Catalyst 3560 Switch Command Reference, Rel. 12.2(35)SE
Catalyst 3560 Switch Cisco IOS Commands - aaa accounting through renew ip dhcp
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Catalyst 3560 Switch Cisco IOS Commands

Table Of Contents

Catalyst 3560 Switch Cisco IOS Commands

aaa accounting dot1x

aaa authentication dot1x

aaa authorization network

action

archive download-sw

archive tar

archive upload-sw

arp access-list

auto qos voip

boot auto-download-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 dot1x

clear eap sessions

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 mac address-table move update

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 (IPv6 access-list configuration)

deny (MAC access-list configuration)

diagnostic monitor

diagnostic schedule

diagnostic start

dot1x

dot1x auth-fail max-attempts

dot1x auth-fail vlan

dot1x control-direction

dot1x critical (global configuration)

dot1x critical (interface configuration)

dot1x default

dot1x fallback

dot1x guest-vlan

dot1x host-mode

dot1x initialize

dot1x mac-auth-bypass

dot1x max-reauth-req

dot1x max-req

dot1x multiple-hosts

dot1x pae

dot1x port-control

dot1x re-authenticate

dot1x re-authentication

dot1x reauthentication

dot1x timeout

duplex

errdisable detect cause

errdisable recovery

exception crashinfo

fallback profile

flowcontrol

interface port-channel

interface range

interface vlan

ip access-group

ip address

ip admission

ip admission name proxy http

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 allow-untrusted

ip dhcp snooping information option format remote-id

ip dhcp snooping limit rate

ip dhcp snooping trust

ip dhcp snooping verify

ip dhcp snooping vlan

ip dhcp snooping vlan information option format-type circuit-id string

ip igmp filter

ip igmp max-groups

ip igmp profile

ip igmp snooping

ip igmp snooping last-member-query-interval

ip igmp snooping querier

ip igmp snooping report-suppression

ip igmp snooping tcn

ip igmp snooping tcn flood

ip igmp snooping vlan immediate-leave

ip igmp snooping vlan mrouter

ip igmp snooping vlan static

ip source binding

ip ssh

ip verify source

ipv6 access-list

ipv6 mld snooping

ipv6 mld snooping last-listener-query-count

ipv6 mld snooping last-listener-query-interval

ipv6 mld snooping listener-message-suppression

ipv6 mld snooping robustness-variable

ipv6 mld snooping tcn

ipv6 mld snooping vlan

ipv6 traffic-filter

l2protocol-tunnel

l2protocol-tunnel cos

lacp port-priority

lacp system-priority

link state group

link state track

logging event

logging event power-inline-status

logging file

mac access-group

mac access-list extended

mac address-table aging-time

mac address-table move update

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

media-type

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 (IPv6 access-list configuration)

permit (MAC access-list configuration)

police

police aggregate

policy-map

port-channel load-balance

power inline

power inline consumption

priority-queue

private-vlan

private-vlan mapping

queue-set

radius-server dead-criteria

radius-server host

rcommand

remote-span

renew ip dhcp snooping database


Catalyst 3560 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 IEEE 802.1x sessions. Use the no form of this command to disable IEEE 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.

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

Examples

This example shows how to configure IEEE 802.1x accounting:

Switch(config)# aaa new-model
Switch(config)# aaa accounting dot1x default start-stop group radius

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 IEEE 802.1x.

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.

dot1x reauthentication

Enables or disables periodic reauthentication.

dot1x timeout reauth-period

Sets the number of seconds between re-authentication attempts.


aaa authentication dot1x

Use the aaa authentication dot1x global configuration command to specify the authentication, authorization, and accounting (AAA) method to use on ports complying with the IEEE 802.1x authentication. 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(19)EA1

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 IEEE 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 IEEE 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.


aaa authorization network

Use the aaa authorization network global configuration command to the configure the switch to use user-RADIUS authorization for all network-related service requests, such as IEEE 802.1x per-user access control lists (ACLs) or VLAN assignment. Use the no form of this command to disable RADIUS user authorization.

aaa authorization network default group radius

no aaa authorization network default

Syntax Description

default group radius

Use the list of all RADIUS hosts in the server group as the default authorization list.


Defaults

Authorization is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

Use the aaa authorization network default group radius global configuration command to allow the switch to download IEEE 802.1x authorization parameters from the RADIUS servers in the default authorization list. The authorization parameters are used by features such as per-user ACLs or VLAN assignment to get parameters from the RADIUS servers.

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

Examples

This example shows how to configure the switch for user RADIUS authorization for all network-related service requests:

Switch(config)# aaa authorization network default group radius

You can verify your settings 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 Cisco IOS Configuration Fundamentals Command Reference, Release 12.2 > File Management Commands > Configuration File Management Commands.


action

Use the action access-map configuration command to set the action for the VLAN access map entry. Use the no form of this command to return to the default setting.

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(19)EA1

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 (class-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 download-sw

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

archive download-sw {/allow-feature-upgrade | /directory | /force-reload | /imageonly | /leave-old-sw | /no-set-boot | /overwrite | /reload | /safe} source-url

Syntax Description

/allow-feature-upgrade

Allow installation of an image with a different feature set (for example, upgrade from the IP base image to the IP services image).

/directory

Specify a directory for the images.

/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.

/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:
flash:

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.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.2(20)SE

The http and https keywords were added.

12.2(35)SE

The allow-feature-upgrade and directory keywords were added.


Usage Guidelines

Use the /allow-feature-upgrade option to allow installation of an image with a different feature set, for example, upgrading from the IP base image to the IP services image.

Beginning with Cisco IOS release 12.2(35)SE, you can use the archive download-sw /directory command to specify a directory one time 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 /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. 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.

Use the /directory option to specify a directory for images.

Examples

This example shows how to download a new image from a TFTP server at 172.20.129.10 and to 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 

Related Commands

Command
Description

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 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 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) 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 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 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 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 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

There is no default setting.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(19)EA1

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 c3560-ipservices-tar.12-25.SEB file that is in flash memory. The contents of the tar file appear on the screen:

Switch# archive tar /table flash:c3560-ipservices-12-25.SEB.tar
info (219 bytes)

c3560-ipservices-mz.12-25.SEB/ (directory)
c3560-ipservices-mz.12-25.SEB (610856 bytes)
c3560-ipservices-mz.12-25.SEB/info (219 bytes)
info.ver (219 bytes)

This example shows how to display only the c3560-ipservices-12-25.SEB/html directory and its contents:

Switch# archive tar /table flash:c3560-ipservices-12-25.SEB.tar 
c3560-ipservices-12-25/html
c3560-ipservices-mz.12-25.SEB/html/ (directory)
c3560-ipservices-mz.12-25.SEB/html/const.htm (556 bytes)
c3560-ipservices-mz.12-25.SEB/html/xhome.htm (9373 bytes)
c3560-ipservices-mz.12-25.SEB/html/menu.css (1654 bytes)
<output truncated>

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 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 to upload an existing switch image to a server.

archive upload-sw [/version version_string] destination-url

Syntax Description

/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:
flash:

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 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(19)EA1

This command was introduced.


Usage Guidelines

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 image to a TFTP server at 172.20.140.2:

Switch# archive upload-sw tftp://172.20.140.2/test-image.tar 

Related Commands

Command
Description

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 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 IP services image, formerly known as 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 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.

cisco-softphone

Identify this port as connected to a device running the Cisco SoftPhone, and automatically configure QoS for VoIP.

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(19)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 gigabitethernet0/1
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-download-sw

Use the boot auto-download-sw global configuration command to specify a URL pathname to use for automatic software upgrades. Use the no form of this command to return to the default setting.

boot auto-download-sw source-url

no boot auto-download-sw

Syntax Description

source-url

The source URL alias for automatic upgrades. These options are supported:

The syntax for the local flash file system:
flash:

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

Disabled.

Command Modes

Global configuration

Command History

Release
Modification

Usage Guidelines

This command specifies a path URL to use for automatic software upgrades.

You can use this command to configure the URL for the master switch to access in case of a version-mismatch.

Related Commands

Command
Description

show boot

Displays the settings of the boot environment variables.


boot boothlpr

Use the boot boothlpr global configuration command 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(19)EA1

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 "Catalyst 3560 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 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(19)EA1

This command was introduced.


Usage Guidelines

Filenames and directory names are case sensitive.

This command changes the setting of the CONFIG_FILE environment variable. For more information, see "Catalyst 3560 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 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(19)EA1

This command was introduced.


Usage Guidelines

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 "Catalyst 3560 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 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(19)EA1

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 "Catalyst 3560 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 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(19)EA1

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 "Catalyst 3560 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 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(19)EA1

This command was introduced.


Usage Guidelines

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 "Catalyst 3560 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 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(19)EA1

This command was introduced.


Usage Guidelines

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 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 ...

no boot system

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.


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(19)EA1

This command was introduced.


Usage Guidelines

Filenames and directory names are case sensitive.

