote device.

desired

Allow an interface to operate with an attached device that is required to send flow-control packets or with an attached device that is not required to but can send flow-control packets.

off

Turn off the ability of an attached device to send flow-control packets to an interface.

on

Allow an interface to operate with an attached device that is required to send flow-control packets or with an attached device that is not required to but can send flow-control packets.


Defaults

The default is flowcontrol receive off.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

The switch does not support sending flow-control pause frames.

Note that the on and desired keywords have the same result.

When you use the flowcontrol command to set a port to control traffic rates during congestion, you are setting flow control on a port to one of these conditions:

receive on or desired: The port cannot send out pause frames, but can operate with an attached device that is required to or is able to send pause frames; the port is able to receive pause frames.

receive off: Flow control does not operate in either direction. In case of congestion, no indication is given to the link partner and no pause frames are sent or received by either device.

Table 2-5 shows the flow control results on local and remote ports for a combination of settings. The table assumes that receive desired has the same results as using the receive on keywords.

Table 2-5 Flow Control Settings and Local and Remote Port Flow Control Resolution 

Flow Control Settings
Flow Control Resolution
Local Device
Remote Device
Local Device
Remote Device

send off/receive on

send on/receive on

send on/receive off

send desired/receive on

send desired/receive off

send off/receive on

send off/receive off

Receives only

Receives only

Receives only

Receives only

Receives only

Does not send or receive

Sends and receives

Sends only

Sends and receives

Sends only

Receives only

Does not send or receive

send off/receive off

send on/receive on

send on/receive off

send desired/receive on

send desired/receive off

send off/receive on

send off/receive off

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive

Does not send or receive


Examples

This example shows how to configure the local port to not support flow control by the remote port:

Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# flowcontrol receive off

You can verify your settings by entering the show interfaces privileged EXEC command.

Related Commands

Command
Description

show interfaces

Displays the interface settings on the switch, including input and output flow control.


interface port-channel

Use the interface port-channel global configuration command on the switch stack or on a standalone switch to access or create the port-channel logical interface. Use the no form of this command to remove the port-channel.

interface port-channel port-channel-number

no interface port-channel port-channel-number

Syntax Description

port-channel-number

Port-channel number. The range is 1 to 48.


Defaults

No port-channel logical interfaces are defined.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.2(25)SE

The port-channel-number range was changed from 1 to 12 to 1 to 48.


Usage Guidelines

For Layer 2 EtherChannels, you do not have to create a port-channel interface first before assigning a physical port to a channel group. Instead, you can use the channel-group interface configuration command. It automatically creates the port-channel interface when the channel group gets its first physical port. If you create the port-channel interface first, the channel-group-number can be the same as the port-channel-number, or you can use a new number. If you use a new number, the channel-group command dynamically creates a new port channel.

You create Layer 3 port channels by using the interface port-channel command followed by the no switchport interface configuration command. You should manually configure the port-channel logical interface before putting the interface into the channel group.

Only one port channel in a channel group is allowed.


Caution When using a port-channel interface as a routed port, do not assign Layer 3 addresses on the physical ports that are assigned to the channel group.


Caution Do not assign bridge groups on the physical ports in a channel group used as a Layer 3 port-channel interface because it creates loops. You must also disable spanning tree.

Follow these guidelines when you use the interface port-channel command:

If you want to use the Cisco Discovery Protocol (CDP), you must configure it only on the physical port and not on the port-channel interface.

Do not configure a port that is an active member of an EtherChannel as an 802.1x port. If 802.1x is enabled on a not-yet active port of an EtherChannel, the port does not join the EtherChannel.

For a complete list of configuration guidelines, see the "Configuring EtherChannels" chapter in the software configuration guide for this release.

Examples

This example shows how to create a port-channel interface with a port channel number of 5:

Switch(config)# interface port-channel 5

You can verify your setting by entering the show running-config privileged EXEC or show etherchannel channel-group-number detail privileged EXEC command.

Related Commands

Command
Description

channel-group

Assigns an Ethernet port to an EtherChannel group.

show etherchannel

Displays EtherChannel information for a channel.

show running-config

Displays the current operating configuration. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


interface range

Use the interface range global configuration command on the switch stack or on a standalone switch to enter interface range configuration mode and to execute a command on multiple ports at the same time. Use the no form of this command to remove an interface range.

interface range {port-range | macro name}

no interface range {port-range | macro name}

Syntax Description

port-range

Port range. For a list of valid values for port-range, see the "Usage Guidelines" section.

macro name

Specify the name of a macro.


Defaults

This command has no default setting.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

When you enter interface range configuration mode, all interface parameters you enter are attributed to all interfaces within the range.

For VLANs, you can use the interface range command only on existing VLAN switch virtual interfaces (SVIs). To display VLAN SVIs, enter the show running-config privileged EXEC command. VLANs not displayed cannot be used in the interface range command. The commands entered under interface range command are applied to all existing VLAN SVIs in the range.

All configuration changes made to an interface range are saved to NVRAM, but the interface range itself is not saved to NVRAM.

You can enter the interface range in two ways:

Specifying up to five interface ranges

Specifying a previously defined interface-range macro

All interfaces in a range must be the same type; that is, all Fast Ethernet ports, all Gigabit Ethernet ports, all EtherChannel ports, or all VLANs. However, you can define up to five interface ranges with a single command, with each range separated by a comma.

Valid values for port-range type and interface:

vlan vlan-ID - vlan-ID, where VLAN ID is from 1 to 4094

fastethernet stack member/module/{first port} - {last port}, where module is always 0

gigabitethernet stack member/module/{first port} - {last port}, where module is always 0

For physical interfaces:

stack member is the number used to identify the switch within the stack. The number ranges from 1 to 9 and is assigned to the switch the first time the stack member initializes.

module is always 0

the range is type stack member/0/number - number (for example, gigabitethernet1/0/1 - 2)

port-channel port-channel-number - port-channel-number, where port-channel-number is from 1 to 48


Note When you use the interface range command with port channels, the first and last port channel number in the range must be active port channels.


When you define a range, you must enter a space between the first entry and the hyphen (-):

interface range gigabitethernet1/0/1 -2

When you define multiple ranges, you must still enter a space after the first entry and before the comma (,):

interface range fastethernet1/0/1 - 2, gigabitethernet1/0/1 - 2

You cannot specify both a macro and an interface range in the same command.

A single interface can also be specified in port-range (this would make the command similar to the interface interface-id global configuration command).


Note For more information about configuring interface ranges, see the software configuration guide for this release.


Examples

This example shows how to use the interface range command to enter interface range configuration mode to apply commands to two ports:

Switch(config)# interface range gigabitethernet1/0/1 - 2
Switch(config-if-range)#

This example shows how to use a port-range macro macro1 for the same function. The advantage is that you can reuse macro1 until you delete it.

Switch(config)# define interface-range macro1 gigabitethernet1/0/1 - 2
Switch(config)# interface range macro macro1
Switch(config-if-range)#

Related Commands

Command
Description

define interface-range

Creates an interface range macro.

show running-config

Displays the configuration information currently running on the switch. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


interface vlan

Use the interface vlan global configuration command on the switch stack or on a standalone switch to create or access a dynamic switch virtual interface (SVI) and to enter interface configuration mode. Use the no form of this command to delete an SVI.

interface vlan vlan-id

no interface vlan vlan-id

Syntax Description

vlan-id

VLAN number. The range is 1 to 4094.


Defaults

The default VLAN interface is VLAN 1.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

SVIs are created the first time that you enter the interface vlan vlan-id command for a particular vlan. The vlan-id corresponds to the VLAN-tag associated with data frames on an ISL or 802.1Q encapsulated trunk or the VLAN ID configured for an access port.


Note When you create an SVI, it does not become active until it is associated with a physical port.


If you delete an SVI by entering the no interface vlan vlan-id command, the deleted interface is no longer visible in the output from the show interfaces privileged EXEC command.


Note You cannot delete the VLAN 1 interface.


You can reinstate a deleted SVI by entering the interface vlan vlan-id command for the deleted interface. The interface comes back up, but much of the previous configuration will be gone.

The interrelationship between the number of SVIs configured on a switch stack and the number of other features being configured might have an impact on CPU utilization due to hardware limitations. You can use the sdm prefer global configuration command to reallocate system hardware resources based on templates and feature tables. For more information, see the sdm prefer command.

Examples

This example shows how to create a new SVI with VLAN ID 23 and enter interface configuration mode:

Switch(config)# interface vlan 23
Switch(config-if)#

You can verify your setting by entering the show interfaces and show interfaces vlan vlan-id privileged EXEC commands.

Related Commands

Command
Description

show interfaces vlan vlan-id

Displays the administrative and operational status of all interfaces or the specified VLAN.


ip access-group

Use the ip access-group interface configuration command on the switch stack or on a standalone switch to control access to a Layer 2 or Layer 3 interface. Use the no form of this command to remove all access groups or the specified access group from the interface.

ip access-group {access-list-number | name} {in | out}

no ip access-group [access-list-number | name] {in | out}

Syntax Description

access-list-number

The number of the IP access control list (ACL). The range is 1 to 199 or 1300 to 2699.

name

The name of an IP ACL, specified in the ip access-list global configuration command.

in

Specify filtering on inbound packets.

out

Specify filtering on outbound packets. This keyword is valid only on Layer 3 interfaces.


Defaults

No access list is applied to the interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(14)EA1

This command support was extended to Layer 2 interfaces.


Usage Guidelines

You can apply named or numbered standard or extended IP access lists to an interface. To define an access list by name, use the ip access-list global configuration command. To define a numbered access list, use the access list global configuration command. You can used numbered standard access lists ranging from 1 to 99 and 1300 to 1999 or extended access lists ranging from 100 to 199 and 2000 to 2699.

You can use this command to apply an access list to a Layer 2 or Layer 3 interface. However, note these limitations for Layer 2 interfaces (port ACLs):

You can only apply ACLs in the inbound direction; the out keyword is not supported for Layer 2 interfaces.

You can only apply one IP ACL and one MAC ACL per interface.

Layer 2 interfaces do not support logging; if the log keyword is specified in the IP ACL, it is ignored.

An IP ACL applied to a Layer 2 interface only filters IP packets. To filter non-IP packets, use the mac access-group interface configuration command with MAC extended ACLs.

You can use router ACLs, input port ACLs, and VLAN maps on the same switch. However, a port ACL takes precedence over a router ACL or VLAN map.

When an input port ACL is applied to an interface and a VLAN map is applied to a VLAN that the interface is a member of, incoming packets received on ports with the ACL applied are filtered by the port ACL. Other packets are filtered by the VLAN map.

When an input router ACL and input port ACLs exist in an switch virtual interface (SVI), incoming packets received on ports to which a port ACL is applied are filtered by the port ACL. Incoming routed IP packets received on other ports are filtered by the router ACL. Other packets are not filtered.

When an output router ACL and input port ACLs exist in an SVI, incoming packets received on the ports to which a port ACL is applied are filtered by the port ACL. Outgoing routed IP packets are filtered by the router ACL. Other packets are not filtered.

When a VLAN map, input router ACLs, and input port ACLs exist in an SVI, incoming packets received on the ports to which a port ACL is applied are only filtered by the port ACL. Incoming routed IP packets received on other ports are filtered by both the VLAN map and the router ACL. Other packets are filtered only by the VLAN map.

When a VLAN map, output router ACLs, and input port ACLs exist in an SVI, incoming packets received on the ports to which a port ACL is applied are only filtered by the port ACL. Outgoing routed IP packets are filtered by both the VLAN map and the router ACL. Other packets are filtered only by the VLAN map.

You can apply IP ACLs to both outbound or inbound Layer 3 interfaces.

A Layer 3 interface can have one IP ACL applied in each direction.

You can configure only one VLAN map and one router ACL in each direction (input/output) on a VLAN interface.

For standard inbound access lists, after the switch receives a packet, it checks the source address of the packet against the access list. IP extended access lists can optionally check other fields in the packet, such as the destination IP address, protocol type, or port numbers. If the access list permits the packet, the switch continues to process the packet. If the access list denies the packet, the switch discards the packet. If the access list has been applied to a Layer 3 interface, discarding a packet (by default) causes the generation of an Internet Control Message Protocol (ICMP) Host Unreachable message. ICMP Host Unreachable messages are not generated for packets discarded on a Layer 2 interface.

For standard outbound access lists, after receiving a packet and sending it to a controlled interface, the switch checks the packet against the access list. If the access list permits the packet, the switch sends the packet. If the access list denies the packet, the switch discards the packet and, by default, generates an ICMP Host Unreachable message.

If the specified access list does not exist, all packets are passed.

Examples

This example shows how to apply IP access list 101 to inbound packets on a port:

Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# ip access-group 101 in

You can verify your settings by entering the show ip interface, show access-lists, or show ip access-lists privileged EXEC command.

Related Commands

Command
Description

access list

Configures a numbered ACL. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands

ip access-list

Configures a named ACL. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.

show access-lists

Displays ACLs configured on the switch.

show ip access-lists

Displays IP ACLs configured on the switch. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.

show ip interface

Displays information about interface status and configuration. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.


ip address

Use the ip address interface configuration command on the switch stack or on a standalone switch to set an IP address for the Layer 2 switch or an IP address for each switch virtual interface (SVI) or routed port on the Layer 3 switch. Use the no form of this command to remove an IP address or to disable IP processing.

ip address ip-address subnet-mask [secondary]

no ip address [ip-address subnet-mask] [secondary]

Syntax Description

ip-address

IP address.

subnet-mask

Mask for the associated IP subnet.

secondary

(Optional) Specifies that the configured address is a secondary IP address. If this keyword is omitted, the configured address is the primary IP address.


Defaults

No IP address is defined.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

If you remove the switch IP address through a Telnet session, your connection to the switch will be lost.

Hosts can find subnet masks using the Internet Control Message Protocol (ICMP) Mask Request message. Routers respond to this request with an ICMP Mask Reply message.

You can disable IP processing on a particular interface by removing its IP address with the no ip address command. If the switch detects another host using one of its IP addresses, it will send an error message to the console.

You can use the optional keyword secondary to specify an unlimited number of secondary addresses. Secondary addresses are treated like primary addresses, except the system never generates datagrams other than routing updates with secondary source addresses. IP broadcasts and ARP requests are handled properly, as are interface routes in the IP routing table.


Note If any router on a network segment uses a secondary address, all other devices on that same segment must also use a secondary address from the same network or subnet. Inconsistent use of secondary addresses on a network segment can very quickly cause routing loops.


When you are routing Open Shortest Path First (OSPF), ensure that all secondary addresses of an interface fall into the same OSPF area as the primary addresses.

If your switch receives its IP address from a Bootstrap Protocol (BOOTP) or a DHCP server and you remove the switch IP address by using the no ip address command, IP processing is disabled, and the BOOTP or the DHCP server cannot reassign the address.

A Layer 3 switch can have an IP address assigned to each routed port and SVI. The number of routed ports and SVIs that you can configure is not limited by software; however, the interrelationship between this number and the number of other features being configured might have an impact on CPU utilization due to hardware limitations. You can use the sdm prefer global configuration command to reallocate system hardware resources based on templates and feature tables. For more information, see the sdm prefer command.