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 "Catalyst 3560 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 to assign an Ethernet port to an EtherChannel group, to enable an EtherChannel mode, or both. 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

PAgP modes:
channel-group channel-group-number mode {{auto [non-silent]} | {desirable [non-silent}}

LACP modes:
channel-group channel-group-number mode {active | passive}

On mode:
channel-group channel-group-number mode on

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. An EtherChannel is formed with another port group that is in the desirable or auto mode. When desirable is enabled, silent operation is the default.

non-silent

(Optional) Use in PAgP mode with the auto or desirable keyword when traffic is expected from the other device.

on

Enable on mode.

In on mode, a usable EtherChannel exists only when both connected port groups are 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 received LACP packets 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(19)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

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.

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


Caution You should use care when using the on mode. This is a manual configuration, and ports on both ends of the EtherChannel must have the same configuration. If the group is misconfigured, packet loss or spanning-tree loops can occur.

Do not configure an EtherChannel in both the PAgP and LACP modes. EtherChannel groups running PAgP and LACP can coexist on the same switch. 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 IEEE 802.1x port. If you try to enable IEEE 802.1x authentication on an EtherChannel port, an error message appears, and IEEE 802.1x authentication is not enabled.


Note If IEEE 802.1x authentication is enabled on a not-yet active port of an EtherChannel in software releases earlier than Cisco IOS Release 12.2(20)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. It assigns two static-access ports in VLAN 10 to channel 5 with the PAgP mode desirable:

Switch# configure terminal 
Switch(config)# interface range gigabitethernet0/1 -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. It assigns two static-access ports in VLAN 10 to channel 5 with the LACP mode active:

Switch# configure terminal 
Switch(config)# interface range gigabitethernet0/1 -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 
 
   

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 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(19)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 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(19)EA1

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 gotten 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 to create a class map to be used for matching packets to the class 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(19)EA1

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 dot1x

Use the clear dot1x privileged EXEC command to clear IEEE 802.1x information for the switch or for the specified port.

clear dot1x {all | interface interface-id}

Syntax Description

all

Clear all IEEE 802.1x information for the switch.

interface interface-id

Clear IEEE 802.1x information for the specified interface.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(25)SEE

This command was introduced.


Usage Guidelines

You can clear all the information by using the clear dot1x all command, or you can clear only the information for the specified interface by using the clear dot1x interface interface-id command.

Examples

This example shows how to clear all IEEE 8021.x information:

Switch# clear dot1x all

This example shows how to clear IEEE 8021.x information for the specified interface:

Switch# clear dot1x interface gigabithethernet0/1

You can verify that the information was deleted by entering the show dot1x privileged EXEC command.

Related Commands

Command
Description

show dot1x

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


clear eap sessions

Use the clear eap sessions privileged EXEC command to clear Extensible Authentication Protocol (EAP) session information for the switch or for the specified port.

clear eap sessions [credentials name [interface interface-id] | interface interface-id | method name | transport name] [credentials name | interface interface-id | transport name] ...

Syntax Description

credentials name

Clear EAP credential information for the specified profile.

interface interface-id

Clear EAP information for the specified interface.

method name

Clear EAP information for the specified method.

transport name

Clear EAP transport information for the specified lower level.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(25)SEE

This command was introduced.


Usage Guidelines

You can clear all counters by using the clear eap sessions command, or you can clear only the specific information by using the keywords.

Examples

This example shows how to clear all EAP information:

Switch# clear eap

This example shows how to clear EAP-session credential information for the specified profile:

Switch# clear eap sessions credential type1


You can verify that the information was deleted by entering the show dot1x privileged EXEC command.

Related Commands

Command
Description

show eap

Displays EAP registration and session information for the switch or for the specified port


clear ip arp inspection log

Use the clear ip arp inspection log privileged EXEC command to clear the dynamic Address Resolution Protocol (ARP) inspection log buffer.

clear ip arp inspection log

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 inventory 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 to clear the dynamic Address Resolution Protocol (ARP) inspection statistics.

clear ip arp inspection statistics [vlan vlan-range]

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 inventory 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 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 IP services image, formerly known as 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 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(20)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 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

No default is defined.

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 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(19)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 to delete from the MAC address table a specific dynamic address, all dynamic addresses on a particular interface, 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}

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 4094.

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(19)EA1

This command was introduced.


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 access-group

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 mac address-table move update

Use the clear mac address-table move update privileged EXEC command to clear the mac address-table-move update-related counters.

clear mac address-table move update

Syntax Description

This command has no arguments or keywords.

Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(25)SED

This command was introduced.


Examples

This example shows how to clear the mac address-table move update related counters.

Switch# clear mac address-table move update

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

Related Commands

Command
Description

mac address-table move update {receive | transmit}

Configures MAC address-table move update on the switch.

show mac address-table move update

Displays the MAC address-table move update information on the switch.


clear pagp

Use the clear pagp privileged EXEC command 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(19)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 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 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 | {access | voice}}]]

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

(Optional) Delete the specified secure MAC address from the specified VLAN. Enter one of these options after you enter the vlan keyword:

vlan-id—On a trunk port, specify the VLAN ID of the VLAN on which this address should be cleared.

access—On an access port, clear the specified secure MAC address on the access VLAN.

voice—On an access port, clear the specified secure MAC address on the voice VLAN.

Note The voice keyword is available only if voice VLAN is configured on a port and if that port is not the access VLAN.


Defaults

No default is defined.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(25)SEA

This command was introduced.

12.2(25)SEB

The access and voice keywords were added.


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 gigabitethernet0/1

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 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(19)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 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(19)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 IEEE 802.1D switches. If a rapid-PVST+ switch or an MSTP switch receives a legacy IEEE 802.1D configuration bridge protocol data unit (BPDU) with the protocol version set to 0, it sends only IEEE 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 IEEE 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 gigabitethernet0/1

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 changes to the forwarding state.


clear vmps statistics

Use the clear vmps statistics privileged EXEC command 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(19)EA1

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 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(19)EA1

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 commandfrom 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(19)EA1

This command was introduced.


Usage Guidelines

This command is available only on 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

debug 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 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(19)EA1

This command was introduced.


Usage Guidelines

This command is available only on the 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 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(19)EA1

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 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(19)EA1

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(19)EA1

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 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(19)EA1

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(19)EA1

This command was introduced.


Usage Guidelines

When you enter the no cluster run command on a cluster command switch, 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(19)EA1

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 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(19)EA1

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 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(19)EA1

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 0/1 - 2 is a valid range; gigabitethernet 0/1-2 is not a valid range

Valid values for type and interface:

vlan vlan-id - vlan-ID, where the VLAN ID is 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 module/{first port} - {last port}

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

For physical interfaces:

module is always 0.

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

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

gigabitethernet0/1 - 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:

fastethernet0/3, gigabitethernet0/1 - 2

fastethernet0/3 -4, gigabitethernet0/1 - 2

Examples

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

Switch(config)# define interface-range macro1 fastethernet0/1 - 2, gigabitethernet0/1 - 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 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:
flash:

/file-url

The path (directory) and filename to delete.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(19)EA1

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 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 IP services image, formerly known as 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 (IPv6 access-list configuration)

Use the deny command in IPv6 access list configuration mode to set deny conditions for an IPv6 access list. Use the no form of this command to remove the deny conditions.

deny {protocol} {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator [port-number]] [dscp value] [fragments] [log] [log-input] [sequence value] [time-range name]

no deny {protocol} {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator [port-number]] [dscp value] [fragments] [log] [log-input] [sequence value] [time-range name]

Internet Control Message Protocol

deny icmp {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator [port-number]] [icmp-type [icmp-code] | icmp-message] [dscp value] [log] [log-input] [sequence value] [time-range name]

Transmission Control Protocol

deny tcp {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator [port-number]] [ack] [dscp value] [established] [fin] [log] [log-input] [neq {port | protocol}] [psh] [range {port | protocol}] [rst] [sequence value] [syn] [time-range name] [urg]

User Datagram Protocol

deny udp {source-ipv6-prefix/prefix-length | any | host source-ipv6-address} [operator [port-number]] {destination-ipv6-prefix/prefix-length | any | host destination-ipv6-address} [operator [port-number]] [dscp value] [log] [log-input] [neq {port | protocol}] [range {port | protocol}] [sequence value] [time-range name]


Note This command is available only if the switch is running the advanced IP services image and you have configured a dual IPv4 and IPv6 Switch Database Management (SDM) template on the switch.


Syntax Description

protocol

Name or number of an Internet protocol. It can be one of the keywords ahp, esp, icmp, ipv6, pcp, sctp, tcp, or udp, or an integer in the range from 0 to 255 representing an IPv6 protocol number.

source-ipv6-prefix/prefix-length

The source IPv6 network or class of networks about which to set deny conditions.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

Note Although the CLI help shows a prefix-length range of /0 to /128, the switch supports IPv6 address-matching only for prefixes in the range of /0 to /64 and extended universal identifier (EUI)-based /128 prefixes for aggregatable global unicast and link-local host addresses.

any

An abbreviation for the IPv6 prefix ::/0.

host source-ipv6-address

The source IPv6 host address for which to set deny conditions.

This source-ipv6-address argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

operator [port-number]

(Optional) Specify an operator that compares the source or destination ports of the specified protocol. Operators are lt (less than), gt (greater than), eq (equal), neq (not equal), and range (inclusive range).

If the operator is positioned after the source-ipv6-prefix/prefix-length argument, it must match the source port.

If the operator is positioned after the destination-ipv6-prefix/prefix-length argument, it must match the destination port.

The range operator requires two port numbers. All other operators require one port number.

The optional port-number argument is a decimal number or the name of a TCP or a UDP port. A port number is a number from 0 to 65535. TCP port names can be used only when filtering TCP. UDP port names can be used only when filtering UDP.

destination-ipv6-prefix/
prefix-length

The destination IPv6 network or class of networks for which to set deny conditions.

This argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

Note Although the CLI help shows a prefix-length range of /0 to /128, the switch supports IPv6 address-matching only for prefixes in the range of /0 to /64 and EUI-based /128 prefixes for aggregatable global unicast and link-local host addresses.

host destination-ipv6-address

The destination IPv6 host address for which to set deny conditions.

This destination-ipv6-address argument must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons.

dscp value

(Optional) Match a differentiated services code point value against the traffic class value in the Traffic Class field of each IPv6 packet header. The acceptable range is from 0 to 63.

fragments

(Optional) Match non-initial fragmented packets where the fragment extension header contains a non-zero fragment offset. The fragments keyword is an option only if the protocol is ipv6 and the operator [port-number] arguments are not specified.

log

(Optional) Send an informational logging message to the console about the packet that matches the entry. (The level of messages sent to the console is controlled by the logging console command.)

The message includes the access list name and sequence number, whether the packet was denied; the protocol, whether it was TCP, UDP, ICMP, or a number; and, if appropriate, the source and destination addresses and source and destination port numbers. The message is generated for the first packet that matches, and then at 5-minute intervals, including the number of packets denied in the prior 5-minute interval.

Note Logging is not supported for port ACLs.

log-input

(Optional) Provide the same function as the log keyword, except that the logging message also includes the receiving interface.

sequence value

(Optional) Specify the sequence number for the access list statement. The acceptable range is from 1 to 4294967295.

time-range name

(Optional) Specify the time range that applies to the deny statement. The name of the time range and its restrictions are specified by the time-range and absolute or periodic commands, respectively.

icmp-type

(Optional) Specify an ICMP message type for filtering ICMP packets. ICMP packets can be filtered by an ICMP message type. The type is a number from 0 to 255.

icmp-code

(Optional) Specify an ICMP message code for filtering ICMP packets. ICMP packets that are filtered by ICMP message type can also be filtered by the ICMP message code. The code is a number from 0 to 255.

icmp-message

(Optional) Specify an ICMP message name for filtering ICMP packets. ICMP packets can be filtered by an ICMP message name or an ICMP message type and code. The possible names are listed in the "Usage Guidelines" section.

ack

(Optional) Only for the TCP protocol: Acknowledgment (ACK) bit set.

established

(Optional) Only for the TCP protocol: Means the connection has been established. A match occurs if the TCP datagram has the ACK or RST bits set. The nonmatching case is that of the initial TCP datagram to form a connection.

fin

(Optional) Only for the TCP protocol: Fin bit set; no more data from sender.

neq {port | protocol}

(Optional) Match only packets that are not on a given port number.

psh

(Optional) Only for the TCP protocol: Push function bit set.

range {port | protocol}

(Optional) Match only packets in the range of port numbers.

rst

(Optional) Only for the TCP protocol: Reset bit set.

syn

(Optional) Only for the TCP protocol: Synchronize bit set.

urg

(Optional) Only for the TCP protocol: Urgent pointer bit set.



Note Although visible in the command-line help strings, the flow-label, routing, and undetermined-transport keywords are not supported.


Defaults

No IPv6 access list is defined.

Command Modes

IPv6 access list configuration

Command History

Release
Modification

12.2(25)SED

This command was introduced.


Usage Guidelines

The deny (IPv6 access-list configuration mode) command is similar to the deny (IPv4 access-list configuration mode) command, except that it is IPv6-specific.

Use the deny (IPv6) command after the ipv6 access-list command to enter IPv6 access list configuration mode and to define the conditions under which a packet passes the access list.

Specifying IPv6 for the protocol argument matches against the IPv6 header of the packet.

By default, the first statement in an access list is number 10, and the subsequent statements are numbered in increments of 10.

You can add permit, deny, or remark statements to an existing access list without re-entering the entire list. To add a new statement anywhere other than at the end of the list, create a new statement with an appropriate entry number that falls between two existing entry numbers to show where it belongs.


Note Every IPv6 ACL has implicit permit icmp any any nd-na, permit icmp any any nd-ns, and deny ipv6 any any statements as its last match conditions. The two permit conditions allow ICMPv6 neighbor discovery. To disallow ICMPv6 neighbor discovery and to deny icmp any any nd-na or icmp any any nd-ns, there must be an explicit deny entry in the ACL. For the implicit deny ipv6 any any statement to take effect, an IPv6 ACL must contain at least one entry.

The IPv6 neighbor discovery process uses the IPv6 network layer service. Therefore, by default, IPv6 ACLs implicitly allow IPv6 neighbor discovery packets to be sent and received on an interface. In IPv4, the Address Resolution Protocol (ARP), which is equivalent to the IPv6 neighbor discovery process, uses a separate data-link layer protocol. Therefore, by default, IPv4 ACLs implicitly allow ARP packets to be sent and received on an interface.


Both the source-ipv6-prefix/prefix-length and destination-ipv6-prefix/prefix-length arguments are used for traffic filtering. (The source prefix filters traffic based upon the traffic source; the destination prefix filters traffic based upon the traffic destination.)

The switch supports only prefixes from /0 to /64 and EUI-based /128 prefixes for aggregatable global unicast and link-local host addresses.

The fragments keyword is an option only if the protocol is ipv6 and the operator [port-number] arguments are not specified.

This is a list of ICMP message names:

beyond-scope

destination-unreachable

echo-reply

echo-request

header

hop-limit

mld-query

mld-reduction

mld-report

nd-na

nd-ns

next-header

no-admin

no-route

packet-too-big

parameter-option

parameter-problem

port-unreachable

reassembly-timeout

renum-command

renum-result

renum-seq-number

router-advertisement

router-renumbering

router-solicitation

time-exceeded

unreachable

 

Examples

This example configures the IPv6 access list named CISCO and applies the access list to outbound traffic on a Layer 3 interface. The first deny entry in the list prevents all packets that have a destination TCP port number greater than 5000 from leaving the interface. The second deny entry in the list prevents all packets that have a source UDP port number less than 5000 from leaving the interface. The second deny also logs all matches to the console. The first permit entry in the list permits all ICMP packets to leave the interface. The second permit entry in the list permits all other traffic to leave the interface. The second permit entry is necessary because an implicit deny-all condition is at the end of each IPv6 access list.

Switch(config)# ipv6 access-list CISCO
Switch(config-ipv6-acl)# deny tcp any any gt 5000
Switch config-ipv6-acl)# deny ::/0 lt 5000 ::/0 log
Switch(config-ipv6-acl)# permit icmp any any
Switch(config-ipv6-acl)# permit any any
Switch(config-ipv6-acl)# exit
Switch(config)# interface gigabitethernet0/3
Switch(config-if)# no switchport
Switch(config-if)# ipv6 address 2001::/64 eui-64
Switch(config-if)# ipv6 traffic-filter CISCO out

Related Commands

Command
Description

ipv6 access-list

Defines an IPv6 access list and enters IPv6 access list configuration mode.

ipv6 traffic-filter

Filters incoming or outgoing IPv6 traffic on an interface.

permit (IPv6 access-list configuration)

Sets permit conditions for an IPv6 access list.

show ipv6 access-list

Displays the contents of all current IPv6 access lists.


deny (MAC access-list configuration)

Use the deny MAC access-list configuration command 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(19)EA1

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.

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.


diagnostic monitor

Use the diagnostic monitor global configuration command to configure the health-monitoring diagnostic testing. Use the no form of this command to disable testing and return to the default settings.

diagnostic monitor test {test-id | test-id-range | all}

diagnostic monitor interval test {test-id | test-id-range | all} hh:mm:ss milliseconds day

diagnostic monitor syslog

diagnostic monitor threshold test {test-id | test-id-range | all} count failure count

no diagnostic monitor test {test-id | test-id-range | all}

no diagnostic monitor interval test {test-id | test-id-range | all}

no diagnostic monitor syslog

no diagnostic monitor threshold test {test-id | test-id-range | all} failure count

Syntax Description

test

Specify a test to run.

test-id

Identification number for the test to be run; see the "Usage Guidelines" section for additional information.

test-id-range

Range of identification numbers for tests to be run; see the "Usage Guidelines" section for additional information.

all

Run all the diagnostic tests.

interval

Specify an interval between tests to be run.

hh:mm:ss

Specify the number of time between tests; see the "Usage Guidelines" section for formatting guidelines.

milliseconds

Specify the time in milliseconds; valid values are 0 to 999.

day

Specify the number of days between tests; see the "Usage Guidelines" section for formatting guidelines.

syslog

Enable the generation of a syslog message when a health-monitoring test fails.

threshold

Specify the failure threshold.

failure count count

Specify the failure threshold count.


Defaults

The defaults are as follows:

Monitoring is disabled.

syslog is enabled.

Command Modes

Global configuration

Command History

Release
Modification

12.2(35)SE

This command was introduced.