Examples

This example shows how to configure the IP address for the Layer 2 switch on a subnetted network:

Switch(config)# interface vlan 1
Switch(config-if)# ip address 172.20.128.2 255.255.255.0

This example shows how to configure the IP address for a port on the Layer 3 switch:

Switch(config)# ip multicast-routing
Switch(config)# interface gigabitethernet6/0/1
Switch(config-if)# no switchport
Switch(config-if)# ip address 172.20.128.2 255.255.255.0

You can verify your settings by entering the show running-config privileged EXEC command.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


ip arp inspection filter vlan

Use the ip arp inspection filter vlan global configuration command on the switch stack or on a standalone switch to permit or deny Address Resolution Protocol (ARP) requests and responses from a host configured with a static IP address when dynamic ARP inspection is enabled. Use the no form of this command to return to the default settings.

ip arp inspection filter arp-acl-name vlan vlan-range [static]

no ip arp inspection filter arp-acl-name vlan vlan-range [static]

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

arp-acl-name

ARP access control list (ACL) name.

vlan-range

VLAN number or range.

You can specify a single VLAN identified by VLAN ID number, a range of VLANs separated by a hyphen, or a series of VLANs separated by a comma. The range is 1 to 4094.

static

(Optional) Specify static to treat implicit denies in the ARP ACL as explicit denies and to drop packets that do not match any previous clauses in the ACL. DHCP bindings are not used.

If you do not specify this keyword, it means that there is no explicit deny in the ACL that denies the packet, and DHCP bindings determine whether a packet is permitted or denied if the packet does not match any clauses in the ACL.


Defaults

No defined ARP ACLs are applied to any VLAN.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

When an ARP ACL is applied to a VLAN for dynamic ARP inspection, only the ARP packets with IP-to-MAC address bindings are compared against the ACL. If the ACL permits a packet, the switch forwards it. All other packet types are bridged in the ingress VLAN without validation.

If the switch denies a packet because of an explicit deny statement in the ACL, the packet is dropped. If the switch denies a packet because of an implicit deny statement, the packet is then compared against the list of DHCP bindings (unless the ACL is static, which means that packets are not compared against the bindings).

Use the arp access-list acl-name global configuration command to define the ARP ACL or to add clauses to the end of a predefined list.

Examples

This example shows how to apply the ARP ACL static-hosts to VLAN 1 for dynamic ARP inspection:

Switch(config)# ip arp inspection filter static-hosts vlan 1

You can verify your settings by entering the show ip arp inspection vlan 1 privileged EXEC command.

Related Commands

Command
Description

arp access-list

Defines an ARP ACL.

deny (ARP access-list configuration)

Denies an ARP packet based on matches against the DHCP bindings.

permit (ARP access-list configuration)

Permits an ARP packet based on matches against the DHCP bindings.

show arp access-list

Displays detailed information about ARP access lists.

show ip arp inspection vlan vlan-range

Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.


ip arp inspection limit

Use the ip arp inspection limit interface configuration command on the switch stack or on a standalone switch to limit the rate of incoming Address Resolution Protocol (ARP) requests and responses on an interface. It prevents dynamic ARP inspection from using all of the switch resources if a denial-of-service attack occurs. Use the no form of this command to return to the default settings.

ip arp inspection limit {rate pps [burst interval seconds] | none}

no ip arp inspection limit

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

rate pps

Specify an upper limit for the number of incoming packets processed per second. The range is 0 to 2048 packets per second (pps).

burst interval seconds

(Optional) Specify the consecutive interval in seconds, over which the interface is monitored for a high rate of ARP packets.The range is 1 to 15 seconds.

none

Specify no upper limit for the rate of incoming ARP packets that can be processed.


Defaults

The rate is 15 pps on untrusted interfaces, assuming that the network is a switched network with a host connecting to as many as 15 new hosts per second.

The rate is unlimited on all trusted interfaces.

The burst interval is 1 second.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

The rate applies to both trusted and untrusted interfaces. Configure appropriate rates on trunks to process packets across multiple dynamic ARP inspection-enabled VLANs, or use the none keyword to make the rate unlimited.

After a switch receives more than the configured rate of packets every second consecutively over a number of burst seconds, the interface is placed into an error-disabled state.

Unless you explicitly configure a rate limit on an interface, changing the trust state of the interface also changes its rate limit to the default value for that trust state. After you configure the rate limit, the interface retains the rate limit even when its trust state is changed. If you enter the no ip arp inspection limit interface configuration command, the interface reverts to its default rate limit.

You should configure trunk ports with higher rates to reflect their aggregation. When the rate of incoming packets exceeds the user-configured rate, the switch places the interface into an error-disabled state. The error-disable recovery feature automatically removes the port from the error-disabled state according to the recovery setting.

The rate limit is calculated separately on each switch in a switch stack. For a cross-stack EtherChannel, this means that the actual rate limit might be higher than the configured value. For example, if you set the rate limit to 30 pps on an EtherChannel that has one port on switch 1 and one port on switch 2, each port can receive packets at 29 pps without causing the EtherChannel to become error-disabled.

The rate of incoming ARP packets on EtherChannel ports equals the sum of the incoming rate of ARP packets from all the channel members. Configure the rate limit for EtherChannel ports only after examining the rate of incoming ARP packets on all the channel members.

Examples

This example shows how to limit the rate of incoming ARP requests on a port to 25 pps and to set the interface monitoring interval to 5 consecutive seconds:

Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# ip arp inspection limit rate 25 burst interval 5

You can verify your settings by entering the show ip arp inspection interfaces interface-id privileged EXEC command.

Related Commands

Command
Description

show ip arp inspection interfaces

Displays the trust state and the rate limit of ARP packets for the specified interface or all interfaces.


ip arp inspection log-buffer

Use the ip arp inspection log-buffer global configuration command on the switch stack or on a standalone switch to configure the dynamic Address Resolution Protocol (ARP) inspection logging buffer. Use the no form of this command to return to the default settings.

ip arp inspection log-buffer {entries number | logs number interval seconds}

no ip arp inspection log-buffer {entries | logs}

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

entries number

Number of entries to be logged in the buffer. The range is 0 to 1024.

logs number interval seconds

Number of entries needed in the specified interval to generate system messages.

For logs number, the range is 0 to 1024. A 0 value means that the entry is placed in the log buffer, but a system message is not generated.

For interval seconds, the range is 0 to 86400 seconds (1 day). A 0 value means that a system message is immediately generated (and the log buffer is always empty).


Defaults

When dynamic ARP inspection is enabled, denied or dropped ARP packets are logged.

The number of log entries is 32.

The number of system messages is limited to 5 per second.

The logging-rate interval is 1 second.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

A value of 0 is not allowed for both the logs and the interval keywords.

The logs and interval settings interact. If the logs number X is greater than interval seconds Y, X divided by Y (X/Y) system messages are sent every second. Otherwise, one system message is sent every Y divided by X (Y/X) seconds. For example, if the logs number is 20 and the interval seconds is 4, the switch generates system messages for five entries every second while there are entries in the log buffer.

A log buffer entry can represent more than one packet. For example, if an interface receives many packets on the same VLAN with the same ARP parameters, the switch combines the packets as one entry in the log buffer and generates a system message as a single entry.

If the log buffer overflows, it means that a log event does not fit into the log buffer, and the output display for the show ip arp inspection log privileged EXEC command is affected. A -- in the output display appears in place of all data except the packet count and the time. No other statistics are provided for the entry. If you see this entry in the display, increase the number of entries in the log buffer, or increase the logging rate.

The log buffer configuration applies to each stack member in a switch stack. Each stack member has the specified logs number entries and generates system messages at the configured rate. For example, if the interval (rate) is one entry per second, up to five system messages are generated per second in a five-member switch stack.

Examples

This example shows how to configure the logging buffer to hold up to 45 entries:

Switch(config)# ip arp inspection log-buffer entries 45

This example shows how to configure the logging rate to 20 log entries per 4 seconds. With this configuration, the switch generates system messages for five entries every second while there are entries in the log buffer.

Switch(config)# ip arp inspection log-buffer logs 20 interval 4

You can verify your settings by entering the show ip arp inspection log privileged EXEC command.

Related Commands

Command
Description

arp access-list

Defines an ARP access control list (ACL).

clear ip arp inspection log

Clears the dynamic ARP inspection log buffer.

ip arp inspection vlan logging

Controls the type of packets that are logged per VLAN.

show ip arp inspection log

Displays the configuration and contents of the dynamic ARP inspection log buffer.


ip arp inspection trust

Use the ip arp inspection trust interface configuration command on the switch stack or on a standalone switch to configure an interface trust state that determines which incoming Address Resolution Protocol (ARP) packets are inspected. Use the no form of this command to return to the default setting.

ip arp inspection trust

no ip arp inspection trust

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

This command has no arguments or keywords.

Defaults

The interface is untrusted.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

The switch does not check ARP packets that it receives on the trusted interface; it simply forwards the packets.

For untrusted interfaces, the switch intercepts all ARP requests and responses. It verifies that the intercepted packets have valid IP-to-MAC address bindings before updating the local cache and before forwarding the packet to the appropriate destination. The switch drops invalid packets and logs them in the log buffer according to the logging configuration specified with the ip arp inspection vlan logging global configuration command.

Examples

This example shows how to configure a port to be trusted:

Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# ip arp inspection trust 

You can verify your setting by entering the show ip arp inspection interfaces interface-id privileged EXEC command.

Related Commands

Command
Description

ip arp inspection log-buffer

Configures the dynamic ARP inspection logging buffer.

show ip arp inspection interfaces

Displays the trust state and the rate limit of ARP packets for the specified interface or all interfaces.

show ip arp inspection log

Displays the configuration and contents of the dynamic ARP inspection log buffer.


ip arp inspection validate

Use the ip arp inspection validate global configuration command on the switch stack or on a standalone switch to perform specific checks for dynamic Address Resolution Protocol (ARP) inspection. Use the no form of this command to return to the default settings.

ip arp inspection validate {[src-mac] [dst-mac] [ip]}

no ip arp inspection validate [src-mac] [dst-mac] [ip]

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

src-mac

Compare the source MAC address in the Ethernet header against the sender MAC address in the ARP body. This check is performed on both ARP requests and responses.

When enabled, packets with different MAC addresses are classified as invalid and are dropped.

dst-mac

Compare the destination MAC address in the Ethernet header against the target MAC address in ARP body. This check is performed for ARP responses.

When enabled, packets with different MAC addresses are classified as invalid and are dropped.

ip

Compare the ARP body for invalid and unexpected IP addresses. Addresses include 0.0.0.0, 255.255.255.255, and all IP multicast addresses.

Sender IP addresses are compared in all ARP requests and responses. Target IP addresses are checked only in ARP responses.


Defaults

No checks are performed.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

You must specify at least one of the keywords. Each command overrides the configuration of the previous command; that is, if a command enables src-mac and dst-mac validations, and a second command enables IP validation only, the src-mac and dst-mac validations are disabled as a result of the second command.

If you first specify the src-mac keyword, you also can specify the dst-mac and ip keywords. If you first specify the ip keyword, no other keywords can be specified.

The no form of the command disables only the specified checks. If none of the options are enabled, all checks are disabled.

Examples

This example show how to enable source MAC validation:

Switch(config)# ip arp inspection validate src-mac 

You can verify your setting by entering the show ip arp inspection vlan vlan-range privileged EXEC command.

Related Commands

Command
Description

show ip arp inspection vlan vlan-range

Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.


ip arp inspection vlan

Use the ip arp inspection vlan global configuration command on the switch stack or on a standalone switch to enable dynamic Address Resolution Protocol (ARP) inspection on a per-VLAN basis. Use the no form of this command to return to the default setting.

ip arp inspection vlan vlan-range

no ip arp inspection vlan vlan-range

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

vlan-range

VLAN number or range.

You can specify a single VLAN identified by VLAN ID number, a range of VLANs separated by a hyphen, or a series of VLANs separated by a comma. The range is 1 to 4094.


Defaults

ARP inspection is disabled on all VLANs.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

You must specify the VLANs on which to enable dynamic ARP inspection.

Dynamic ARP inspection is supported on access ports, trunk ports, EtherChannel ports, and private VLAN ports.

Examples

This example shows how to enable dynamic ARP inspection on VLAN 1:

Switch(config)# ip arp inspection vlan 1

You can verify your setting by entering the show ip arp inspection vlan vlan-range privileged EXEC command.

Related Commands

Command
Description

arp access-list

Defines an ARP access control list (ACL).

show ip arp inspection vlan vlan-range

Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.


ip arp inspection vlan logging

Use the ip arp inspection vlan logging global configuration command on the switch stack or on a standalone switch to control the type of packets that are logged per VLAN. Use the no form of this command to disable this logging control.

ip arp inspection vlan vlan-range logging {acl-match {matchlog | none} | dhcp-bindings {all | none | permit}}

no ip arp inspection vlan vlan-range logging {acl-match | dhcp-bindings}

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

vlan-range

Specify the VLANs configured for logging.

You can specify a single VLAN identified by VLAN ID number, a range of VLANs separated by a hyphen, or a series of VLANs separated by a comma. The range is 1 to 4094.

acl-match {matchlog | none}

Specify that the logging of packets is based on access control list (ACL) matches.

The keywords have these meanings:

matchlog—Log packets based on the logging configuration specified in the access control entries (ACE). If you specify the matchlog keyword in this command and the log keyword in the permit or deny ARP access-list configuration command, Address Resolution Protocol (ARP) packets permitted or denied by the ACL are logged.

none—Do not log packets that match ACLs.

dhcp-bindings {permit | all | none}

Specify the logging of packets is based on Dynamic Host Configuration Protocol (DHCP) binding matches.

The keywords have these meanings:

all—Log all packets that match DHCP bindings.

none—Do not log packets that match DHCP bindings.

permit—Log DHCP-binding permitted packets.


Defaults

All denied or all dropped packets are logged.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

The term logged means that the entry is placed into the log buffer and that a system message is generated.

The acl-match and dhcp-bindings keywords merge with each other; that is, when you configure an ACL match, the DHCP bindings configuration is not disabled. Use the no form of the command to reset the logging criteria to their defaults. If neither option is specified, all types of logging are reset to log when ARP packets are denied. These are the options:

acl-match—Logging on ACL matches is reset to log on deny.

dhcp-bindings—Logging on DHCP binding matches is reset to log on deny.

If neither the acl-match or the dhcp-bindings keywords are specified, all denied packets are logged.

The implicit deny at the end of an ACL does not include the log keyword. This means that when you use the static keyword in the ip arp inspection filter vlan global configuration command, the ACL overrides the DHCP bindings. Some denied packets might not be logged unless you explicitly specify the deny ip any mac any log ACE at the end of the ARP ACL.

Examples

This example shows how to configure ARP inspection on VLAN 1 to log packets that match the permit commands in the ACL:

Switch(config)# arp access-list test1
Switch(config-arp-nacl)# permit request ip any mac any log
Switch(config-arp-nacl)# permit response ip any any mac any any log
Switch(config-arp-nacl)# exit
Switch(config)# ip arp inspection vlan 1 logging acl-match matchlog 

You can verify your settings by entering the show ip arp inspection vlan vlan-range privileged EXEC command.

Related Commands

Command
Description

arp access-list

Defines an ARP ACL.

clear ip arp inspection log

Clears the dynamic ARP inspection log buffer.

ip arp inspection log-buffer

Configures the dynamic ARP inspection logging buffer.

show ip arp inspection log

Displays the configuration and contents of the dynamic ARP inspection log buffer.

show ip arp inspection vlan vlan-range

Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.


ip dhcp snooping

Use the ip dhcp snooping global configuration command on the switch stack or on a standalone switch to globally enable DHCP snooping. Use the no form of this command to return to the default setting.

ip dhcp snooping

no ip dhcp snooping

Syntax Description

This command has no arguments or keywords.