Usage Guidelines

Use these guidelines when scheduling testing:

test-idEnter the show diagnostic content privileged EXEC command to display the test ID list.

test-id-rangeEnter the show diagnostic content command to display the test ID list. Enter the range as integers separated by a comma and a hyphen (for example, 1,3-6 specifies test IDs 1, 3, 4, 5, and 6).

hh—Enter the hours from 0 to 23.

mm—Enter the minutes from 0 to 60.

ss—Enter the seconds from 0 to 60.

milliseconds—Enter the milliseconds from 0 to 999.

day—Enter the day as a number from 0 to 20.

When entering the diagnostic monitor test {test-id | test-id-range | all} command, follow these required guidelines

Isolate network traffic by disabling all connected ports, and do not pump test packets during the test.

Reset the system or the test module before putting the system back into the normal operating mode.

Examples

This example shows how to configure the specified test to run every 2 minutes:

Switch(config)# diagnostic monitor interval test 1 00:02:00 0 1

This example shows how to enable the generation of a syslog message when any health monitoring test fails:

Switch(config)# diagnostic monitor syslog

Related Commands

Command
Description

show diagnostic

Displays online diagnostic test results.


diagnostic schedule

Use the diagnostic schedule privileged EXEC command to configure the scheduling of diagnostic testing. Use the no form of this command to remove the scheduling and return to the default setting.

diagnostic schedule test {test-id | test-id-range | all | basic | non-disruptive} {daily hh:mm | on mm dd yyyy hh:mm | weekly day-of-week hh:mm}

no diagnostic schedule test {test-id | test-id-range | all | basic | non-disruptive} {daily hh:mm | on mm dd yyyy hh:mm | weekly day-of-week hh:mm}

Syntax Description

test

Specify the test to be scheduled.

test-id

Identification number for the test to be run; see the "Usage Guidelines" section for additional information.

test-id-range

Range of identification numbers for tests to be run; see the "Usage Guidelines" section for additional information.

all

Run all diagnostic tests.

basic

Run basic on-demand diagnostic tests.

non-disruptive

Run the nondisruptive health-monitoring tests.

daily hh:mm

Specify the daily scheduling of a test-based diagnostic task; see the "Usage Guidelines" section for formatting guidelines.

on mm dd yyyy hh:mm

Specify the scheduling of a test-based diagnostic task; see the "Usage Guidelines" section for formatting guidelines.

weekly day-of-week hh:mm

Specify the weekly scheduling of a test-based diagnostic task; see the "Usage Guidelines" section for formatting guidelines.


Defaults

This command has no default settings.

Command Modes

Global configuration

Command History

Release
Modification

12.2(35)SE

This command was introduced.


Usage Guidelines

Use these guidelines when scheduling testing:

test-idEnter the show diagnostic content command to display the test ID list.

test-id-rangeEnter the show diagnostic content command to display the test ID list. Enter the range as integers separated by a comma and a hyphen (for example, 1,3-6 specifies test IDs 1, 3, 4, 5, and 6).

hh:mm—Enter the time as a 2-digit number (for a 24-hour clock) for hours:minutes; the colon (:) is required.

mm—Spell out the month, such as January, February... December (either upper case or lower case characters).

dd—Enter the day as a 2-digit number.

yyyy—Enter the year as a 4-digit number.

day-of-week—Spell out the day of the week, such as Monday, Tuesday... Sunday (either upper case or lower case characters).

Examples

This example shows how to schedule diagnostic testing on a specific date and time :

Switch(config)# diagnostic schedule test 1,2,4-6 on january 3 2006 23:32

This example shows how to schedule diagnostic testing to occur weekly at a certain time:

Switch(config)# diagnostic schedule test 1,2,4-6 weekly friday 09:23

Related Commands

Command
Description

show diagnostic

Displays online diagnostic test results.


diagnostic start

Use the diagnostic start user command to run the specified diagnostic test.

diagnostic start test {test-id | test-id-range | all | basic | non-disruptive}

Syntax Description

test

Specify a test to run.

test-id

Identification number for the test to be run; see the "Usage Guidelines" section for additional information.

test-id-range

Range of identification numbers for tests to be run; see the "Usage Guidelines" section for additional information.

all

Run all diagnostic tests.

basic

Run basic on-demand diagnostic tests.

non-disruptive

Run the nondisruptive health-monitoring tests.


Defaults

This command has no default settings.

Command Modes

User EXEC

Command History

Release
Modification

12.2(35)SE

This command was introduced.


Usage Guidelines

Enter the show diagnostic content command to display the test ID list.

Enter the test-id-range as integers separated by a comma and a hyphen (for example, 1,3-6 specifies test IDs 1, 3, 4, 5, and 6).

Examples

This example shows how to start all the diagnostic test on a switch:

Switch#diagn start test all
Diagnostic[]: Running test(s) 2-6 will cause the switch under test to reload after 
completion of the test list.
Diagnostic[]: Running test(s) 2-6 may disrupt normal system operation
Do you want to continue? [no]: 
Switch#

Related Commands

Command
Description

show diagnostic

Displays online diagnostic test results.


dot1x

Use the dot1x global configuration command to globally enable IEEE 802.1x authentication. Use the no form of this command to return to the default setting.

dot1x {critical {eapol | recovery delay milliseconds} | system-auth-control}

no dot1x {credentials | critical {eapol | recovery delay} | system-auth-control}


Note Though visible in the command-line help strings, the credentials name keywords are not supported.


Syntax Description

critical {eapol | recovery delay milliseconds}

Configure the inaccessible authentication bypass parameters. For more information, see the dot1x critical (global configuration) command.

system-auth-control

Enable IEEE 802.1x authentication globally on the switch.


Defaults

IEEE 802.1x authentication is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.2(25)SE

The guest-vlan supplicant keywords were added.

12.2(25)SEE

The critical {eapol | recovery delay milliseconds} keywords were added. The guest-vlan supplicant keyword was removed.


Usage Guidelines

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

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

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

Examples

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

Switch(config)# dot1x system-auth-control

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

Related Commands

Command
Description

dot1x critical (global configuration)

Configures the parameters for the inaccessible authentication bypass feature on the switch.

dot1x guest-vlan

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

dot1x port-control

Enables manual control of the authorization state of the port.

show dot1x [interface interface-id]

Displays IEEE 802.1x status for the specified port.


dot1x auth-fail max-attempts

Use the dot1x auth-fail max-attempts interface configuration command to configure the maximum allowable authentication attempts before a port is moved to the restricted VLAN. To return to the default setting, use the no form of this command.

dot1x auth-fail max-attempts max-attempts

no dot1x auth-fail max-attempts

Syntax Description

max-attempts

Specify a maximum number of authentication attempts allowed before a port is moved to the restricted VLAN. The range is 1 to 3, the default value is 3.


Defaults

The default value is 3 attempts.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SED

This command was introduced.


Usage Guidelines

If you reconfigure the maximum number of authentication attempts allowed by the VLAN, the change takes effect after the re-authentication timer expires.

Examples

This example shows how to set 2 as the maximum number of authentication attempts allowed before the port is moved to the restricted VLAN on port 3:

Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface gigabitethernet0/3
Switch(config-if)# dot1x auth-fail max-attempts 2
Switch(config-if)# end
Switch(config)# end
Switch#

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

Related Commands

Command
Description

dot1x auth-fail vlan [vlan id]

Enables the optional restricted VLAN feature.

dot1x max-reauth-req [count]

Sets the maximum number of times that the switch restarts the authentication process before a port changes to the unauthorized state.

show dot1x [interface interface-id]

Displays IEEE 802.1x status for the specified port.


dot1x auth-fail vlan

Use the dot1x auth-fail vlan interface configuration command to enable the restricted VLAN on a port. To return to the default setting, use the no form of this command.

dot1x auth-fail vlan vlan-id

no dot1x auth-fail vlan

Syntax Description

vlan-id

Specify a VLAN in the range of 1 to 4094.


Defaults

No restricted VLAN is configured.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SED

This command was introduced.


Usage Guidelines

You can configure a restricted VLAN on ports configured as follows:

single-host (default) mode

auto mode for authorization

You should enable re-authentication. The ports in restricted VLANs do not receive re-authentication requests if it is disabled. To start the re-authentication process, the restricted VLAN must receive a link-down event or an Extensible Authentication Protocol (EAP) logoff event from the port. If a host is connected through a hub, the port might never receive a link-down event when that host is disconnected, and, as a result, might not detect any new hosts until the next re-authentication attempt occurs.

If the supplicant fails authentication, the port is moved to a restricted VLAN, and an EAP success message is sent to the supplicant. Because the supplicant is not notified of the actual authentication failure, there might be confusion about this restricted network access. An EAP success message is sent for these reasons:

If the EAP success message is not sent, the supplicant tries to authenticate every 60 seconds (the default) by sending an EAP-start message.

Some hosts (for example, devices running Windows XP) cannot implement DHCP until they receive an EAP success message.

A supplicant might cache an incorrect username and password combination after receiving an EAP success message from the authenticator and re-use that information in every re-authentication. Until the supplicant sends the correct username and password combination, the port remains in the restricted VLAN.

Internal VLANs used for Layer 3 ports cannot be configured as restricted VLANs.