Defaults

DHCP snooping is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

For any DHCP snooping configuration to take effect, you must globally enable DHCP snooping.

DHCP snooping is not active until you enable snooping on a VLAN by using the ip dhcp snooping vlan vlan-id global configuration command.

Examples

This example shows how to enable DHCP snooping:

Switch(config)# ip dhcp snooping

You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.

Related Commands

Command
Description

ip dhcp snooping vlan

Enables DHCP snooping on a VLAN.

show ip dhcp snooping

Displays the DHCP snooping configuration.

show ip dhcp snooping binding

Displays the DHCP snooping binding information.


ip dhcp snooping binding

Use the ip dhcp snooping binding privileged EXEC command on the switch stack or on a standalone switch to configure the DHCP snooping binding database and to add binding entries to the database. Use the no form of this command to delete entries from the binding database.

ip dhcp snooping binding mac-address vlan vlan-id ip-address interface interface-id expiry seconds

no ip dhcp snooping binding mac-address vlan vlan-id ip-address interface interface-id

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

mac-address

Specify a MAC address.

vlan vlan-id

Specify a VLAN number. The range is from 1 to 4904.

ip-address

Specify an IP address.

interface interface-id

Specify an interface on which to add or delete a binding entry.

expiry seconds

Specify the interval (in seconds) after which the binding entry is no longer valid. The range is from 1 to 4294967295.


Defaults

No default database is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

In the DHCP snooping binding database, each database entry, also referred to a binding, has an IP address, an associated MAC address, the lease time (in hexadecimal format), the interface to which the binding applies, and the VLAN to which the interface belongs. The database can have up to 8192 bindings.

When a switch learns new bindings or it loses bindings, the switch updates the entries in the database and in the binding file at a configured location. The frequency at which the database and the file are updated is based on a configurable delay, and the updates are batched. You can configure this delay by using the ip dhcp snooping database write-delay seconds global configuration command.

Use the show ip dhcp snooping binding privileged EXEC command to display only the dynamically configured bindings. Use the show ip source binding privileged EXEC command to display the dynamically and statically configured bindings.

Examples

This example shows how to generate a DHCP binding configuration with an expiration time of 1000 seconds on a port in VLAN 1:

Switch# ip dhcp snooping binding 0001.1234.1234 vlan 1 172.20.50.5 interface 
gigabitethernet1/0/1 expiry 1000

You can verify your settings by entering the show ip dhcp snooping binding or the show ip dhcp source binding privileged EXEC command.

Related Commands

Command
Description

ip dhcp snooping

Enables DHCP snooping on a VLAN.

show ip dhcp snooping binding

Displays the dynamically configured bindings in the DHCP snooping binding database and the configuration information.

show ip source binding

Displays the dynamically and statically configured bindings in the DHCP snooping binding database.


ip dhcp snooping database

Use the ip dhcp snooping database global configuration command on the switch stack or on a standalone switch to configure the DHCP snooping binding database agent or the binding file. Use the no form of this command to delete the agent or file specified by the URL, to reset the timeout value, or to reset the write-delay value.

ip dhcp snooping database {{flash[number]:/filename | ftp://user:password@host/filename | http://[[username:password]@]{hostname | host-ip}[/directory]/image-name.tar | rcp://user@host/filename | tftp://host/filename} | timeout seconds | write-delay seconds}

no ip dhcp snooping database [timeout | write-delay]

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

flash[number]:/filename

Specify that the database agent or the binding file is in the flash memory.

(Optional) Use the number parameter to specify the stack member number of the stack master. The range for number is 1 to 9.

ftp://user:password@host/filename

Specify that the database agent or the binding file is on an FTP server.

http://[[username:password]@]
{hostname | host-ip}[/directory]
/image-name
.tar

Specify that the database agent or the binding file is on an FTP server.

rcp://user@host/filename

Specify that the database agent or the binding file is on a Remote Control Protocol (RCP) server.

tftp://host/filename

Specify that the database agent or the binding file is on a TFTP server.

timeout seconds

Specify (in seconds) when to stop the database transfer process after the DHCP snooping binding database changes.

The default is 300 seconds. The range is from 0 to 86400. Use 0 to define an infinite duration.

write-delay seconds

Specify (in seconds) the duration for which the transfer should be delayed after the binding database changes. The default is 300 seconds. The range is from 15 to 86400.


Defaults

The URL for the database agent or binding file is not defined.

The timeout value is 300 seconds (5 minutes).

The write-delay value is 300 seconds (5 minutes).

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

The DHCP snooping binding database can have up to 8192 bindings.

To ensure that the lease time in the database is accurate, we recommend that Network Time Protocol (NTP) is enabled and configured for these features:

NTP authentication

NTP peer and server associations

NTP broadcast service

NTP access restrictions

NTP packet source IP address

If NTP is not configured, the switch writes binding changes to the binding file only when the switch system clock is synchronized with NTP.

Because both NVRAM and the flash memory have limited storage capacity, we recommend that you store a binding file on a TFTP server. You must create an empty file at the configured URL on network-based URLs (such as TFTP and FTP) before the switch can write bindings to the binding file at that URL for the first time.

Use the ip dhcp snooping database flash[number]:/filename command to save the DHCP snooping binding database in the stack master NVRAM. The database is not saved in a stack member NVRAM.

Use the no ip dhcp snooping database command to delete the agent or file specified by the URL.

Use the no ip dhcp snooping database timeout command to reset the timeout value.

Use the no ip dhcp snooping database write-delay command to reset the write-delay value.

Examples

This example shows how to store a binding file at an IP address of 10.1.1.1 that is in a directory called directory. A file named file must be present on the TFTP server.

Switch(config)# ip dhcp snooping database tftp://10.1.1.1/directory/file

This example shows how to store a binding file called file01.txt in the stack master NVRAM.

Switch(config)# ip dhcp snooping database flash:file01.text

You can verify your settings by entering the show ip dhcp snooping database privileged EXEC command.

Related Commands

Command
Description

ip dhcp snooping

Enables DHCP snooping on a VLAN.

ip dhcp snooping binding

Configures the DHCP snooping binding database.

show ip dhcp snooping database

Displays the status of DHCP snooping database agent.


ip dhcp snooping information option

Use the ip dhcp snooping information option global configuration command on the switch stack or on a standalone switch to enable DHCP option-82 data insertion. Use the no form of this command to disable DHCP option-82 data insertion.

ip dhcp snooping information option

no ip dhcp snooping information option

Syntax Description

This command has no arguments or keywords.

Defaults

DHCP option-82 data insertion is enabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

You must globally enable DHCP snooping by using the ip dhcp snooping global configuration command for any DHCP snooping configuration to take effect.

When the option-82 feature is enabled and a switch receives a DHCP request from a host, it adds the option-82 information in the packet. The option-82 information contains the switch MAC address (the remote ID suboption) and the port identifier, vlan-mod-port, from which the packet is received (circuit ID suboption). The switch forwards the DHCP request that includes the option-82 field to the DHCP server.

When the DHCP server receives the packet, it can use the remote ID, the circuit ID, or both to assign IP addresses and implement policies, such as restricting the number of IP addresses that can be assigned to a single remote ID or a circuit ID. Then the DHCP server echoes the option-82 field in the DHCP reply.

The DHCP server unicasts the reply to the switch if the request was relayed to the server by the switch. When the client and server are on the same subnet, the server broadcasts the reply. The switch inspects the remote ID and possibly the circuit ID fields to verify that it originally inserted the option-82 data. The switch removes the option-82 field and forwards the packet to the switch port that connects to the DHCP host that sent the DHCP request.

Examples

This example shows how to enable DHCP option-82 data insertion:

Switch(config)# ip dhcp snooping information option

You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.

Related Commands

Command
Description

show ip dhcp snooping

Displays the DHCP snooping configuration.

show ip dhcp snooping binding

Displays the DHCP snooping binding information.


ip dhcp snooping information option allowed-untrusted

Use the ip dhcp snooping information option allowed-untrusted global configuration command on an aggregation switch to configure it to accept DHCP packets with option-82 information from an edge switch. Use the no form of this command to configure the switch to drop these packets from the edge switch.

ip dhcp snooping information option allowed-untrusted

no ip dhcp snooping information option allowed-untrusted


Note Do not enter the ip dhcp snooping information option allowed-untrusted command on an aggregation switch to which an untrusted device is connected. If you enter this command, an untrusted device might spoof the option-82 information.


Syntax Description

This command has no arguments or keywords.

Defaults

The switch drops DHCP packets with option-82 information from an edge switch.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SEA

This command was introduced.


Usage Guidelines

You might want an edge switch to which a host is connected to insert DHCP option-82 information at the edge of your network. You might also want to enable DHCP security features, such as DHCP snooping, IP source guard, or dynamic Address Resolution Protocol (ARP) inspection, on an aggregation switch. However, if DHCP snooping is enabled on the aggregation switch, the switch drops packets with option-82 information that are received on an untrusted interface and does not learn DHCP snooping bindings for connected devices on a trusted interface.

If the edge switch to which a host is connected inserts option-82 information and you want to use DHCP snooping on an aggregation switch, enter the ip dhcp snooping information option allowed-untrusted command on the aggregation switch. The aggregation switch can learn the bindings for a host even though the aggregation switch receives DHCP snooping packets on an untrusted interface. You can also enable DHCP security features on the aggregation switch. The port on the edge switch to which the aggregation switch is connected must be configured as a trusted interface.

Examples

This example shows how to configure an access switch to not check the option-82 information in untrusted packets from an edge switch and to accept the packets:

Switch(config)# ip dhcp snooping information option allowed-untrusted

You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.

Related Commands

Command
Description

show ip dhcp snooping

Displays the DHCP snooping configuration.

show ip dhcp snooping binding

Displays the DHCP snooping binding information.


ip dhcp snooping limit rate

Use the ip dhcp snooping limit rate interface configuration command on the switch stack or on a standalone switch to configure the number of DHCP messages an interface can receive per second. Use the no form of this command to return to the default setting.

ip dhcp snooping limit rate rate

no ip dhcp snooping limit rate

Syntax Description

rate

Number of DHCP messages an interface can receive per second. The range is 1 to 2048.


Defaults

DHCP snooping rate limiting is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.2(18)SE

The range was changed to 1 to 2048.


Usage Guidelines

Normally, the rate limit applies to untrusted interfaces. If you want to configure rate limiting for trusted interfaces, keep in mind that trusted interfaces might aggregate DHCP traffic on multiple VLANs (some of which might not be snooped) in the switch, and you will need to adjust the interface rate limits to a higher value.

If the rate limit is exceeded, the interface is error-disabled. If you enabled error recovery by entering the errdisable recovery dhcp-rate-limit global configuration command, the interface retries the operation again when all the causes have timed out. If the error-recovery mechanism is not enabled, the interface stays in the error-disabled state until you enter the shutdown and no shutdown interface configuration commands.

Examples

This example shows how to set a message rate limit of 150 messages per second on an interface:

Switch(config-if)# ip dhcp snooping limit rate 150

You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.

Related Commands

Command
Description

errdisable recovery

Configures the recover mechanism.

show ip dhcp snooping

Displays the DHCP snooping configuration.

show ip dhcp snooping binding

Displays the DHCP snooping binding information.


ip dhcp snooping trust

Use the ip dhcp snooping trust interface configuration command on the switch stack or on a standalone switch to configure a port as trusted for DHCP snooping purposes. Use the no form of this command to return to the default setting.

ip dhcp snooping trust

no ip dhcp snooping trust

Syntax Description

This command has no arguments or keywords.

Defaults

DHCP snooping trust is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

Configure as trusted ports those that are connected to a DHCP server or to other switches or routers. Configure as untrusted ports those that are connected to DHCP clients.

Examples

This example shows how to enable DHCP snooping trust on a port:

Switch(config-if)# ip dhcp snooping trust

You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.

Related Commands

Command
Description

show ip dhcp snooping

Displays the DHCP snooping configuration.

show ip dhcp snooping binding

Displays the DHCP snooping binding information.


ip dhcp snooping verify

Use the ip dhcp snooping verify global configuration command on the switch stack or on a standalone switch to configure the switch to verify on an untrusted port that the source MAC address in a DHCP packet matches the client hardware address. Use the no form of this command to configure the switch to not verify the MAC addresses.

ip dhcp snooping verify mac-address

no ip dhcp snooping verify mac-address

Syntax Description

This command has no arguments or keywords.

Defaults

The switch verifies the source MAC address in a DHCP packet that is received on untrusted ports matches the client hardware address in the packet.

Command Modes

Global configuration

Command History

Release
Modification

12.2(18)SE

This command was introduced.


Usage Guidelines

In a service-provider network, when a switch receives a packet from a DHCP client on an untrusted port, it automatically verifies that the source MAC address and the DHCP client hardware address match. If the addresses match, the switch forwards the packet. If the addresses do not match, the switch drops the packet.

Examples

This example shows how to disable the MAC address verification:

Switch(config)# no ip dhcp snooping verify mac-address

You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.

Related Commands

Command
Description

show ip dhcp snooping

Displays the DHCP snooping configuration.


ip dhcp snooping vlan

Use the ip dhcp snooping vlan global configuration command on the switch stack or on a standalone switch to enable DHCP snooping on a VLAN. Use the no form of this command to disable DHCP snooping on a VLAN.

ip dhcp snooping vlan vlan-range

no ip dhcp snooping vlan vlan-range

Syntax Description

vlan vlan-range

Specify a VLAN ID or a range of VLANs on which to enable DHCP snooping. The range is 1 to 4094.

You can enter a single VLAN ID identified by VLAN ID number, a series of VLAN IDs separated by commas, a range of VLAN IDs separated by hyphens, or a range of VLAN IDs separated by entering the starting and ending VLAN IDs separated by a space.


Defaults

DHCP snooping is disabled on all VLANs.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

You must first globally enable DHCP snooping before enabling DHCP snooping on a VLAN.

Examples

This example shows how to enable DHCP snooping on VLAN 10:

Switch(config)# ip dhcp snooping vlan 10

You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.

Related Commands

Command
Description

show ip dhcp snooping

Displays the DHCP snooping configuration.

show ip dhcp snooping binding

Displays the DHCP snooping binding information.


ip igmp filter

Use the ip igmp filter interface configuration command on the switch stack or on a standalone switch to control whether or not all hosts on a Layer 2 interface can join one or more IP multicast groups by applying an Internet Group Management Protocol (IGMP) profile to the interface. Use the no form of this command to remove the specified profile from the interface.

ip igmp filter profile number

no ip igmp filter

Syntax Description

profile number

The IGMP profile number to be applied. The range is 1 to 4294967295.


Defaults

No IGMP filters are applied.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You can apply IGMP filters only to Layer 2 physical interfaces; you cannot apply IGMP filters to routed ports, switch virtual interfaces (SVIs), or ports that belong to an EtherChannel group.

An IGMP profile can be applied to one or more switch port interfaces, but one port can have only one profile applied to it.

Examples

This example shows how to apply IGMP profile 22 to a port.

Switch(config)# interface gigabitethernet1/0/2
Switch(config-if)# ip igmp filter 22

You can verify your setting by using the show running-config privileged EXEC command and by specifying an interface.

Related Commands

Command
Description

ip igmp profile

Configures the specified IGMP profile number.

show ip igmp profile

Displays the characteristics of the specified IGMP profile.

show running-config interface interface-id

Displays the running configuration on the switch interface, including the IGMP profile (if any) that is applied to an interface. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


ip igmp max-groups

Use the ip igmp max-groups interface configuration command on the switch stack or on a standalone switch to set the maximum number of Internet Group Management Protocol (IGMP) groups that a Layer 2 interface can join or to configure the IGMP throttling action when the maximum number of entries is in the forwarding table. Use the no form of this command to set the maximum back to the default, which is to have no maximum limit, or to return to the default throttling action, which is to drop the report.

ip igmp max-groups {number | action {deny | replace}}

no ip igmp max-groups {number | action}

Syntax Description

number

The maximum number of IGMP groups that an interface can join. The range is 0 to 4294967294. The default is no limit.

action deny

When the maximum number of entries is in the IGMP snooping forwarding table, drop the next IGMP join report. This is the default action.

action replace

When the maximum number of entries is in the IGMP snooping forwarding table, remove an randomly-selected entry in the forwarding table and add an entry for the next IGMP group.


Defaults

The default maximum number of groups is no limit.

After the switch learns the maximum number of IGMP group entries on an interface, the default throttling action is to drop the next IGMP report that the interface receives and to not add an entry for the IGMP group to the interface.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(19)EA1

The action {deny | replace} keywords were added.


Usage Guidelines

You can use this command only on Layer 2 physical interfaces and on logical EtherChannel interfaces. You cannot set IGMP maximum groups for routed ports, switch virtual interfaces (SVIs), or ports that belong to an EtherChannel group.

Follow these guidelines when configuring the IGMP throttling action:

If you configure the throttling action as deny and set the maximum group limitation, the entries that were previously in the forwarding table are not removed but are aged out. After these entries are aged out, when the maximum number of entries is in the forwarding table, the switch drops the next IGMP report received on the interface.

If you configure the throttling action as replace and set the maximum group limitation, the entries that were previously in the forwarding table are removed. When the maximum number of entries is in the forwarding table, the switch deletes a randomly-selected entry and adds an entry for the next IGMP report received on the interface.

When the maximum group limitation is set to the default (no maximum), entering the ip igmp max-groups {deny | replace} command has no effect.

Examples

This example shows how to limit to 25 the number of IGMP groups that a port can join.

Switch(config)# interface gigabitethernet1/0/2
Switch(config-if)# ip igmp max-groups 25

This example shows how to configure the switch to delete a random IGMP group in the forwarding table and to add an entry for the IGMP group when the maximum number of entries is in the forwarding table:

Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# ip igmp max-groups action replace

You can verify your setting by using the show running-config privileged EXEC command and by specifying an interface.

Related Commands

Command
Description

show running-config interface interface-id

Displays the running configuration on the switch interface, including the maximum number of IGMP groups that an interface can join and the throttling action. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


ip igmp profile

Use the ip igmp profile global configuration command on the switch stack or on a standalone switch to create an Internet Group Management Protocol (IGMP) profile and enter IGMP profile configuration mode. From this mode, you can specify the configuration of the IGMP profile to be used for filtering IGMP membership reports from a switchport. Use the no form of this command to delete the IGMP profile.

ip igmp profile profile number

no ip igmp profile profile number

Syntax Description

profile number

The IGMP profile number being configured. The range is 1 to 4294967295.


Defaults

No IGMP profiles are defined. When configured, the default action for matching an IGMP profile is to deny matching addresses.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

When you are in IGMP profile configuration mode, you can create the profile by using these commands:

deny: specifies that matching addresses are denied; this is the default condition.

exit: exits from igmp-profile configuration mode.

no: negates a command or resets to its defaults.

permit: specifies that matching addresses are permitted.

range: specifies a range of IP addresses for the profile. This can be a single IP address or a range with a start and an end address.

When entering a range, enter the low IP multicast address, a space, and the high IP multicast address.

You can apply an IGMP profile to one or more Layer 2 interfaces, but each interface can have only one profile applied to it.

Examples

This example shows how to configure IGMP profile 40 that permits the specified range of IP multicast addresses.

Switch(config)# ip igmp profile 40
Switch(config-igmp-profile)# permit
Switch(config-igmp-profile)# range 233.1.1.1 233.255.255.255

You can verify your settings by using the show ip igmp profile privileged EXEC command.

Related Commands

Command
Description

ip igmp filter

Applies the IGMP profile to the specified interface.

show ip igmp profile

Displays the characteristics of all IGMP profiles or the specified IGMP profile number.


ip igmp snooping

Use the ip igmp snooping global configuration command on the switch stack or on a standalone switch to globally enable Internet Group Management Protocol (IGMP) snooping on the switch or to enable it on a VLAN. Use the command with keywords to enable and configure IGMP snooping on a VLAN interface. Use the no form of this command to disable IGMP snooping or to reset the parameters to the default settings.

ip igmp snooping [vlan vlan-id [immediate-leave | mrouter {interface interface-id | learn {cgmp | pim-dvmrp}} | static ip-address interface interface-id]]

no ip igmp snooping [vlan vlan-id [immediate-leave | mrouter {interface interface-id | learn {cgmp | pim-dvmrp}} | static ip-address interface interface-id]]

Syntax Description

vlan vlan-id

(Optional) When used with other keywords, enable IGMP snooping on a VLAN interface. Use the no form of this command to disable IGMP snooping on a VLAN interface. The range is 1 to 4094.

immediate-leave

(Optional) Enable IGMP immediate-leave processing on a VLAN interface. Use the no form of the command to disable the Immediate Leave feature on the interface.

mrouter

(Optional) Add a multicast router port or configure the multicast router learning method. The no form of the command removes the configuration.

interface interface-id

(Optional) With mrouter, specify the next-hop interface to the multicast router.

With static, specify the interface of the member port. It can be one of these values:

fastethernet interface number—a Fast Ethernet 802.3 interface.

gigabitethernet interface number—a Gigabit Ethernet 802.3z interface.

port-channel interface number—a channel interface. The range is 0 to 48.

learn

(Optional) With mrouter, specify the multicast router learning method.

cgmp

Set the switch to learn multicast router ports by snooping on Cisco Group Management Protocol (CGMP) packets.

pim-dvmrp

Set the switch to learn multicast router ports by snooping on IGMP queries and Protocol-Independent Multicast-Distance Vector Multicast Routing Protocol (PIM-DVMRP) packets.

static ip-address

(Optional) Add a Layer 2 port as a member of a multicast group with the specified group IP address.



Note Though visible in the command-line help string, the source-only-learning and tcn keywords are not supported.


Defaults

IGMP snooping is globally enabled on the switch.

IGMP snooping is enabled on VLAN interfaces.

IGMP immediate-leave processing is disabled.

The default learning method is pim-dvmrp—to snoop IGMP queries and PIM-DVMRP packets.

By default, there are no ports specified as members of a static multicast group.

By default, there are no multicast router ports.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

When IGMP snooping is enabled globally, it is enabled in all the existing VLAN interfaces. When IGMP snooping is disabled globally, it is disabled on all the existing VLAN interfaces.

You should only configure the Immediate Leave feature when there is a maximum of one receiver on every port in the VLAN. The configuration is saved in NVRAM.

The Immediate Leave feature is supported only with IGMP Version 2 hosts.

The CGMP learn method is useful for reducing control traffic.

The static keyword is used for configuring the IGMP member ports statically.

The enabled configuration (globally or per VLAN), the learn method, and the static ports and groups are saved in NVRAM.

Examples

This example shows how to globally enable IGMP snooping:

Switch(config)# ip igmp snooping

This example shows how to globally disable IGMP snooping:

Switch(config)# no ip igmp snooping

This example shows how to enable IGMP snooping on VLAN 1:

Switch(config)# ip igmp snooping vlan 1

This example shows how to disable IGMP snooping on VLAN 1:

Switch(config)# no ip igmp snooping vlan 1

This example shows how to enable IGMP immediate-leave processing on VLAN 1:

Switch(config)# ip igmp snooping vlan 1 immediate-leave

This example shows how to disable IGMP immediate-leave processing on VLAN 1:

Switch(config)# no ip igmp snooping vlan 1 immediate-leave

This example shows how to configure a port as a multicast router port:

Switch(config)# ip igmp snooping vlan 1 mrouter interface gigabitethernet1/0/2

This example shows how to specify the multicast router learning method as CGMP:

Switch(config)# no ip igmp snooping vlan 1 mrouter learn cgmp

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

Command
Description

ip igmp snooping report-suppression

Enables IGMP report suppression.

show ip igmp snooping

Displays the snooping configuration.

show ip igmp snooping groups

Displays the IGMP snooping router ports.

show ip igmp snooping groups

Displays IGMP snooping multicast information.


ip igmp snooping querier

Use the ip igmp snooping querier global configuration command to globally enable the Internet Group Management Protocol (IGMP) querier function in Layer 2 networks. Use the command with keywords to enable and configure the IGMP querier feature on a VLAN interface. Use the no form of this command to disable the IGMP querier feature or to reset the parameters to the default settings.

ip igmp snooping querier [address {ip-address} | max-response-time response-time | query-interval | tcn query [count count | interval interval] | timer expiry | version version]

no ip igmp snooping querier [address | max-response-time | query-interval | tcn query count count | interval interval} | timer expiry | version]

Syntax Description

address

(Optional) Specify a source IP address. If you do not specify an IP address, the querier tries to use the global IP address configured for the IGMP querier.

ip-address

Source IP address for the querier.

max-response-time response-time

(Optional) Set the maximum time to wait for an IGMP querier report. You can set a response time from 1 to 25 seconds.

query-interval interval-count

(Optional) Set the interval between IGMP queriers. You can set a count from 1 to 18000 seconds.

tcn query

(Optional) Set the time (in seconds) between Topology Change Notification (TCN) queries.

count count

(Optional) Set the number of TCN queries to be executed during the TCN interval time. You can set a count from 1 to 10.

interval interval

(Optional) Set the TCN query interval time. You can set a time (in seconds) from 1 to 255.

timer expiry

(Optional) Set the length of time until the IGMP querier expires.

version version

(Optional) Select the IGMP version number that the querier feature uses. Select 1 or 2.


Defaults

The IGMP snooping querier feature is globally disabled on the switch.

When enabled, the IGMP snooping querier disables itself if it detects IGMP traffic from a multicast-enabled device.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SEA

This command was introduced.


Usage Guidelines

Use this command to enable IGMP snooping to detect the IGMP version and IP address of a device that sends IGMP query messages, which is also called a querier.

By default, the IGMP snooping querier is configured to detect devices that use IGMP Version 2 (IGMPv2) but does not detect clients that are using IGMP Version 1 (IGMPv1). You can manually configure the max-response-time value when devices use IGMPv2. You cannot configure the max-response-time when devices use IGMPv1. (The value cannot be configured and is set to zero).

Non-RFC compliant devices running IGMPv1 might reject IGMP general query messages that have a non-zero value as the max-response-time value. If you want the devices to accept the IGMP general query messages, configure the IGMP snooping querier to run IGMPv1.

Examples

This example shows how to globally enable the IGMP snooping querier feature:

Switch(config)# ip igmp snooping querier

This example shows how to globally disable the IGMP snooping querier feature:

Switch(config)# no ip igmp snooping querier

This example shows how to set the IGMP snooping querier maximum response time to 25 seconds:

Switch(config)# ip igmp snooping querier max-response-time 25

This example shows how to set the IGMP snooping querier interval time to 60 seconds:

Switch(config)# ip igmp snooping querier query-interval 60

This example shows how to set the IGMP snooping querier TCN query count to 25:

Switch(config)# no ip igmp snooping querier tcn count 25

This example shows how to set the IGMP snooping querier timeout to 60 seconds:

Switch(config)# ip igmp snooping querier timeout expiry 60

This example shows how to set the IGMP snooping querier feature to version 2:

Switch(config)# no ip igmp snooping querier version 2

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

Command
Description

ip igmp snooping report-suppression

Enables IGMP report suppression.

show ip igmp snooping

Displays the IGMP snooping configuration.

show ip igmp snooping groups

Displays the IGMP snooping router ports.

show ip igmp snooping groups

Displays IGMP snooping multicast information.


ip igmp snooping report-suppression

Use the ip igmp snooping report-suppression global configuration command on the switch stack or on a standalone switch to enable Internet Group Management Protocol (IGMP) report suppression. Use the no form of this command to disable IGMP report suppression and forward all IGMP reports to multicast routers.

ip igmp snooping report-suppression

no ip igmp snooping report-suppression

Syntax Description

This command has no arguments or keywords.

Defaults

IGMP report suppression is enabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

IGMP report suppression is supported only when the multicast query has IGMPv1 and IGMPv2 reports. This feature is not supported when the query includes IGMPv3 reports.

The switch uses IGMP report suppression to forward only one IGMP report per multicast router query to multicast devices. When IGMP router suppression is enabled (the default), the switch sends the first IGMP report from all hosts for a group to all the multicast routers. The switch does not send the remaining IGMP reports for the group to the multicast routers. This feature prevents duplicate reports from being sent to the multicast devices.

If the multicast router query includes requests only for IGMPv1 and IGMPv2 reports, the switch forwards only the first IGMPv1 or IGMPv2 report from all hosts for a group to all the multicast routers. If the mulitcast router query also includes requests for IGMPv3 reports, the switch forwards all IGMPv1, IGMPv2, and IGMPv3 reports for a group to the multicast devices.

If you disable IGMP report suppression by entering the no ip igmp snooping report-suppression command, all IGMP reports are forwarded to all the multicast routers.

Examples

This example shows how to disable report suppression:

Switch(config)# no ip igmp snooping report-suppression

This example shows how to enable report suppression:

Switch(config)# ip igmp snooping report-suppression

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

Command
Description

ip igmp snooping

Globally enables IGMP snooping. IGMP snooping must be globally enabled in order to be enabled on a VLAN.

show ip igmp snooping

Displays the IGMP snooping configuration of the switch or the VLAN.


ip source binding

Use the ip source binding global configuration command on the switch stack or on a standalone switch to configure static IP source bindings on the switch. Use the no form of this command to delete static bindings.

ip source binding mac-address vlan vlan-id ip-address interface interface-id

no source binding mac-address vlan vlan-id ip-address interface interface-id

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

mac-address

Specify a MAC address.

vlan vlan-id

Specify a VLAN number. The range is from 1 to 4094.

ip-address

Specify an IP address.

interface interface-id

Specify an interface on which to add or delete an IP source binding.


Defaults

No IP source bindings are configured.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

A static IP source binding entry has an IP address, its associated MAC address, and its associated VLAN number. The entry is based on the MAC address and the VLAN number. If you modify an entry by changing only the IP address, the switch updates the entry instead creating a new one.

Examples

This example shows how to add a static IP source binding:

Switch(config)# ip source binding 0001.1234.1234 vlan 1 172.20.50.5 interface 
gigabitethernet1/0/1 

This example shows how to add a static binding and then modify the IP address for it:

Switch(config)# ip source binding 0001.1357.0007 vlan 1 172.20.50.25 interface 
gigabitethernet1/0/1 
Switch(config)# ip source binding 0001.1357.0007 vlan 1 172.20.50.30 interface 
gigabitethernet1/0/1 

You can verify your settings by entering the show ip source binding privileged EXEC command.

Related Commands

Command
Description

ip verify source

Enables IP source guard on an interface.

show ip source binding

Displays the IP source bindings on the switch.

show ip verify source

Displays the IP source guard configuration on the switch or on a specific interface.


ip ssh

Use the ip ssh global configuration command on the switch stack or on a standalone switch to configure the switch to run Secure Shell (SSH) Version 1 or SSH Version 2. This command is available only when your switch is running the cryptographic (encrypted) software image. Use the no form of this command to return to the default setting.

ip ssh version [1 | 2]

no ip ssh version [1 | 2]

Syntax Description

1

(Optional) Configure the switch to run SSH Version 1 (SSHv1).