You cannot configure a VLAN to be both a restricted VLAN and a voice VLAN. If you do this, a syslog message is generated.

When a restricted VLAN port is moved to an unauthorized state, the authentication process restarts. If the supplicant fails the authentication process again, the authenticator waits in the held state. After the supplicant has correctly re-authenticated, all IEEE 802.1x ports are reinitialized and treated as normal IEEE 802.1x ports.

When you reconfigure a restricted VLAN as a different VLAN, any ports in the restricted VLAN are also moved, and the ports stay in their currently authorized state.

When you shut down or remove a restricted VLAN from the VLAN database, any ports in the restricted VLAN are immediately moved to an unauthorized state, and the authentication process restarts. The authenticator does not wait in a held state because the restricted VLAN configuration still exists. While the restricted VLAN is inactive, all authentication attempts are counted so that when the restricted VLAN becomes active, the port is immediately placed in the restricted VLAN.

The restricted VLAN is supported only in single host mode (the default port mode). For this reason, when a port is placed in a restricted VLAN, the supplicant's MAC address is added to the MAC address table, and any other MAC address that appears on the port is treated as a security violation.

Examples

This example shows how to configure a restricted VLAN on port 1:

Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# dot1x auth-fail vlan 40
Switch(config-if)# end
Switch#

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

Related Commands

Command
Description

dot1x auth-fail max-attempts [max-attempts]

Configures the number of authentication attempts allowed before assigning a supplicant to the restricted VLAN.

show dot1x [interface interface-id]

Displays IEEE 802.1x status for the specified port.


dot1x control-direction

Use the dot1x control-direction interface configuration command to enable the IEEE 802.1x authentication with the wake-on-LAN (WoL) feature and to configure the port control as unidirectional or bidirectional. Use the no form of this command to return to the default setting.

dot1x control-direction {both | in}

no dot1x control-direction

Syntax Description

both

Enable bidirectional control on port. The port cannot receive packets from or send packets to the host.

in

Enable unidirectional control on port. The port can send packets to the host but cannot receive packets from the host.


Defaults

The port is in bidirectional mode.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SEC

This command was introduced.


Usage Guidelines

Use the both keyword or the no form of this command to return to the default setting, bidirectional mode.

For more information about WoL, see the "Using IEEE 802.1x Authentication with Wake-on-LAN" section in the "Configuring IEEE 802.1x Port-Based Authentication" chapter in the software configuration guide.

Examples

This example shows how to enable unidirectional control:

Switch(config-if)# dot1x control-direction in

This example shows how to enable bidirectional control:

Switch(config-if)# dot1x control-direction both

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

The show dot1x all privileged EXEC command output is the same for all switches except for the port names and the state of the port. If a host is attached to the port but is not yet authenticated, a display similar to this appears:

Supplicant MAC 0002.b39a.9275
AuthSM State = CONNECTING
BendSM State = IDLE
PortStatus = UNAUTHORIZED

If you enter the dot1x control-direction in interface configuration command to enable unidirectional control, this appears in the show dot1x all command output:

ControlDirection  = In

If you enter the dot1x control-direction in interface configuration command and the port cannot support this mode due to a configuration conflict, this appears in the show dot1x all command output:

ControlDirection  = In (Disabled due to port settings)

Related Commands

Command
Description

show dot1x [all | interface interface-id]

Displays control-direction port setting status for the specified interface.


dot1x critical (global configuration)

Use the dot1x critical global configuration command on a standalone switch to configure the parameters for the inaccessible authentication bypass feature, also referred to as critical authentication or the authentication, authorization, and accounting (AAA) fail policy. To return to default settings, use the no form of this command.

dot1x critical {eapol | recovery delay milliseconds}

no dot1x critical {eapol | recovery delay}

Syntax Description

eapol

Specify that the switch sends an EAPOL-Success message when the switch puts the critical port in the critical-authentication state.

recovery delay milliseconds

Set the recovery delay period in milliseconds. The range is from 1 to 10000 milliseconds.


Defaults

The switch does not send an EAPOL-Success message to the host when the switch successfully authenticates the critical port by putting the critical port in the critical-authentication state.

The recovery delay period is 1000 milliseconds (1 second).

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SEE

This command was introduced.


Usage Guidelines

Use the eapol keyword to specify that the switch sends an EAPOL-Success message when the switch puts the critical port in the critical-authentication state.

Use the recovery delay milliseconds keyword to set the recovery delay period during which the switch waits to re-initialize a critical port when a RADIUS server that was unavailable becomes available. The default recovery delay period is 1000 milliseconds. A port can be re-initialized every second.

To enable inaccessible authentication bypass on a port, use the dot1x critical interface configuration command. To configure the access VLAN to which the switch assigns a critical port, use the dot1x critical vlan vlan-id interface configuration command.

Examples

This example shows how to set 200 as the recovery delay period on the switch:

Switch# dot1x critical recovery delay 200

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

Related Commands

Command
Description

dot1x critical (interface configuration)

Enables the inaccessible authentication bypass feature, and configures the access VLAN for the feature.

show dot1x

Displays IEEE 802.1x status for the specified port.


dot1x critical (interface configuration)

Use the dot1x critical interface configuration command on a standalone switch to enable the inaccessible-authentication-bypass feature, also referred to as critical authentication or the authentication, authorization, and accounting (AAA) fail policy. You can also configure the access VLAN to which the switch assigns the critical port when the port is in the critical-authentication state. To disable the feature or return to default, use the no form of this command.

dot1x critical [recovery action reinitialize | vlan vlan-id]

no dot1x critical [recovery | vlan]

Syntax Description

recovery action reinitialize

Enable the inaccessible-authentication-bypass recovery feature, and specify that the recovery action is to authenticate the port when an authentication server is available.

vlan vlan-id

Specify the access VLAN to which the switch can assign a critical port. The range is from 1 to 4094.


Defaults

The inaccessible-authentication-bypass feature is disabled.

The recovery action is not configured.

The access VLAN is not configured.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SED

This command was introduced.

12.2(25)SEE

The vlan vlan-id keywords were added.


Usage Guidelines

To specify the access VLAN to which the switch assigns a critical port when the port is in the critical-authentication state, use the vlan vlan-id keywords. The specified type of VLAN must match the type of port, as follows:

If the critical port is an access port, the VLAN must be an access VLAN.

If the critical port is a private VLAN host port, the VLAN must be a secondary private VLAN.

If the critical port is a routed port, you can specify a VLAN, but this is optional.

If the client is running Windows XP and the critical port to which the client is connected is in the critical-authentication state, Windows XP might report that the interface is not authenticated.

If the Windows XP client is configured for DHCP and has an IP address from the DHCP server, receiving an EAP-Success message on a critical port might not re-initiate the DHCP configuration process.

You can configure the inaccessible authentication bypass feature and the restricted VLAN on an IEEE 802.1x port. If the switch tries to re-authenticate a critical port in a restricted VLAN and all the RADIUS servers are unavailable, the switch changes the port state to the critical authentication state, and it remains in the restricted VLAN.

You can configure the inaccessible bypass feature and port security on the same switch port.

Examples

This example shows how to enable the inaccessible authentication bypass feature on port 21:

Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface gigabitethernet0/21
Switch(config-if)# dot1x critical
Switch(config-if)# end
Switch(config)# end
Switch#

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

Related Commands

Command
Description

dot1x critical (global configuration)

Configures the parameters for the inaccessible authentication bypass feature on the switch.

show dot1x [interface interface-id]

Displays IEEE 802.1x status for the specified port.


dot1x default

Use the dot1x default interface configuration command to reset the IEEE 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 IEEE 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(19)EA1

This command was introduced.


Examples

This example shows how to reset the IEEE 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 IEEE 802.1x status for the specified port.


dot1x fallback

Use the dot1xfallback interface configuration command on the switch stack or on a standalone switch to configure a port to use web authentication as a fallback method for clients that do not support IEEE 802.1x authentication. To return to the default setting, use the no form of this command.

dot1x fallback fallback-profile

no dot1x fallback

Syntax Description

fallback-profile

Specify a fallback profile for clients that do not support IEEE 802.1x authentication.


Defaults

No fallback is enabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(35)SE

This command was introduced.


Usage Guidelines

You must enter the dot1x port-control auto interface configuration command on a switch port before entering this command.

Examples

This example shows how to specify a fallback profile to a switch port that has been configured for IEEE 802.1x authentication:

Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# interface gigabitethernet1/0/3
Switch(config-if)# dot1x fallback profile1
Switch(config-fallback-profile)# exit
Switch(config)# end

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 IEEE 802.1x status for the specified port.

fallback profile

Create a web authentication fallback profile.

ip admission

Enable web authentication on a port

ip admission name proxy http

Enable web authentication globally on a switch


dot1x guest-vlan

Use the dot1x guest-vlan interface configuration command to specify an active VLAN as an IEEE 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 IEEE 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(19)EA1

This command was introduced.

12.2(25)SE

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


Usage Guidelines

You can configure a guest VLAN on one of these switch ports:

A static-access port that belongs to a nonprivate VLAN.

A private-VLAN port that belongs to a secondary private VLAN. All the hosts connected to the switch port are assigned to private VLANs, whether or not the posture validation was successful. The switch determines the primary private VLAN by using the primary- and secondary-private-VLAN associations on the switch.

For each IEEE 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) not running IEEE 802.1x authentication. These users might be upgrading their systems for IEEE 802.1x authentication, and some hosts, such as Windows 98 systems, might not be IEEE 802.1x-capable.

When you enable a guest VLAN on an IEEE 802.1x port, the switch assigns clients to a guest VLAN when it 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.

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, the guest VLAN feature is disabled. If the port is already in the guest VLAN state, the port returns to the unauthorized state, and authentication restarts. The EAPOL history is reset upon loss of link.

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. In Cisco IOS Release 12.2(25)SE, you can use the dot1x guest-vlan supplicant global configuration command to enable this behavior.

However, in Cisco IOS Release 12.2(25)SEE, the dot1x guest-vlan supplicant global configuration command is no longer supported. You can use a restricted VLAN to allow clients that failed authentication access to the network by entering the dot1x auth-fail vlan vlan-id interface configuration command.

Any number of non-IEEE 802.1x-capable clients are allowed access when the switch port is moved to the guest VLAN. If an IEEE 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 RADIUS-configured or user-configured access VLAN, and authentication is restarted.

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

You can configure any active VLAN except an Remote Switched Port Analyzer (RSPAN) VLAN, a primary private VLAN, or a voice VLAN as an IEEE 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 IEEE 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 change the settings for restarting the IEEE 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 IEEE 802.1x authentication process (dot1x timeout quiet-period and dot1x timeout tx-period interface configuration commands). The amount to decrease the settings depends on the connected IEEE 802.1x client type.

The switch supports MAC authentication bypass in Cisco IOS Release 12.2(25)SEE and later. When it is enabled on an IEEE 802.1x port, the switch can authorize clients based on the client MAC address when IEEE 802.1x authentication times out while waiting for an EAPOL message exchange. After detecting a client on an IEEE 802.1x port, the switch waits for an Ethernet packet from the client. The switch sends the authentication server a RADIUS-access/request frame with a username and password based on the MAC address. If authorization succeeds, the switch grants the client access to the network. If authorization fails, the switch assigns the port to the guest VLAN if one is specified. For more information, see the "Using IEEE 802.1x Authentication with MAC Authentication Bypass" section in the "Configuring IEEE 802.1x Port-Based Authentication" chapter of the software configuration guide.

Examples

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

Switch(config)# dot1x guest-vlan supplicant
Switch(config)# interface gigabitethernet0/1
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 IEEE 802.1x status for the specified port.


dot1x host-mode

Use the dot1x host-mode interface configuration command to allow a single host (client) or multiple hosts on an IEEE 802.1x-authorized port. Use the multi-domain keyword to enable multidomain authentication (MDA) on an IEEE 802.1x-authorized port. Use the no form of this command to return to the default setting.

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

no dot1x host-mode [multi-host | single-host | multi-domain}

Syntax Description

multi-host

Enable multiple-hosts mode on the switch.

single-host

Enable single-host mode on the switch.

multi-domain

Enable MDA on a switch port.


Defaults

The default is single-host mode.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.2(35)SE

The multi-domain keyword was added.


Usage Guidelines

Use this command to limit an IEEE 802.1x-enabled port to a single client or to attach multiple clients to an IEEE 802.1x-enabled port. In multiple-hosts mode, only one of the attached hosts needs to 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.

Use the multi-domain keyword to enable MDA on a port. MDA divides the port into both a data domain and a voice domain. MDA allows both a data device and a voice device, such as an IP phone (Cisco or non-Cisco), on the same IEEE 802.1x-enabled port.

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 IEEE 802.1x authentication globally, to enable IEEE 802.1x authentication on a port, and to enable multiple-hosts mode:

Switch(config)# dot1x system-auth-control
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# dot1x port-control auto
Switch(config-if)# dot1x host-mode multi-host

This example shows how to globally enable IEEE 802.1x authentication, to enable IEEE 802.1x authentication, and to enable MDA on the specified port:

Switch(config)# dot1x system-auth-control
Switch(config)# interface gigabitethernet3/0/1
Switch(config-if)# dot1x port-control auto
Switch(config-if)# dot1x host-mode multi-domain

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 IEEE 802.1x status for the specified port.


dot1x initialize

Use the dot1x initialize privileged EXEC command to manually return the specified IEEE 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

(Optional) Port to be initialized.


Defaults

There is no default setting.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

Use this command to initialize the IEEE 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 not a no form of this command.

Examples

This example shows how to manually initialize a port:

Switch# dot1x initialize interface gigabitethernet0/22

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 IEEE 802.1x status for the specified port.


dot1x mac-auth-bypass

Use the dot1x mac-auth-bypass interface configuration command to enable the MAC authentication bypass feature. Use the no form of this command to disable MAC authentication bypass feature.

dot1x mac-auth-bypass [eap | timeout activity {value}]

no dot1x mac-auth-bypass

Syntax Description

eap

(Optional) Configure the switch to use Extensible Authentication Protocol (EAP) for authentication.

timeout activity value

(Optional) Configure the number of seconds that a connected host can be inactive before it is placed in an unauthorized state. The range is 1 to 65535.


Defaults

MAC authentication bypass is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SEE

This command was introduced.

12.2(35)SE

The timeout activity value keywords were added.


Usage Guidelines

Unless otherwise stated, the MAC authentication bypass usage guidelines are the same as the IEEE 802.1x authentication guidelines.

If you disable MAC authentication bypass from a port after the port has been authenticated with its MAC address, the port state is not affected.

If the port is in the unauthorized state and the client MAC address is not the authentication-server database, the port remains in the unauthorized state. However, if the client MAC address is added to the database, the switch can use MAC authentication bypass to re-authorize the port.

If the port is in the authorized state, the port remains in this state until re-authorization occurs.

If an EAPOL packet is detected on the interface during the lifetime of the link, the switch determines that the device connected to that interface is an IEEE 802.1x-capable supplicant and uses IEEE 802.1x authentication (not MAC authentication bypass) to authorize the interface.

Clients that were authorized with MAC authentication bypass can be re-authenticated.

You must enable port security before configuring a time out value.

For more information about how MAC authentication bypass and IEEE 802.lx authentication interact, see the "Understanding IEEE 802.1x Authentication with MAC Authentication Bypass" section and the "IEEE 802.1x Authentication Configuration Guidelines" section in the "Configuring IEEE 802.1x Port-Based Authentication" chapter of the software configuration guide.

Examples

This example shows how to enable MAC authentication bypass and to configure the switch to use EAP for authentication:

Switch(config-if)# dot1x mac-auth-bypass eap

This example shows how to enable MAC authentication bypass and to configure the timeout if the connected host is inactive for 30 seconds:

Switch(config-if)# dot1x mac-auth-bypass timeout activity 30

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 IEEE 802.1x status for the specified port.


dot1x max-reauth-req

Use the dot1x max-reauth-req interface configuration command to set the maximum number of times that the switch restarts the authentication process before a port changes 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 changes to the unauthorized state. The range is 0 to 10.


Defaults

The default is 2 times.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(18)SE

This command was introduced.

12.2(25)SEC

The count range was 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.

Examples

This example shows how to set 4 as the number of times that the switch restarts the authentication process before the port changes 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 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 IEEE 802.1x status for the specified port.


dot1x max-req

Use the dot1x max-req interface configuration command to set the maximum number of times that the switch sends an Extensible Authentication Protocol (EAP) frame from the authentication server (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 resends an EAP frame from the authentication server 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(19)EA1

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 5 as the number of times that the switch sends an EAP frame from the authentication server to the client 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 IEEE 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 to allow multiple hosts (clients) on an IEEE 802.1x-authorized port.

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Related Commands

Command
Description

dot1x host-mode

Sets the IEEE 802.1x host mode on a port.

show dot1x

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


dot1x pae

Use the dot1x pae interface configuration command to configure the port as an IEEE 802.1x port access entity (PAE) authenticator. Use the no form of this command to disable IEEE 802.1x authentication on the port.

dot1x pae authenticator

no dot1x pae

Syntax Description

This command has no arguments or keywords.

Defaults

The port is not an IEEE 802.1x PAE authenticator, and IEEE 802.1x authentication is disabled on the port.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SEE

This command was introduced.


Usage Guidelines

Use the no dot1x pae interface configuration command to disable IEEE 802.1x authentication on the port.

When you configure IEEE 802.1x authentication on a port, such as by entering the dot1x port-control interface configuration command, the switch automatically configures the port as an EEE 802.1x authenticator. After the no dot1x pae interface configuration command is entered, the Authenticator PAE operation is disabled.

Examples

This example shows how to disable IEEE 802.1x authentication on the port:

Switch(config-if)# no dot1x pae

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

Related Commands

Command
Description

show dot1x

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

show eap

Displays EAP registration and session information for the switch or for the specified port.


dot1x port-control

Use the dot1x port-control interface configuration command 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 IEEE 802.1x authentication on the port and cause the port to change to the authorized or unauthorized state based on the IEEE 802.1x authentication exchange between the switch and the client.

force-authorized

Disable IEEE 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 IEEE 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(19)EA1

This command was introduced.