2

(Optional) Configure the switch to run SSH Version 2 (SSHv1).


Defaults

The default version is the latest SSH version supported by the SSH client.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

If you do not enter this command or if you do not specify a keyword, the SSH server selects the latest SSH version supported by the SSH client. For example, if the SSH client supports SSHv1 and SSHv2, the SSH server selects SSHv2.

The switch supports an SSHv1 or an SSHv2 server. It also supports an SSHv1 client. For more information about the SSH server and the SSH client, see the software configuration guide for this release.

A Rivest, Shamir, and Adelman (RSA) key pair generated by an SSHv1 server can be used by an SSHv2 server and the reverse.

Examples

This example shows how to configure the switch to run SSH Version 2:

Switch(config)# ip ssh version 2

You can verify your settings by entering the show ip ssh or show ssh privileged EXEC command.

Related Commands

Command
Description

show ip ssh

Displays if the SSH server is enabled and displays the version and configuration information for the SSH server. For syntax information, select Cisco IOS Release 12.2 Configuration Guides and Command References > Cisco IOS Security Command Reference, Release 12.2 > Other Security Features > Secure Shell Commands.

show ssh

Displays the status of the SSH server. For syntax information, select Cisco IOS Release 12.2 Configuration Guides and Command References > Cisco IOS Security Command Reference, Release 12.2 > Other Security Features > Secure Shell Commands.


ip verify source

Use the ip verify source interface configuration command on the switch stack or on a standalone switch to enable IP source guard on an interface. Use the no form of this command to disable IP source guard.

ip verify source [port-security]

no ip verify source

This command is available only if your switch is running the enhanced multilayer image (EMI).

Syntax Description

port-security

(Optional) Enable IP source guard with IP and MAC address filtering.

If you do not enter the port-security keyword, IP source guard with IP address filtering is enabled.


Defaults

IP source guard is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

To enable IP source guard with source IP address filtering, use the ip verify source interface configuration command.

To enable IP source guard with source IP and MAC address filtering, use the ip verify source port-security interface configuration command.

To enable IP source guard with source IP and MAC address filtering, you must enable port security on the interface.

Examples

This example shows how to enable IP source guard with source IP address filtering:

Switch(config-if)# ip verify source 

This example shows how to enable IP source guard with source IP and MAC address filtering:

Switch(config-if)# ip verify source port-security 

You can verify your settings by entering the show ip source binding privileged EXEC command.

Related Commands

Command
Description

ip source binding

Configures static bindings on the switch.

show ip verify source

Displays the IP source guard configuration on the switch or on a specific interface.


l2protocol-tunnel

Use the l2protocol-tunnel interface configuration command on the switch stack or on a standalone switch to enable tunneling of Layer 2 protocols on an access port, 802.1Q tunnel port, or a port channel. You can enable tunneling for Cisco Discovery Protocol (CDP), Spanning Tree Protocol (STP), or VLAN Trunking Protocol (VTP) packets. You can also enable point-to-point tunneling for Port Aggregation Protocol (PAgP), Link Aggregation Control Protocol (LACP), or UniDirectional Link Detection (UDLD) packets. Use the no form of this command to disable tunneling on the interface.

l2protocol-tunnel [cdp | stp | vtp] [point-to-point [pagp | lacp | udld]] | [shutdown-threshold
[cdp | stp | vtp] [point-to-point [pagp | lacp | udld]]] value] | [drop-threshold [cdp | stp | vtp] [point-to-point [pagp | lacp | udld]] value]

no l2protocol-tunnel [cdp | stp | vtp] [point-to-point [pagp | lacp | udld]] | [shutdown-threshold
[cdp | stp | vtp] [point-to-point [pagp | lacp | udld]]] | [drop-threshold [cdp | stp | vtp] [point-to-point [pagp | lacp | udld]]]

Syntax Description

l2protocol-tunnel

Enable point-to-multipoint tunneling of CDP, STP, and VTP packets.

cdp

(Optional) Enable tunneling of CDP, specify a shutdown threshold for CDP, or specify a drop threshold for CDP.

stp

(Optional) Enable tunneling of STP, specify a shutdown threshold for STP, or specify a drop threshold for STP.

vtp

(Optional) Enable tunneling or VTP, specify a shutdown threshold for VTP, or specify a drop threshold for VTP.

point-to-point

(Optional) Enable point-to point tunneling of PAgP, LACP, and UDLD packets.

pagp

(Optional) Enable point-to-point tunneling of PAgP, specify a shutdown threshold for PAgP, or specify a drop threshold for PAgP.

lacp

(Optional) Enable point-to-point tunneling of LACP, specify a shutdown threshold for LACP, or specify a drop threshold for LACP.

udld

(Optional) Enable point-to-point tunneling of UDLD, specify a shutdown threshold for UDLD, or specify a drop threshold for UDLD.

shutdown-threshold

(Optional) Set a shutdown threshold for the maximum rate of Layer 2 protocol packets per second to be received before an interface is shut down.

drop-threshold

(Optional) Set a drop threshold for the maximum rate of Layer 2 protocol packets per second to be received before an interface drops packets.

value

Specify a threshold in packets per second to be received for encapsulation before the interface shuts down, or specify the threshold before the interface drops packets. The range is 1 to 4096. The default is no threshold.


Defaults

The default is that no Layer 2 protocol packets are tunneled.

The default is no shutdown threshold for the number of Layer 2 protocol packets.

The default is no drop threshold for the number of Layer 2 protocol packets.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SE

This command was introduced.


Usage Guidelines

You must enter this command, with or without protocol types, to tunnel Layer 2 packets.

If you enter this command for a port channel, all ports in the channel must have the same configuration.

Layer 2 protocol tunneling across a service-provider network ensures that Layer 2 information is propagated across the network to all customer locations. When protocol tunneling is enabled, protocol packets are encapsulated with a well-known Cisco multicast address for transmission across the network. When the packets reach their destination, the well-known MAC address is replaced by the Layer 2 protocol MAC address.

You can enable Layer 2 protocol tunneling for CDP, STP, and VTP individually or for all three protocols.

In a service-provider network, you can use Layer 2 protocol tunneling to enhance the creation of EtherChannels by emulating a point-to-point network topology. When protocol tunneling is enabled on the service-provider switch for PAgP or LACP, remote customer switches receive the protocol data units (PDUs) and can negotiate automatic creation of EtherChannels.

To enable tunneling of PAgP, LACP, and UDLD packets, you must have a point-to-point network topology. To decrease the link-down detection time, you should also enable UDLD on the interface when you enable tunneling of PAgP or LACP packets.

You can enable point-to-point protocol tunneling for PAgP, LACP, and UDLD individually or for all three protocols.


Caution PAgP, LACP, and UDLD tunneling is only intended to emulate a point-to-point topology. An erroneous configuration that sends tunneled packets to many ports could lead to a network failure.

Enter the shutdown-threshold keyword to control the number of protocol packets per second that are received on an interface before it shuts down. When no protocol option is specified with the keyword, the threshold is applied to each of the tunneled Layer 2 protocol types. If you also set a drop threshold on the interface, the shutdown-threshold value must be greater than or equal to the drop-threshold value.

When the shutdown threshold is reached, the interface is error-disabled. If you enable error recovery by entering the errdisable recovery cause l2ptguard global configuration command, the interface is brought out of the error-disabled state and allowed to retry the operation again when all the causes have timed out. If the error recovery mechanism is not enabled for l2ptguard, the interface stays in the error-disabled state until you enter the shutdown and no shutdown interface configuration commands.

Enter the drop-threshold keyword to control the number of protocol packets per second that are received on an interface before it drops packets. When no protocol option is specified with a keyword, the threshold is applied to each of the tunneled Layer 2 protocol types. If you also set a shutdown threshold on the interface, the drop-threshold value must be less than or equal to the shutdown-threshold value.

When the drop threshold is reached, the interface drops Layer 2 protocol packets until the rate at which they are received is below the drop threshold.

The configuration is saved in NVRAM.


Note For more information about Layer 2 protocol tunneling, see the software configuration guide for this release.


Examples

This example shows how to enable protocol tunneling for CDP packets and to configure the shutdown threshold as 50 packets per second:

Switch(config-if)# l2protocol-tunnel cdp
Switch(config-if)# l2protocol-tunnel shutdown-threshold cdp 50

This example shows how to enable protocol tunneling for STP packets and to configure the drop threshold as 400 packets per second:

Switch(config-if)# l2protocol-tunnel stp
Switch(config-if)# l2protocol-tunnel drop-threshold stp 400

This example shows how to enable point-to-point protocol tunneling for PAgP and UDLD packets and to configure the PAgP drop threshold as 1000 packets per second:

Switch(config-if)# l2protocol-tunnel point-to-point pagp
Switch(config-if)# l2protocol-tunnel point-to-point udld
Switch(config-if)# l2protocol-tunnel drop-threshold point-to-point pagp 1000

Related Commands

Command
Description

l2protocol-tunnel cos

Configures a class of service (CoS) value for all tunneled Layer 2 protocol packets.

show errdisable recovery

Displays errdisable recovery timer information.

show l2protocol-tunnel

Displays information about ports configured for Layer 2 protocol tunneling, including port, protocol, class of service (CoS), and threshold.


l2protocol-tunnel cos

Use the l2protocol-tunnel cos global configuration command on the switch stack or on a standalone switch to configure class of service (CoS) value for all tunneled Layer 2 protocol packets. Use the no form of this command to return to the default setting.

l2protocol-tunnel cos value

no l2protocol-tunnel cos

Syntax Description

value

Specify CoS priority value for tunneled Layer 2 protocol packets. If a CoS value is configured for data packets for the interface, the default is to use this CoS value. If no CoS value is configured for the interface, the default is 5. The range is 0 to 7, with 7 being the highest priority.


Defaults

The default is to use the CoS value configured for data on the interface. If no CoS value is configured, the default is 5 for all tunneled Layer 2 protocol packets.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SE

This command was introduced.


Usage Guidelines

When enabled, the tunneled Layer 2 protocol packets use this CoS value.

The value is saved in NVRAM.

Examples

This example shows how to configure a Layer-2 protocol-tunnel CoS value of 7:

Switch(config)# l2protocol-tunnel cos 7

Related Commands

Command
Description

show l2protocol-tunnel

Displays information about ports configured for Layer 2 protocol tunneling, including CoS.


lacp port-priority

Use the lacp port-priority interface configuration command on the switch stack or on a standalone switch to configure the port priority for the Link Aggregation Control Protocol (LACP). Use the no form of this command to return to the default setting.

lacp port-priority priority

no lacp port-priority

Syntax Description

priority

Port priority for LACP. The range is 1 to 65535.


Defaults

The default is 32768.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced.


Usage Guidelines

This command takes effect only on EtherChannel ports that are already configured for LACP.

The software assigns to every link between systems that operate LACP a unique priority made up of the system priority, system ID, port priority, and the port number. In priority comparisons, numerically lower values have higher priority. The switch uses the priority to decide which ports should be put in standby mode when there is a hardware limitation that prevents all compatible ports from aggregating.

Ports are considered for active use in aggregation in link-priority order starting with the port attached to the highest priority link. Each port is selected for active use if the preceding higher priority selections can also be maintained. Otherwise, the port is selected for standby mode. Use the show etherchannel summary privileged EXEC command to see which ports are in the hot-standby mode (denoted with an H port-state flag).

The lower the priority, the more likely that the port will be used for LACP transmission.

For information about configuring LACP on physical ports, see the "Configuring EtherChannels" chapter in the software configuration guide for this release.

Examples

This example shows how to configure the LACP port priority on a port:

Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# lacp port-priority 1000

You can verify your settings by entering the show lacp [channel-group-number] internal privileged EXEC command.

Related Commands

Command
Description

channel-group

Assigns an Ethernet port to an EtherChannel group.

lacp system-priority

Configures the LACP system priority.

show lacp [channel-group-number] internal

Displays internal information for all channel groups or for the specified channel group.


lacp system-priority

Use the lacp system-priority global configuration command on the switch stack or on a standalone switch to configure the system priority for the Link Aggregation Control Protocol (LACP). Use the no form of this command to return to the default setting.

lacp system-priority priority

no lacp system-priority

Syntax Description

priority

System priority for LACP. The range is 1 to 65535.


Defaults

The default is 32768.

Command Modes

Global configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced.


Usage Guidelines

Although this is a global configuration command, the priority takes effect only on EtherChannels that have physical ports that are already configured for LACP.

The software assigns to every link between systems that operate LACP a unique priority made up of the system priority, system ID, port priority, and the port number. In priority comparisons, numerically lower values have higher priority. The switch uses the priority to decide which ports should be put in standby mode when there is a hardware limitation that prevents all compatible ports from aggregating.

Ports are considered for active use in aggregation in link-priority order, starting with the port attached to the highest priority link. Each port is selected for active use if the preceding higher priority selections can also be maintained. Otherwise, the port is selected for standby mode. Use the show etherchannel summary privileged EXEC command to see which ports are in the hot-standby mode (denoted with an H port-state flag).

The lower the priority, the more likely that the port will be used for LACP transmission.

For more information about configuring LACP on physical ports, see the "Configuring EtherChannels" chapter in the software configuration guide for this release.

Examples

This example shows how to set the LACP system priority:

Switch(config)# lacp system-priority 20000

You can verify your settings by entering the show lacp sys-id privileged EXEC command.

Related Commands

Command
Description

channel-group

Assigns an Ethernet port to an EtherChannel group.

lacp port-priority

Configures the LACP port priority.

show lacp sys-id

Displays the system identifier that is being used by LACP.


logging event power-inline-status

Use the logging event power-inline-status interface configuration command to enable the logging of Power over Ethernet (PoE) events. Use the no form of this command to disable the logging of PoE status events; however, the no form of this command does not disable PoE error events.

logging event power-inline-status

no logging event power-inline-status

Syntax Description

power-inline-status

Enable the logging of PoE messages.


Defaults

Logging of PoE events is enabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

The power-inline-status keyword is available only on PoE interfaces.

Examples

This example shows how to enable logging of PoE events on a port:

Switch(config-if)# interface fastethernet1/0/1
Switch(config-if)# logging event power-inline-status 
Switch(config-if)#

Related Commands

Command
Description

power inline

Configures the power management mode for the specified PoE port or for all PoE ports.

show controllers power inline

Displays the values in the registers of the specified PoE controller.


logging file

Use the logging file global configuration command on the switch stack or on a standalone switch to set logging file parameters. Use the no form of this command to return to the default setting.

logging file filesystem:filename [max-file-size [min-file-size]] [severity-level-number | type]

no logging file filesystem:filename [severity-level-number | type]

Syntax Description

filesystem:filename

Alias for a flash file system. Contains the path and name of the file that contains the log messages.

The syntax for the local flash file system on the stack member or the stack master:
flash:

From the stack master, the syntax for the local flash file system on a stack member:
flash member number

max-file-size

(Optional) Specify the maximum logging file size. The range is 4096 to 2147483647.

min-file-size

(Optional) Specify the minimum logging file size. The range is 1024 to 2147483647.

severity-level-number

(Optional) Specify the logging severity level. The range is 0 to 7. See the type option for the meaning of each level.

type

(Optional) Specify the logging type. These keywords are valid:

emergencies—System is unusable (severity 0).

alerts—Immediate action needed (severity 1).

critical—Critical conditions (severity 2).

errors—Error conditions (severity 3).

warnings—Warning conditions (severity 4).

notifications—Normal but significant messages (severity 5).

information—Information messages (severity 6).

debugging—Debugging messages (severity 7).