Usage Guidelines

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

The IEEE 802.1x standard 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 IEEE 802.1x authentication on a trunk port, an error message appears, and IEEE 802.1x is not enabled. If you try to change the mode of an IEEE 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 IEEE 802.1x authentication on a dynamic port, an error message appears, and IEEE 802.1x authentication is not enabled. If you try to change the mode of an IEEE 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 IEEE 802.1x authentication on a dynamic-access (VLAN Query Protocol [VQP]) port, an error message appears, and IEEE 802.1x authentication is not enabled. If you try to change an IEEE 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 IEEE 802.1x port. If you try to enable IEEE 802.1x authentication on an EtherChannel port, an error message appears, and IEEE 802.1x authentication is not enabled.


Note In software releases earlier than Cisco IOS Release 12.2(20)SE, if IEEE 802.1x authentication 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 IEEE 802.1x authentication on a port that is a SPAN or RSPAN destination port. However, IEEE 802.1x authentication is disabled until the port is removed as a SPAN or RSPAN destination. You can enable IEEE 802.1x authentication on a SPAN or RSPAN source port.

To globally disable IEEE 802.1x authentication on the switch, use the no dot1x system-auth-control global configuration command. To disable IEEE 802.1x authentication on a specific port or to return to the default setting, use the no dot1x port-control interface configuration command.

Examples

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

Switch(config)# interface gigabitethernet0/21
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 IEEE 802.1x status for the specified port.


dot1x re-authenticate

Use the dot1x re-authenticate privileged EXEC command to manually initiate a re-authentication of the specified IEEE 802.1x-enabled port.

dot1x re-authenticate [interface interface-id]

Syntax Description

interface interface-id

(Optional) 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(19)EA1

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 gigabitethernet0/21

Related Commands

Command
Description

dot1x reauthentication

Enables periodic re-authentication of the client.

dot1x timeout reauth-period

Sets the number of seconds between re-authentication attempts.


dot1x re-authentication

This is an obsolete command.

In past releases, the dot1x re-authentication global configuration command was used to set the amount of time between periodic re-authentication attempts.

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Related Commands

Command
Description

dot1x reauthentication

Sets the number of seconds between re-authentication attempts.

show dot1x

Displays IEEE 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 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(19)EA1

This command was introduced.


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 re-authenticate

Manually initiates a re-authentication of all IEEE 802.1x-enabled ports.

dot1x timeout reauth-period

Sets the number of seconds between re-authentication attempts.

show dot1x [interface interface-id]

Displays IEEE 802.1x status for the specified port.


dot1x timeout

Use the dot1x timeout interface configuration command to set IEEE 802.1x timers. Use the no form of this command to return to the default setting.

dot1x timeout {quiet-period seconds | ratelimit-period seconds | reauth-period {seconds | server} | 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.

ratelimit-period seconds

Number of seconds that the switch ignores Extensible Authentication Protocol over LAN (EAPOL) packets from clients that have been successfully authenticated during this duration. The range is 1 to 65535.

reauth-period {seconds | server}

Set the number of seconds between re-authentication attempts.

The keywords have these meanings:

seconds—Sets the number of seconds from 1 to 65535; the default is 3600 seconds.

server—Sets the number of seconds as the value of the Session-Timeout RADIUS attribute (Attribute[27]).

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 IEEE 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 5 to 65535.


Defaults

These are the default settings:

reauth-period is 3600 seconds.

quiet-period is 60 seconds.

tx-period is 5 seconds.

supp-timeout is 30 seconds.

server-timeout is 30 seconds.

rate-limit is 1 second.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.2(20)SE

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

12.2(25)SEC

The range for tx-period keyword was changed, and the reauth-period server keywords were added.

12.2(25)SEE

The ratelimit-period keyword 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.

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 number smaller than the default.

When the ratelimit-period is set to 0 (the default), the switch does not ignore EAPOL packets from clients that have been successfully authenticated and forwards them to the RADIUS server.

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 enable periodic re-authentication and to specify the value of the Session-Timeout RADIUS attribute as the number of seconds between re-authentication attempts:

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

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

This example shows how to set 30 as the number of seconds that the switch ignores EAPOL packets from successfully authenticated clients:

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

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 IEEE 802.1x status for all ports.


duplex

Use the duplex interface configuration command 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 or 100 Mbps). You cannot configure half-duplex mode for interfaces operating at 1000 or 10,000 Mbps.


Defaults

The default is auto for Fast Ethernet and Gigabit Ethernet ports.

The default is full for 100BASE-x (where -x is -BX, -FX, -FX-FE, or - LX) SFP modules.

Duplex options are not supported on the 1000BASE-x (where -x is -BX, -CWDM, -LX, -SX, or -ZX) SFP modules.

For information about which SFP modules are supported on your switch, see the product release notes.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

12.1(20)SE

Support for the half keyword was added for the 100BASE-FX SFP module.


Usage Guidelines

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 the 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.


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.

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.

For guidelines on setting the switch speed and duplex parameters, see the "Configuring Interface Characteristics" chapter in the software configuration guide for this release.

Examples

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

Switch(config)# interface gigabitethernet0/1
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 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-disabled 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 3560 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.


Command Default

Detection is enabled for all causes.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

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 error-disabled 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 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-disabled state.

gbic-invalid

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

Note On the Catalyst 3560 switch, this error refers to an invalid small form-factor pluggable (SFP) error-disabled 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 IEEE 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.


Defaults

Recovery is disabled for all causes.

The default recovery interval is 300 seconds.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.

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 the error-disabled state, an operational state similar to link-down state. If you do not enable the recovery for the cause, the interface stays in the error-disabled state until you enter the shutdown and the no shutdown interface configuration commands. 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 and then the 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 error-disabled recovery timer information.

show interfaces status err-disabled

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


exception crashinfo

Use the exception crashinfo global configuration command to configure the switch to create the extended crashinfo file when the Cisco IOS image fails. Use the no form of this command to disable this feature.

exception crashinfo

no exception crashinfo

Syntax Description

This command has no arguments or keywords.

Defaults

The switch creates the extended crashinfo file.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SEC

This command was introduced.


Usage Guidelines

The basic crashinfo file includes the Cisco IOS image name and version that failed and a list of the processor registers. The extended crashinfo file includes additional information that can help determine the cause of the switch failure.

Use the no exception crashinfo global configuration command to configure the switch to not create the extended crashinfo file.

Examples

This example shows how to configure the switch to not create the extended crashinfo file:

Switch(config)# no exception crashinfo

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

Related Commands

Command
Description

show running-config

Displays the 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.


fallback profile

Use the fallback profile global configuration command on the switch stack or on a standalone switch to create a fallback profile for web authentication. To return to the default setting, use the no form of this command.

fallback profile fallback-profile

no fallback profile

Syntax Description

fallback-profile

Configure a fallback profile for clients that do not support IEEE 802.1x authentication. The clients connect to the port by using web authentication.

ip

Create an IP configuration.

access-group

Specify access control for packets.

admission

Apply an IP admission rule.


Defaults

This command has no default setting.

Command Modes

Global configuration

Command History

Release
Modification

12.2(35)SE

This command was introduced.


Usage Guidelines

The fallback profile is used to define the IEEE 802.1x fallback behavior for IEEE 802.1x ports that do not have supplicants. The only supported behavior is to fall back to web authentication.

Examples

This example shows how to create a fallback profile to be used with web authentication:

Switch# configure terminal
Switch(config)# ip admission name rule1 proxy http  
Switch(config)# fallback profile profile1 
Switch(config)# end
Switch#

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

Related Commands

Command
Description

show dot1x [interface interface-id]

Displays IEEE 802.1x status for the specified port.

dot1x fallback

Configure a port to use web authentication as a fallback method for clients that do not support IEEE 802.1x authentication.

ip admission

Enable web authentication on a switch port

ip admission name proxy http

Enable web authentication globally on a switch


flowcontrol

Use the flowcontrol interface configuration command 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 3560 switch can receive, but not send, 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(19)EA1

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 pause frames, but can operate with an attached device that is required to or is able to send pause frames. The port can 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 gigabitethernet0/21
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 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(19)EA1

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 IEEE 802.1x port. If IEEE 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 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(19)EA1

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 module/{first port} - {last port}, where module is always 0

gigabitethernet module/{first port} - {last port}, where module is always 0

For physical interfaces:

module is always 0

the range is type 0/number - number (for example, gigabitethernet0/1 - 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 gigabitethernet0/1 -2

When you define multiple ranges, you must still enter a space after the first entry and before the comma (,):

interface range fastethernet0/1 - 2, gigabitethernet0/1 - 2

You cannot specify both a macro and an interface range in the same command.

You can also specify a single interface in port-range. The command is then similar to the interface interface-id global configuration command.

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 gigabitethernet0/1 - 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 gigabitethernet0/1 - 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 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(19)EA1

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 IEEE 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 re-instate a deleted SVI by entering the interface vlan vlan-id command for the deleted interface. The interface comes back up, but the previous configuration is gone.

The interrelationship between the number of SVIs configured on a switch 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 to 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 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(19)EA1

This command was introduced.


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 gigabitethernet0/1
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 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(19)EA1

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 gigabitethernet0/1
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 admission

Use the ip admission interface configuration command to enable web authentication. You can also use this command in fallback-profile mode. Use the no form of this command to disable web authentication.

ip admission rule

no ip admission

Syntax Description

rule

Apply an IP admission rule to the interface.