Defaults

The minimum file size is 2048 bytes; the maximum file size is 4096 bytes.

The default severity level is 7 (debugging messages and numerically lower levels).

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

The log file is stored in ASCII text format in an internal buffer on a standalone switch, and in the case of a switch stack, on the stack master. If a standalone switch or the stack master fails, the log is lost unless you had previously saved it to flash memory by using the logging file flash:filename global configuration command.

After saving the log to flash memory by using the logging file flash:filename global configuration command, you can use the more flash:filename privileged EXEC command to display its contents.

The command rejects the minimum file size if it is greater than the maximum file size minus 1024; the minimum file size then becomes the maximum file size minus 1024.

Specifying a level causes messages at that level and numerically lower levels to be displayed.

Examples

This example shows how to save informational log messages to a file in flash memory:

Switch(config)# logging file flash:logfile informational

You can verify your setting by entering the show running-config privileged EXEC command.

Related Commands

Command
Description

show running-config

Displays the running configuration on the switch. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference for Release 12.1 > Cisco IOS File Management Commands > Configuration File Commands.


mac access-group

Use the mac access-group interface configuration command on the switch stack or on a standalone switch to apply a MAC access control list (ACL) to a Layer 2 interface. Use the no form of this command to remove all MAC ACLs or the specified MAC ACL from the interface. You create the MAC ACL by using the mac access-list extended global configuration command.

mac access-group {name} in

no mac access-group {name}

Syntax Description

name

Specify a named MAC access list.

in

Specify that the ACL is applied in the ingress direction. Outbound ACLs are not supported on Layer 2 interfaces.


Defaults

No MAC ACL is applied to the interface.

Command Modes

Interface configuration (Layer 2 interfaces only)

Command History

Release
Modification

12.1(14)EA1

This command was introduced.


Usage Guidelines

You can apply MAC ACLs only to ingress Layer 2 interfaces. You cannot apply MAC ACLs to Layer 3 interfaces.

On Layer 2 interfaces, you can filter IP traffic by using IP access lists and non-IP traffic by using MAC access lists. You can filter both IP and non-IP traffic on the same Layer 2 interface by applying both an IP ACL and a MAC ACL to the interface. You can apply no more than one IP access list and one MAC access list to the same Layer 2 interface.

If a MAC ACL is already configured on a Layer 2 interface and you apply a new MAC ACL to the interface, the new ACL replaces the previously configured one.

If you apply an ACL to a Layer 2 interface on a switch, and the switch has an input Layer 3 ACL or a VLAN map applied to a VLAN that the interface is a member of, the ACL applied to the Layer 2 interface takes precedence.

When an inbound packet is received on an interface with a MAC ACL applied, the switch checks the match conditions in the ACL. If the conditions are matched, the switch forwards or drops the packet, according to the ACL.

If the specified ACL does not exist, the switch forwards all packets.


Note For more information about configuring MAC extended ACLs, see the "Configuring Network Security with ACLs" chapter in the software configuration guide for this release.


Examples

This example shows how to apply a MAC extended ACL named macacl2 to an interface:

Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# mac access-group macacl2 in

You can verify your settings by entering the show mac access-group privileged EXEC command. You can see configured ACLs on the switch by entering the show access-lists privileged EXEC command.

Related Commands

Command
Description

show access-lists

Displays the ACLs configured on the switch.

show mac access-group

Displays the MAC ACLs configured on the switch.

show running-config

Displays the running configuration on the switch. For syntax information, select Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


mac access-list extended

Use the mac access-list extended global configuration command on the switch stack or on a standalone switch to create an access list based on MAC addresses for non-IP traffic. Using this command puts you in the extended MAC access list configuration mode. Use the no form of this command to return to the default setting.


Note You cannot apply named MAC extended ACLs to Layer 3 interfaces.


mac access-list extended name

no mac access-list extended name

Syntax Description

name

Assign a name to the MAC extended access list.


Defaults

By default, there are no MAC access lists created.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

MAC named extended lists are used with VLAN maps and class maps.

You can apply named MAC extended ACLs to VLAN maps or to Layer 2 interfaces; you cannot apply named MAC extended ACLs to Layer 3 interfaces.

Entering the mac access-list extended command enables the MAC-access list configuration mode. These configuration commands are available:

default: sets a command to its default.

deny: specifies packets to reject. For more information, see the deny (MAC access-list configuration) MAC-access list configuration command.

exit: exits from MAC-access list configuration mode.

no: negates a command or sets its defaults.

permit: specifies packets to forward. For more information, see the permit (ARP access-list configuration) command.


Note For more information about MAC extended access lists, see the software configuration guide for this release.


Examples

This example shows how to create a MAC named extended access list named mac1 and to enter extended MAC access list configuration mode:

Switch(config)# mac access-list extended mac1
Switch(config-ext-macl)#

This example shows how to delete MAC named extended access list mac1:

Switch(config)# no mac access-list extended mac1

You can verify your settings by entering the show access-lists privileged EXEC command.

Related Commands

Command
Description

deny (MAC access-list configuration)

permit (MAC access-list configuration)

Configures the MAC ACL (in extended MAC-access list configuration mode).

show access-lists

Displays the access lists configured on the switch.

vlan access-map

Defines a VLAN map and enters access-map configuration mode where you can specify a MAC ACL to match and the action to be taken.


mac address-table aging-time

Use the mac address-table aging-time global configuration command on the switch stack or on a standalone switch to set the length of time that a dynamic entry remains in the MAC address table after the entry is used or updated. Use the no form of this command to return to the default setting. The aging time applies to all VLANs or a specified VLAN.

mac address-table aging-time {0 | 10-1000000} [vlan vlan-id]

no mac address-table aging-time {0 | 10-1000000} [vlan vlan-id]


Note Beginning with Cisco IOS Release 12.1(19)EA1, the mac address-table aging-time command replaces the mac-address-table aging-time command (with the hyphen).


Syntax Description

0

This value disables aging. Static address entries are never aged or removed from the table.

10-1000000

Aging time in seconds. The range is 10 to 1000000 seconds.

vlan vlan-id

(Optional) Specify the VLAN ID to which to apply the aging time. The range is 1 to 4094.


Defaults

The default is 300 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(19)EA1

The mac-address-table aging-time command was replaced by the mac address-table aging-time command.


Usage Guidelines

If hosts do not send continuously, increase the aging time to record the dynamic entries for a longer time. Increasing the time can reduce the possibility of flooding when the hosts send again.

If you do not specify a specific VLAN, this command sets the aging time for all VLANs.

Examples

This example shows how to set the aging time to 200 seconds for all VLANs:

Switch(config)# mac address-table aging-time 200

You can verify your setting by entering the show mac address-table aging-time privileged EXEC command.

Related Commands

Command
Description

show mac address-table aging-time

Displays the MAC address table aging time for all VLANs or the specified VLAN.


mac address-table notification

Use the mac address-table notification global configuration command on the switch stack or on a standalone switch to enable the MAC address notification feature on the switch stack. Use the no form of this command to return to the default setting.

mac address-table notification [history-size value] | [interval value]

no mac address-table notification [history-size | interval]


Note Beginning with Cisco IOS Release 12.1(19)EA1, the mac address-table notification command replaces the mac-address-table notification command (with the hyphen).


Syntax Description

history-size value

(Optional) Configure the maximum number of entries in the MAC notification history table. The range is 1 to 500 entries.

interval value

(Optional) Set the notification trap interval. The switch stack sends the notification traps when this amount of time has elapsed. The range is 0 to 2147483647 seconds.


Defaults

By default, the MAC address notification feature is disabled.

The default trap interval value is 1 second.

The default number of entries in the history table is 1.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(19)EA1

The mac-address-table notification command was replaced by the mac address-table notification command.


Usage Guidelines

The MAC address notification feature sends Simple Network Management Protocol (SNMP) traps to the network management system (NMS) whenever a new MAC address is added or an old address is deleted from the forwarding tables. MAC notifications are generated only for dynamic and secure MAC addresses. Events are not generated for self addresses, multicast addresses, or other static addresses.

When you configure the history-size option, the existing MAC address history table is deleted, and a new table is created.

You enable the MAC address notification feature by using the mac address-table notification command. You must also enable MAC address notification traps on an interface by using the snmp trap mac-notification interface configuration command and configure the switch to send MAC address traps to the NMS by using the snmp-server enable traps mac-notification global configuration command.

Examples

This example shows how to enable the MAC address-table notification feature, set the interval time to 60 seconds, and set the history-size to 100 entries:

Switch(config)# mac address-table notification
Switch(config)# mac address-table notification interval 60 
Switch(config)# mac address-table notification history-size 100

You can verify your settings by entering the show mac address-table notification privileged EXEC command.

Related Commands

Command
Description

clear mac address-table notification

Clears the MAC address notification global counters.

show mac address-table notification

Displays the MAC address notification settings on all interfaces or on the specified interface.

snmp-server enable traps

Sends the SNMP MAC notification traps when the mac-notification keyword is appended.

snmp trap mac-notification

Enables the SNMP MAC notification trap on a specific interface.


mac address-table static

Use the mac address-table static global configuration command on the switch stack or on a standalone switch to add static addresses to the MAC address table. Use the no form of this command to remove static entries from the table.

mac address-table static mac-addr vlan vlan-id interface interface-id

no mac address-table static mac-addr vlan vlan-id [interface interface-id]


Note Beginning with Cisco IOS Release 12.1(19)EA1, the mac address-table static command replaces the mac-address-table static command (with the hyphen).


Syntax Description

mac-addr

Destination MAC address (unicast or multicast) to add to the address table. Packets with this destination address received in the specified VLAN are forwarded to the specified interface.

vlan vlan-id

Specify the VLAN for which the packet with the specified MAC address is received. The range is 1 to 4094.

interface interface-id

Interface to which the received packet is forwarded. Valid interfaces include physical ports and port channels.


Defaults

No static addresses are configured.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.1(19)EA1

The mac-address-table static command was replaced by the mac address-table static command.


Examples

This example shows how to add the static address c2f3.220a.12f4 to the MAC address table. When a packet is received in VLAN 4 with this MAC address as its destination, the packet is forwarded to the specified interface:

Switch(config)# mac address-table static c2f3.220a.12f4 vlan 4 interface 
gigabitethernet6/0/1

You can verify your setting by entering the show mac address-table privileged EXEC command.

Related Commands

Command
Description

show mac address-table static

Displays static MAC address table entries only.


mac address-table static drop

Use the mac address-table static drop global configuration command on the switch stack or on a standalone switch to enable unicast MAC address filtering and to configure the switch to drop traffic with a specific source or destination MAC address. Use the no form of this command to return to the default setting.

mac address-table static mac-addr vlan vlan-id drop

no mac address-table static mac-addr vlan vlan-id

Syntax Description

mac-addr

Unicast source or destination MAC address. Packets with this MAC address are dropped.

vlan vlan-id

Specify the VLAN for which the packet with the specified MAC address is received. Valid VLAN IDs are 1 to 4094.


Defaults

Unicast MAC address filtering is disabled. The switch does not drop traffic for specific source or destination MAC addresses.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

Follow these guidelines when using this feature:

Multicast MAC addresses, broadcast MAC addresses, and router MAC addresses are not supported. Packets that are forwarded to the CPU are also not supported.

If you add a unicast MAC address as a static address and configure unicast MAC address filtering, the switch either adds the MAC address as a static address or drops packets with that MAC address, depending on which command was entered last. The second command that you entered overrides the first command.

For example, if you enter the mac address-table static mac-addr vlan vlan-id interface interface-id global configuration command followed by the mac address-table static mac-addr vlan vlan-id drop command, the switch drops packets with the specified MAC address as a source or destination.

If you enter the mac address-table static mac-addr vlan vlan-id drop global configuration command followed by the mac address-table static mac-addr vlan vlan-id interface interface-id command, the switch adds the MAC address as a static address.

Examples

This example shows how to enable unicast MAC address filtering and to configure the switch to drop packets that have a source or destination address of c2f3.220a.12f4. When a packet is received in VLAN 4 with this MAC address as its source or destination, the packet is dropped:

Switch(config)# mac address-table static c2f3.220a.12f4 vlan 4 drop

This example shows how to disable unicast MAC address filtering:

Switch(config)# no mac address-table static c2f3.220a.12f4 vlan 4 

You can verify your setting by entering the show mac address-table static privileged EXEC command.

Related Commands

Command
Description

show mac address-table static

Displays only static MAC address table entries.


macro apply

Use the macro apply interface configuration command on the switch stack or on a standalone switch to apply a macro to an interface or to apply and trace a macro configuration on an interface.

macro {apply | trace} macro-name [parameter {value}] [parameter {value}]
[
parameter {value}]

Syntax Description

apply

Apply a macro to the specified interface.

trace

Use the trace keyword to apply a macro to an interface and to debug the macro.

macro-name

Specify the name of the macro.

parameter value

(Optional) Specify unique parameter values that are specific to the interface. You can enter up to three keyword-value pairs. Parameter keyword matching is case sensitive. All matching occurrences of the keyword are replaced with the corresponding value.


Defaults

This command has no default setting.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.2(18)SE

The parameter value keywords were added.


Usage Guidelines

You can use the macro trace macro-name interface configuration command to apply and show the macros running on an interface or to debug the macro to find any syntax or configuration errors.

If a command fails because of a syntax error or a configuration error when you apply a macro, the macro continues to apply the remaining commands to the interface.

When creating a macro that requires the assignment of unique values, use the parameter value keywords to designate values specific to the interface.

Keyword matching is case sensitive. All matching occurrences of the keyword are replaced with the corresponding value. Any full match of a keyword, even if it is part of a larger string, is considered a match and is replaced by the corresponding value.

Some macros might contain keywords that require a parameter value. You can use the macro apply macro-name ? command to display a list of any required values in the macro. If you apply a macro without entering the keyword values, the commands are invalid and are not applied.

There are Cisco-default Smartports macros embedded in the switch software. You can display these macros and the commands they contain by using the show parser macro user EXEC command.

Follow these guidelines when you apply a Cisco-default Smartports macro on an interface:

Display all macros on the switch by using the show parser macro user EXEC command. Display the contents of a specific macro by using the show parser macro name macro-name user EXEC command.

Keywords that begin with $ mean that a unique parameter value is required. Append the Cisco-default macro with the required values by using the parameter value keywords.

The Cisco-default macros use the $ character to help identify required keywords. There is no restriction on using the $ character to define keywords when you create a macro.

When you apply a macro to an interface, the macro name is automatically added to the interface. You can display the applied commands and macro names by using the show running-configuration interface interface-id user EXEC command.

A macro applied to an interface range behaves the same way as a macro applied to a single interface. When you use an interface range, the macro is applied sequentially to each interface within the range. If a macro command fails on one interface, it is still applied to the remaining interfaces.

You can delete a macro-applied configuration on an interface by entering the default interface interface-id interface configuration command.

Examples

After you have created a macro by using the macro name global configuration command, you can apply it to an interface. This example shows how to apply a user-created macro called duplex to an interface:

Switch(config-if)# macro apply duplex

To debug a macro, use the macro trace interface configuration command to find any syntax or configuration errors in the macro as it is applied to an interface. This example shows how troubleshoot the user-created macro called duplex on an interface:

Switch(config-if)# macro trace duplex
Applying command...`duplex auto'
%Error Unknown error.
Applying command...`speed nonegotiate'

This example shows how to display the Cisco-default cisco-desktop macro and how to apply the macro and set the access VLAN ID to 25 on an interface:

Switch# show parser macro cisco-desktop
--------------------------------------------------------------
Macro name : cisco-desktop
Macro type : default

# Basic interface - Enable data VLAN only
# Recommended value for access vlan (AVID) should not be 1
switchport access vlan $AVID
switchport mode access

# Enable port security limiting port to a single
# MAC address -- that of desktop
switchport port-security
switchport port-security maximum 1

# Ensure port-security age is greater than one minute
# and use inactivity timer
switchport port-security violation restrict
switchport port-security aging time 2
switchport port-security aging type inactivity

# Configure port as an edge network port
spanning-tree portfast
spanning-tree bpduguard enable
--------------------------------------------------------------
Switch#
Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/4
Switch(config-if)# macro apply cisco-desktop $AVID 25

Related Commands

Command
Description

macro description

Adds a description about the macros that are applied to an interface.

macro global

Applies a macro on a switch or applies and traces a macro on a switch.

macro global description

Adds a description about the macros that are applied to the switch.

macro name

Creates a macro.

show parser macro

Displays the macro definition for all macros or for the specified macro.


macro description

Use the macro description interface configuration command on the switch stack or on a standalone switch to enter a description about which macros are applied to an interface. Use the no form of this command to remove the description.

macro description text

no macro description text

Syntax Description

description text

Enter a description about the macros that are applied to the specified interface.


Defaults

This command has no default setting.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

Use the description keyword to associate comment text, or the macro name, with an interface. When multiple macros are applied on a single interface, the description text will be from the last applied macro.

This example shows how to add a description to an interface:

Switch(config-if)# macro description duplex settings

You can verify your settings by entering the show parser macro description privileged EXEC command.

Related Commands

Command
Description

macro apply

Applies a macro on an interface or applies and traces a macro on an interface.

macro global

Applies a macro on a switch or applies and traces a macro on a switch

macro global description

Adds a description about the macros that are applied to the switch.

macro name

Creates a macro.

show parser macro

Displays the macro definition for all macros or for the specified macro.


macro global

Use the macro global global configuration command on the switch stack or on a standalone switch to apply a macro to a switch or to apply and trace a macro configuration on a switch.

macro global {apply | trace} macro-name [parameter {value}] [parameter {value}]
[
parameter {value}]

Syntax Description

apply

Apply a macro to the switch.

trace

Use the trace keyword to apply a macro to a switch and to debug the macro.

macro-name

Specify the name of the macro.

parameter value

(Optional) Specify unique parameter values that are specific to the switch. You can enter up to three keyword-value pairs. Parameter keyword matching is case sensitive. All matching occurrences of the keyword are replaced with the corresponding value.


Defaults

This command has no default setting.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

You can use the macro trace macro-name global configuration command to apply and to show the macros running on a switch or to debug the macro to find any syntax or configuration errors.

If a command fails because of a syntax error or a configuration error when you apply a macro, the macro continues to apply the remaining commands to the switch.

When creating a macro that requires the assignment of unique values, use the parameter value keywords to designate values specific to the switch.

Keyword matching is case sensitive. All matching occurrences of the keyword are replaced with the corresponding value. Any full match of a keyword, even if it is part of a larger string, is considered a match and is replaced by the corresponding value.

Some macros might contain keywords that require a parameter value. You can use the macro global apply macro-name ? command to display a list of any required values in the macro. If you apply a macro without entering the keyword values, the commands are invalid and are not applied.

There are Cisco-default Smartports macros embedded in the switch software. You can display these macros and the commands they contain by using the show parser macro user EXEC command.

Follow these guidelines when you apply a Cisco-default Smartports macro on a switch:

Display all macros on the switch by using the show parser macro user EXEC command. Display the contents of a specific macro by using the show parser macro name macro-name user EXEC command.

Keywords that begin with $ mean that a unique parameter value is required. Append the Cisco-default macro with the required values by using the parameter value keywords.

The Cisco-default macros use the $ character to help identify required keywords. There is no restriction on using the $ character to define keywords when you create a macro.

When you apply a macro to a switch, the macro name is automatically added to the switch. You can display the applied commands and macro names by using the show running-configuration user EXEC command.

You can delete a global macro-applied configuration on a switch only by entering the no version of each command contained in the macro.

Examples

After you have created a new macro by using the macro name global configuration command, you can apply it to a switch. This example shows how see the snmp macro and how to apply the macro and set the hostname to test-server and set the IP precedence value to 7:

Switch# show parser macro name snmp
Macro name : snmp
Macro type : customizable

#enable port security, linkup, and linkdown traps
snmp-server enable traps port-security
snmp-server enable traps linkup
snmp-server enable traps linkdown
#set snmp-server host
snmp-server host ADDRESS
#set SNMP trap notifications precedence
snmp-server ip precedence VALUE

--------------------------------------------------
Switch(config)# macro global apply snmp ADDRESS test-server VALUE 7

To debug a macro, use the macro global trace global configuration command to find any syntax or configuration errors in the macro when it is applied to a switch. In this example, the ADDRESS parameter value was not entered, causing the snmp-server host command to fail while the remainder of the macro is applied to the switch:

Switch(config)# macro global trace snmp VALUE 7
Applying command...`snmp-server enable traps port-security'
Applying command...`snmp-server enable traps linkup'
Applying command...`snmp-server enable traps linkdown'
Applying command...`snmp-server host'
%Error Unknown error.
Applying command...`snmp-server ip precedence 7'

Related Commands

Command
Description

macro apply

Applies a macro on an interface or applies and traces a macro on an interface.

macro description

Adds a description about the macros that are applied to an interface.

macro global description

Adds a description about the macros that are applied to the switch.

macro name

Creates a macro.

show parser macro

Displays the macro definition for all macros or for the specified macro.


macro global description

Use the macro global description global configuration command on the switch stack or on a standalone switch to enter a description about the macros that are applied to the switch. Use the no form of this command to remove the description.

macro global description text

no macro global description text

Syntax Description

description text

Enter a description about the macros that are applied to the switch.


Defaults

This command has no default setting.

Command Modes

Global configuration

Command History

Release
Modification

12.2(20)SE

This command was introduced.


Usage Guidelines

Use the description keyword to associate comment text, or the macro name, with a switch. When multiple macros are applied on a switch, the description text will be from the last applied macro.

This example shows how to add a description to a switch:

Switch(config)# macro global description udld aggressive mode enabled

You can verify your settings by entering the show parser macro description privileged EXEC command.

Related Commands

Command
Description

macro apply

Applies a macro on an interface or applies and traces a macro on an interface.

macro description

Adds a description about the macros that are applied to an interface.

macro global

Applies a macro on a switch or applies and traces a macro on a switch.

macro name

Creates a macro.

show parser macro

Displays the macro definition for all macros or for the specified macro.


macro name

Use the macro name global configuration command on the switch stack or on a standalone switch to create a configuration macro. Use the no form of this command to delete the macro definition.

macro name macro-name

no macro name macro-name

Syntax Description

macro-name

Name of the macro.


Defaults

This command has no default setting.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.2(20)SE

The help string # macro keywords was added.


Usage Guidelines

A macro can contain up to 3000 characters. Enter one macro command per line. Use the @ character to end the macro. Use the # character at the beginning of a line to enter comment text within the macro.

You can define mandatory keywords within a macro by using a help string to specify the keywords. Enter # macro keywords word to define the keywords that are available for use with the macro. You can enter up to three help string keywords separated by a space. If you enter more than three macro keywords, only the first three are shown.

Macro names are case sensitive. For example, the commands macro name Sample-Macro and macro name sample-macro will result in two separate macros.

When creating a macro, do not use the exit or end commands or change the command mode by using interface interface-id. This could cause commands that follow exit, end, or interface interface-id to execute in a different command mode.

The no form of this command only deletes the macro definition. It does not affect the configuration of those interfaces on which the macro is already applied. You can delete a macro-applied configuration on an interface by entering the default interface interface-id interface configuration command. Alternatively, you can create an anti-macro for an existing macro that contains the no form of all the corresponding commands in the original macro. Then apply the anti-macro to the interface.

You can modify a macro by creating a new macro with the same name as the existing macro. The newly created macro overwrites the existing macro but does not affect the configuration of those interfaces on which the original macro was applied.

Examples

This example shows how to create a macro that defines the duplex mode and speed:

Switch(config)# macro name duplex
Enter macro commands one per line. End with the character `@'.
duplex full
speed auto
@

This example shows how create a macro with # macro keywords:

Switch(config)# macro name test
switchport access vlan $VLANID
switchport port-security maximum $MAX
#macro keywords $VLANID $MAX
@

This example shows how to display the mandatory keyword values before you apply the macro to an interface:

switch(config)# interface gi1/0/1
switch(config-if)# macro apply test ?
  WORD  keyword to replace with a value e.g  $VLANID,$MAX
  <cr>

Switch(config-if)# macro apply test $VLANID ?
  WORD  Value of first keyword to replace

Switch(config-if)# macro apply test $VLANID 2 
  WORD  keyword to replace with a value e.g  $VLANID,$MAX
  <cr>

Switch(config-if)# macro apply test $VLANID 2 $MAX ?
  WORD  Value of second keyword to replace

Related Commands

Command
Description

macro apply

Applies a macro on an interface or applies and traces a macro on an interface.

macro description

Adds a description about the macros that are applied to an interface.

macro global

Applies a macro on a switch or applies and traces a macro on a switch

macro global description

Adds a description about the macros that are applied to the switch.

show parser macro

Displays the macro definition for all macros or for the specified macro.


match (access-map configuration)

Use the match access-map configuration command on the switch stack or on a standalone switch to set the VLAN map to match packets against one or more access lists. Use the no form of this command to remove the match parameters.

match {ip address {name | number} [name | number] [name | number]...} | {mac address {name} [name] [name]...}

no match {ip address {name | number} [name | number] [name | number]...} | {mac address {name} [name] [name]...}

Syntax Description

ip address

Set the access map to match packets against an IP address access list.

mac address

Set the access map to match packets against a MAC address access list.

name

Name of the access list to match packets against.

number

Number of the access list to match packets against. This option is not valid for MAC access lists.


Defaults

The default action is to have no match parameters applied to a VLAN map.

Command Modes

Access-map configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You enter access-map configuration mode by using the vlan access-map global configuration command.

You must enter one access list name or number; others are optional. You can match packets against one or more access lists. Matching any of the lists counts as a match of the entry.

In access-map configuration mode, use the match command to define the match conditions for a VLAN map applied to a VLAN. Use the action command to set the action that occurs when the packet matches the conditions.

Packets are matched only against access lists of the same protocol type; IP packets are matched against IP access lists, and all other packets are matched against MAC access lists.

Both IP and MAC addresses can be specified for the same map entry.

Examples

This example shows how to define and apply a VLAN access map vmap4 to VLANs 5 and 6 that will cause the interface to drop an IP packet if the packet matches the conditions defined in access list al2.

Switch(config)# vlan access-map vmap4
Switch(config-access-map)# match ip address al2
Switch(config-access-map)# action drop
Switch(config-access-map)# exit
Switch(config)# vlan filter vmap4 vlan-list 5-6

You can verify your settings by entering the show vlan access-map privileged EXEC command.

Related Commands

Command
Description

access-list

Configures a standard numbered ACL. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.

action

Specifies the action to be taken if the packet matches an entry in an access control list (ACL).

ip access list

Creates a named access list. For syntax information, select Cisco IOS IP Command Reference, Volume 1 of 3:Addressing and Services, Release 12.2 > IP Services Commands.

mac access-list extended

Creates a named MAC address access list.

show vlan access-map

Displays the VLAN access maps created on the switch.

vlan access-map

Creates a VLAN access map.


match (class-map configuration)

Use the match class-map configuration command on the switch stack or on a standalone switch to define the match criteria to classify traffic. Use the no form of this command to remove the match criteria.

match {access-group acl-index-or-name | input-interface interface-id-list | ip dscp dscp-list | ip precedence ip-precedence-list}

no match {access-group acl-index-or-name | input-interface interface-id-list | ip dscp dscp-list | ip precedence ip-precedence-list}

Syntax Description

access-group acl-index-or-name

Number or name of an IP standard or extended access control list (ACL) or MAC ACL. For an IP standard ACL, the ACL index range is 1 to 99 and 1300 to 1999. For an IP extended ACL, the ACL index range is 100 to 199 and 2000 to 2699.

input-interface interface-id-list

Specify the physical ports to which the interface-level class map in a hierarchical policy map applies. You can specify up to six entries in the list by specifying a port (counts as one entry), a list of ports separated by a space (each port counts as an entry), or a range of ports separated by a hyphen (counts as two entries). This keyword is available only in Cisco IOS Release 12.2(25)SE or later.

ip dscp dscp-list

List of up to eight IP Differentiated Services Code Point (DSCP) values to match against incoming packets. Separate each value with a space. The range is 0 to 63. You also can enter a mnemonic name for a commonly-used value.

ip precedence ip-precedence-list

List of up to eight IP-precedence values to match against incoming packets. Separate each value with a space. The range is 0 to 7. You also can enter a mnemonic name for a commonly-used value


Defaults

No match criteria are defined.

Command Modes

Class-map configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.

12.2(25)SE

The input-interface interface-id-list keyword was added.


Usage Guidelines

The match command is used to specify which fields in the incoming packets are examined to classify the packets. Only the IP access group or the MAC access group matching to the Ether Type/Len are supported.

To define packet classification on a physical-port basis, only one match command per class map is supported. In this situation, the match-all and match-any keywords are equivalent.

For the match ip dscp dscp-list or the match ip precedence ip-precedence-list command, you can enter a mnemonic name for a commonly used value. For example, you can enter the match ip dscp af11 command, which is the same as entering the match ip dscp 10 command. You can enter the match ip precedence critical command, which is the same as entering the match ip precedence 5 command. For a list of supported mnemonics, enter the match ip dscp ? or the match ip precedence ? command to see the command-line help strings.

In Cisco IOS Release 12.2(25)SE or later, use the input-interface interface-id-list keyword when you are configuring an interface-level class map in a hierarchical policy map. For the interface-id-list, you can specify up to six entries.

Examples

This example shows how to create a class map called class2, which matches all the incoming traffic with DSCP values of 10, 11, and 12:

Switch(config)# class-map class2
Switch(config-cmap)# match ip dscp 10 11 12
Switch(config-cmap)# exit

This example shows how to create a class map called class3, which matches all the incoming traffic with IP-precedence values of 5, 6, and 7:

Switch(config)# class-map class3
Switch(config-cmap)# match ip precedence 5 6 7 
Switch(config-cmap)# exit

This example shows how to delete the IP-precedence match criteria and to classify traffic using acl1:

Switch(config)# class-map class2
Switch(config-cmap)# match ip precedence 5 6 7 
Switch(config-cmap)# no match ip precedence
Switch(config-cmap)# match access-group acl1
Switch(config-cmap)# exit

This example shows how to specify a list of physical ports to which an interface-level class map in a hierarchical policy map applies:

Switch(config)# class-map match-all class4
Switch(config-cmap)# match input-interface gigabitethernet2/0/1 gigabitethernet2/0/2
Switch(config-cmap)# exit

This example shows how to specify a range of physical ports to which an interface-level class map in a hierarchical policy map applies:

Switch(config)# class-map match-all class4
Switch(config-cmap)# match input-interface gigabitethernet2/0/1 - gigabitethernet2/0/5
Switch(config-cmap)# exit

You can verify your settings by entering the show class-map privileged EXEC command.

Related Commands

Command
Description

class-map

Creates a class map to be used for matching packets to the class whose name you specify.

show class-map

Displays quality of service (QoS) class maps.


mdix auto

Use the mdix auto interface configuration command on the switch stack or on a standalone switch to enable the automatic medium-dependent interface crossover (Auto-MDIX) feature on the interface. When Auto-MDIX is enabled, the interface automatically detects the required cable connection type (straight-through or crossover) and configures the connection appropriately. Use the no form of this command to disable Auto-MDIX.

mdix auto

no mdix auto

Syntax Description

This command has no arguments or keywords.

Defaults

Auto-MDIX is enabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(14)EA1

This command was introduced.

12.2(18)SE

The default setting changed from disabled to enabled.


Usage Guidelines

When you enable Auto-MDIX on an interface, you must also set the speed and duplex on the interface to auto so that the feature operates correctly.

When Auto-MDIX (along with autonegotiation of speed and duplex) is enabled on one or both of connected interfaces, link up occurs, even if the cable type (straight-through or crossover) is incorrect.

Auto-MDIX is supported on all 10/100 and 10/100/1000-Mbps interfaces and on 10/100/1000BASE-T/TX small form-factor pluggable (SFP)-module interfaces. It is not supported on 1000BASE-SX or -LX SFP module interfaces.

In releases earlier than Cisco IOS Release 12.2(18)SE, the default setting is disabled.

Examples

This example shows how to enable Auto-MDIX on a port:

Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# speed auto
Switch(config-if)# duplex auto
Switch(config-if)# mdix auto
Switch(config-if)# end

You can verify the operational state of Auto-MDIX on the interface by entering the show controllers ethernet-controller interface-id phy privileged EXEC command.

Related Commands

Command
Description

show controllers ethernet-controller interface-id phy

Displays general information about internal registers of an interface, including the operational state of Auto-MDIX.


mls qos

Use the mls qos global configuration command on the switch stack or on a standalone switch to enable quality of service (QoS) for the entire switch. When the mls qos command is entered, QoS is enabled with the default parameters on all ports in the system. Use the no form of this command to reset all the QoS-related statistics and to disable the QoS features for the entire switch.

mls qos

no mls qos

Syntax Description

This command has no arguments or keywords.

Defaults

QoS is disabled. There is no concept of trusted or untrusted ports because the packets are not modified (the CoS, DSCP, and IP precedence values in the packet are not changed). Traffic is switched in pass-through mode (packets are switched without any rewrites and classified as best effort without any policing).

When QoS is enabled with the mls qos global configuration command and all other QoS settings are set to their defaults, traffic is classified as best effort (the DSCP and CoS value is set to 0) without any policing. No policy maps are configured. The default port trust state on all ports is untrusted. The default ingress and egress queue settings are in effect.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

QoS must be globally enabled to use QoS classification, policing, mark down or drop, queueing, and traffic shaping features. You can create a policy-map and attach it to a port before entering the mls qos command. However, until you enter the mls qos command, QoS processing is disabled.

Policy-maps and class-maps used to configure QoS are not deleted from the configuration by the no mls qos command, but entries corresponding to policy maps are removed from the switch hardware to save system resources. To re-enable QoS with the previous configurations, use the mls qos command.

Toggling the QoS status of the switch with this command modifies (reallocates) the sizes of the queues. During the queue size modification, the queue is temporarily shut down during the hardware reconfiguration, and the switch drops newly arrived packets for this queue.

Examples

This example shows how to enable QoS on the switch:

Switch(config)# mls qos

You can verify your settings by entering the show mls qos privileged EXEC command.

Related Commands

Command
Description

show mls qos

Displays QoS information.


mls qos aggregate-policer

Use the mls qos aggregate-policer global configuration command on the switch stack or on a standalone switch to define policer parameters, which can be shared by multiple classes within the same policy map. A policer defines a maximum permissible rate of transmission, a maximum burst size for transmissions, and an action to take if either maximum is exceeded. Use the no form of this command to delete an aggregate policer.

mls qos aggregate-policer aggregate-policer-name rate-bps burst-byte exceed-action {drop | policed-dscp-transmit}

no mls qos aggregate-policer aggregate-policer-name

Syntax Description

aggregate-policer-name

Name of the aggregate policer referenced by the police aggregate policy-map class configuration command.

rate-bps

Specify the average traffic rate in bits per second (bps). The range is 8000 to 1000000000.

burst-byte

Specify the normal burst size in bytes. The range is 8000 to 1000000.

exceed-action drop

When the specified rate is exceeded, specify that the switch drop the packet.

exceed-action policed-dscp-transmit

When the specified rate is exceeded, specify that the switch change the Differentiated Services Code Point (DSCP) of the packet to that specified in the policed-DSCP map and then send the packet.


Defaults

No aggregate policers are defined.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

Define an aggregate policer if the policer is shared with multiple classes.

Policers for a port cannot be shared with other policers for another port; traffic from two different ports cannot be aggregated for policing purposes.

The port ASIC device, which controls more than one physical port, supports 256 policers (255 policers plus 1 no policer). The maximum number of policers supported per port is 64. Policers are allocated on demand by the software and are constrained by the hardware and ASIC boundaries. You cannot reserve policers per port (there is no guarantee that a port will be assigned to any policer).

You apply an aggregate policer to multiple classes in the same policy map; you cannot use an aggregate policer across different policy maps.

You cannot delete an aggregate policer if it is being used in a policy map. You must first use the no police aggregate aggregate-policer-name policy-map class configuration command to delete the aggregate policer from all policy maps before using the no mls qos aggregate-policer aggregate-policer-name command.

Policing uses a token-bucket algorithm. You configure the bucket depth (the maximum burst that is tolerated before the bucket overflows) by using the burst-byte option of the police policy-map class configuration command or the mls qos aggregate-policer global configuration command. You configure how fast (the average rate) that the tokens are removed from the bucket by using the rate-bps option of the police policy-map class configuration command or the mls qos aggregate-policer global configuration command. For more information, see the software configuration guide for this release.

Examples

This example shows how to define the aggregate policer parameters and how to apply the policer to multiple classes in a policy map:

Switch(config)# mls qos aggregate-policer agg_policer1 10000 1000000 exceed-action drop
Switch(config)# policy-map policy2
Switch(config-pmap)# class class1
Switch(config-pmap-c)# police aggregate agg_policer1
Switch(config-pmap-c)# exit
Switch(config-pmap)# class class2 
Switch(config-pmap-c)# set dscp 10
Switch(config-pmap-c)# police aggregate agg_policer1
Switch(config-pmap-c)# exit
Switch(config-pmap)# class class3
Switch(config-pmap-c)# trust dscp
Switch(config-pmap-c)# police aggregate agg_policer2
Switch(config-pmap-c)# exit

You can verify your settings by entering the show mls qos aggregate-policer privileged EXEC command.

Related Commands

Command
Description

police aggregate

Creates a policer that is shared by different classes.

show mls qos aggregate-policer

Displays the quality of service (QoS) aggregate policer configuration.


mls qos cos

Use the mls qos cos interface configuration command on the switch stack or on a standalone switch to define the default class of service (CoS) value of a port or to assign the default CoS to all incoming packets on the port. Use the no form of this command to return to the default setting.

mls qos cos {default-cos | override}

no mls qos cos {default-cos | override}

Syntax Description

default-cos

Assign a default CoS value to a port. If packets are untagged, the default CoS value becomes the packet CoS value. The CoS range is 0 to 7.

override

Override the CoS of the incoming packets, and apply the default CoS value on the port to all incoming packets.


Defaults

The default CoS value for a port is 0.

CoS override is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

You can use the default value to assign a CoS and Differentiated Services Code Point (DSCP) value to all incoming packets that are untagged (if the incoming packet does not have a CoS value). You also can assign a default CoS and DSCP value to all incoming packets by using the override keyword.

Use the override keyword when all incoming packets on certain ports deserve higher or lower priority than packets entering from other ports. Even if a port is previously set to trust DSCP, CoS, or IP precedence, this command overrides the previously configured trust state, and all the incoming CoS values are assigned the default CoS value configured with the mls qos cos command. If an incoming packet is tagged, the CoS value of the packet is modified with the default CoS of the port at the ingress port.

Examples

This example shows how to configure the default port CoS to 4 on a port:

Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# mls qos trust cos
Switch(config-if)# mls qos cos 4

This example shows how to assign all the packets entering a port to the default port CoS value of 4 on a port:

Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# mls qos cos 4
Switch(config-if)# mls qos cos override

You can verify your settings by entering the show mls qos interface privileged EXEC command.

Related Commands

Command
Description

show mls qos interface

Displays quality of service (QoS) information.


mls qos dscp-mutation

Use the mls qos dscp-mutation interface configuration command on the switch stack or on a standalone switch to apply a Differentiated Services Code Point (DSCP)-to-DSCP-mutation map to a DSCP-trusted port. Use the no form of this command to return the map to the default settings (no DSCP mutation).

mls qos dscp-mutation dscp-mutation-name

no mls qos dscp-mutation dscp-mutation-name

Syntax Description

dscp-mutation-name

Name of the DSCP-to-DSCP-mutation map. This map was previously defined with the mls qos map dscp-mutation global configuration command.


Defaults

The default DSCP-to-DSCP-mutation map is a null map, which maps incoming DSCPs to the same DSCP values.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

If two quality of service (QoS) domains have different DSCP definitions, use the DSCP-to-DSCP-mutation map to translate one set of DSCP values to match the definition of another domain. You apply the DSCP-to-DSCP-mutation map to the receiving port (ingress mutation) at the boundary of a quality of service (QoS) administrative domain.

With ingress mutation, the new DSCP value overwrites the one in the packet, and QoS handles the packet with this new value. The switch sends the packet out the port with the new DSCP value.

You can configure multiple DSCP-to-DSCP-mutation maps on ingress ports.

You apply the map only to DSCP-trusted ports. If you apply the DSCP mutation map to an untrusted port, to class of service (CoS) or IP-precedence trusted port, the command has no immediate effect until the port becomes DSCP-trusted.

Examples

This example shows how to define the DSCP-to-DSCP-mutation map named dscpmutation1and to apply the map to a port:

Switch(config)# mls qos map dscp-mutation dscpmutation1 10 11 12 13 to 30
Switch(config)# interface gigabitethernet3/0/1
Switch(config-if)# mls qos trust dscp
Switch(config-if)# mls qos dscp-mutation dscpmutation1

This example show how to remove the DSCP-to-DSCP-mutation map name dscpmutation1 from the port and to reset the map to the default:

Switch(config-if)# no mls qos dscp-mutation dscpmutation1

You can verify your settings by entering the show mls qos maps privileged EXEC command.

Related Commands

Command
Description

mls qos map dscp-mutation

Defines the DSCP-to-DSCP-mutation map.

mls qos trust

Configures the port trust state.

show mls qos maps

Displays QoS mapping information.


mls qos map

Use the mls qos map global configuration command on the switch stack or on a standalone switch to define the class of service (CoS)-to-Differentiated Services Code Point (DSCP) map, DSCP-to-CoS map, the DSCP-to-DSCP-mutation map, the IP-precedence-to-DSCP map, and the policed-DSCP map. Use the no form of this command to return to the default map.

mls qos map {cos-dscp dscp1...dscp8 | dscp-cos dscp-list to cos | dscp-mutation dscp-mutation-name in-dscp to out-dscp | ip-prec-dscp dscp1...dscp8 | policed-dscp dscp-list to mark-down-dscp}

no mls qos map {cos-dscp | dscp-cos | dscp-mutation dscp-mutation-name | ip-prec-dscp | policed-dscp}

Syntax Description

cos-dscp dscp1...dscp8

Define the CoS-to-DSCP map.

For dscp1...dscp8, enter eight DSCP values that correspond to CoS values 0 to 7. Separate each DSCP value with a space. The range is 0 to 63.

dscp-cos dscp-list to cos

Define the DSCP-to-CoS map.

For dscp-list, enter up to eight DSCP values, with each value separated by a space. The range is 0 to 63. Then enter the to keyword.

For cos, enter a single CoS value to which the DSCP values correspond. The range is 0 to 7.

dscp-mutation dscp-mutation-name in-dscp to out-dscp

Define the DSCP-to-DSCP-mutation map.

For dscp-mutation-name, enter the mutation map name.

For in-dscp, enter up to eight DSCP values, with each value separated by a space. Then enter the to keyword.

For out-dscp, enter a single DSCP value.

The range is 0 to 63.

ip-prec-dscp dscp1...dscp8

Define the IP-precedence-to-DSCP map.

For dscp1...dscp8, enter eight DSCP values that correspond to the IP precedence values 0 to 7. Separate each DSCP value with a space. The range is 0 to 63.

policed-dscp dscp-list to mark-down-dscp

Define the policed-DSCP map.

For dscp-list, enter up to eight DSCP values, with each value separated by a space. Then enter the to keyword.

For mark-down-dscp, enter the corresponding policed (marked down) DSCP value.

The range is 0 to 63.


Defaults

Table 2-6 shows the default CoS-to-DSCP map:

Table 2-6 Default CoS-to-DSCP Map

CoS Value
DSCP Value

0

0

1

8

2

16

3

24

4

32

5

40

6

48

7

56


Table 2-7 shows the default DSCP-to-CoS map:

Table 2-7 Default DSCP-to-CoS Map 

DSCP Value
CoS Value

0-7

0

8-15

1

16-23

2

24-31

3

32-39

4

40-47

5

48-55

6

56-63

7


Table 2-8 shows the default IP-precedence-to-DSCP map:

Table 2-8 Default IP-Precedence-to-DSCP Map 

IP Precedence Value
DSCP Value

0

0

1

8

2

16

3

24

4

32

5

40

6

48

7

56


The default DSCP-to-DSCP-mutation map is a null map, which maps an incoming DSCP value to the same DSCP value.

The default policed-DSCP map is a null map, which maps an incoming DSCP value to the same DSCP value.

Command Modes

Global configuration

Command History

Release
Modification

12.1(11)AX

This command was introduced.


Usage Guidelines

All the maps are globally defined. All the maps, except the DSCP-to-DSCP-mutation map, are applied to all ports. The DSCP-to-DSCP-mutation map is applied to a specific port.

Examples

This example shows how to define the IP-precedence-to-DSCP map and to map IP-precedence values 0 to 7 to DSCP values of 0, 10, 20, 30, 40, 50, 55, and 60:

Switch# configure terminal
Switch(config)# mls qos map ip-prec-dscp 0 10 20 30 40 50 55 60

This example shows how to define the policed-DSCP map. DSCP values 1, 2, 3, 4, 5, and 6 are marked down to DSCP value 0. Marked DSCP values that not explicitly configured are not modified:

Switch# configure terminal
Switch(config)# mls qos map policed-dscp 1 2 3 4 5 6 to 0

This example shows how to define the DSCP-to-CoS map. DSCP values 20, 21, 22, 23, and 24 are mapped to CoS 1. DSCP values 10, 11, 12, 13, 14, 15, 16, and 17 are mapped to CoS 0:

Switch# configure terminal
Switch(config)# mls qos map dscp-cos 20 21 22 23 24 to 1
Switch(config)# mls qos map dscp-cos 10 11 12 13 14 15 16 17 to 0

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