Command Modes

Global configuration

Command History

Release
Modification

12.2(35)SE

This command was introduced.


Usage Guidelines

The ip admission command applies a web authentication rule to a switch port.

Examples

This example shows how to apply a web authentication rule to a switchport:

Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# ip admission rule1

This example shows how to apply a web authentication rule to a fallback profile for use on an IEEE 802.1x enabled switch port.

Switch# configure terminal
Switch(config)# fallback profile profile1
Switch(config)# ip admission name rule1
Switch(config)# end

Related Commands

Command
Description

dot1x fallback

Configure a port to use web authentication as a fallback method for clients that do not support IEEE 802.1x authentication.

fallback profile

Enable web authentication on a port

ip admission name proxy http

Enable web authentication globally on a switch

show ip admission

Displays information about NAC cached entries or the NAC configuration. For more information, see the Network Admission Control Software Configuration Guide on Cisco.com.


ip admission name proxy http

Use the ip admission name proxy http global configuration command to enable web authentication. Use the no form of this command to disable web authentication.

ip admission name proxy http

no ip admission name proxy http

Syntax Description

This command has no arguments or keywords.

Defaults

Web authentication is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.2(35)SE

This command was introduced.


Usage Guidelines

The ip admission name proxy http command globally enables web authentication on a switch.

After you enable web authentication on a switch, use the ip access-group in and ip admission web-rule interface configuration commands to enable web authentication on a specific interface.

Examples

This example shows how to configure only web authentication on a switchport:

Switch# configure terminal
Switch(config) ip admission name http-rule proxy http 
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# ip access-group 101 in
Switch(config-if)# ip admission rule
Switch(config-if)# end

This example shows how to configure IEEE 802.1x authentication with web authentication as a fallback mechanism on a switchport.

Switch# configure terminal
Switch(config)# ip admission name rule2 proxy http 
Switch(config)# fallback profile profile1
Switch(config)# ip access group 101 in
Switch(config)# ip admission name rule2
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# dot1x port-control auto
Switch(config-if)# dot1x fallback profile1
Switch(config-if)# end

Related Commands

Command
Description

dot1x fallback

Configure a port to use web authentication as a fallback method for clients that do not support IEEE 802.1x authentication.

fallback profile

Create a web authentication fallback profile.

ip admission

Enable web authentication on a port

show ip admission

Displays information about NAC cached entries or the NAC configuration. For more information, see the Network Admission Control Software Configuration Guide on Cisco.com.


ip arp inspection filter vlan

Use the ip arp inspection filter vlan global configuration command 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]

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 inventory 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 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

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-disabled recovery feature automatically removes the port from the error-disabled state according to the recovery setting.

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 gigabitethernet0/1
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 inventory 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 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}

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.

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 inventory 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 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 IP services image, formerly known as 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 gigabitethernet0/1
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 inventory interfaces

Displays the trust state and the rate limit of ARP packets for the specified interface or all interfaces.

show inventory 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 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 IP services image, formerly known as 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 inventory 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 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 IP services image, formerly known as 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, or 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 inventory 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 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 IP services image, formerly known as 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 inventory log

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

show inventory 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 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 user EXEC command.

Related Commands

Command
Description

ip dhcp snooping vlan

Enables DHCP snooping on a VLAN.

show ip igmp 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 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 IP services image, formerly known as the enhanced multilayer image (EMI).

Syntax Description

mac-address

Specify a MAC address.

vlan vlan-id

Specify a VLAN number. The range is 1 to 4094.

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 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

Use this command when you are testing or debugging the switch.

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.

Use the show ip dhcp snooping binding privileged EXEC command to display only the 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 
gigabitethernet0/1 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 to configure the DHCP snooping binding database agent. Use the no form of this command to disable the agent, to reset the timeout value, or to reset the write-delay value.

ip dhcp snooping database {{flash:/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 IP services image, formerly known as the enhanced multilayer image (EMI).

Syntax Description

flash:/filename

Specify that the database agent or the binding file is in the flash memory.

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) how long to wait for the database transfer process to finish before stopping.

The default is 300 seconds. The range is 0 to 86400. Use 0 to define an infinite duration, which means to continue trying the transfer indefinitely.

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 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 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 capacities, 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 first write bindings to the binding file at that URL.

Use the ip dhcp snooping database flash:/filename command to save the DHCP snooping binding database in the NVRAM. If you set the ip dhcp snooping database timeout command to 0 seconds and the database is being written to a TFTP file, if the TFTP server goes down, the database agent continues to try the transfer indefinitely. No other transfer can be initiated while this one is in progress. This might be inconsequential because if the server is down, no file can be written to it.

Use the no ip dhcp snooping database command to disable the agent.

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 NVRAM:

Switch(config)# ip dhcp snooping database flash:file01.txt

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 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 is inserted.

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 user 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 allow-untrusted

Use the ip dhcp snooping information option allow-untrusted global configuration command on an aggregation switch to configure it to accept DHCP packets with option-82 information that are received on untrusted ports that might be connected to an edge switch. Use the no form of this command to return to the default setting.

ip dhcp snooping information option allow-untrusted

no ip dhcp snooping information option allow-untrusted

Syntax Description

This command has no arguments or keywords.

Defaults

The switch drops DHCP packets with option-82 information that are received on untrusted ports that might be connected to 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 port 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 allow-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 port. 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 port.


Note Do not enter the ip dhcp snooping information option allow-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.


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 allow-untrusted

You can verify your settings by entering the show ip dhcp snooping user 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 format remote-id

Use the ip dhcp snooping information option format remote-id global configuration command on the switch to configure the option-82 remote-ID suboption. Use the no form of this command to configure the default remote-ID suboption.

ip dhcp snooping information option format remote-id [string ASCII-string | hostname]

no ip dhcp snooping information option format remote-id

Syntax Description

stringASCII-string

Specify a remote ID, using from 1 to 63 ASCII characters (no spaces).

hostname

Specify the switch hostname as the remote ID.


Defaults

The switch MAC address is the remote ID.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SEE

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, the default remote-ID suboption is the switch MAC address. This command allows you to configure either the switch hostname or a string of up to 63 ASCII characters (but no spaces) to be the remote ID.


Note If the hostname exceeds 63 characters, it will be truncated to 63 characters in the remote-ID configuration.


Examples

This example shows how to configure the option- 82 remote-ID suboption:

Switch(config)# ip dhcp snooping information option format remote-id hostname

You can verify your settings by entering the show ip dhcp snooping user EXEC command.

Related Commands

Command
Description

ip dhcp snooping vlan information option format-type circuit-id string

Configures the option-82 circuit-ID suboption.

show ip dhcp snooping

Displays the DHCP snooping configuration.


ip dhcp snooping limit rate

Use the ip dhcp snooping limit rate interface configuration command 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 user 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 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 user 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 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(20)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 user 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 to enable DHCP snooping on a VLAN. Use the no form of this command to return to the default setting.

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 user 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 vlan information option format-type circuit-id string

Use the ip dhcp snooping vlan information option format-type circuit-id string interface configuration command on the switch to configure the option-82 circuit-ID suboption. Use the no form of this command to configure the default circuit-ID suboption.

ip dhcp snooping vlan vlan information option format-type circuit-id string ASCII-string

no ip dhcp snooping vlan vlan information option format-type circuit-id string

Syntax Description

vlan vlan

Specify the VLAN ID. The range is 1 to 4094.

stringASCII-string

Specify a circuit ID, using from 3 to 63 ASCII characters (no spaces).


Defaults

The switch VLAN and the port identifier, in the format vlan-mod-port, is the default circuit ID.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SEE

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, the default circuit-ID suboption is the switch VLAN and the port identifier, in the format vlan-mod-port. This command allows you to configure a string of ASCII characters to be the circuit ID.


Note When configuring a large number of circuit IDs on a switch, consider the impact of lengthy character strings on the NVRAM or flash memory. If the circuit-ID configurations, combined with other data, exceed the capacity of the NVRAM or the flash memory, an error message appears.


Examples

This example shows how to configure the option-82 circuit-ID suboption:

Switch(config-if)# ip dhcp snooping vlan 250 information option format-type circuit-id 
string customerABC-250-0-0

You can verify your settings by entering the show ip dhcp snooping user EXEC command.


Note The show ip dhcp snooping user EXEC command only displays the global command output, including a remote-ID configuration. It does not display any per-interface, per-VLAN string that you have configured for the circuit ID.


Related Commands

Command
Description

ip dhcp snooping information option format remote-id

Configures the option-82 remote-ID suboption.

show ip dhcp snooping

Displays the DHCP snooping configuration.


ip igmp filter

Use the ip igmp filter interface configuration command 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(19)EA1

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 gigabitethernet0/2
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 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, replace the existing group with the new group for which the IGMP report was received.


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(19)EA1

This command was introduced.


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 replaces a randomly selected multicast entry with the received IGMP report.

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 gigabitethernet0/2
Switch(config-if)# ip igmp max-groups 25

This example shows how to configure the switch to replace the existing group with the new group for which the IGMP report was received when the maximum number of entries is in the forwarding table:

Switch(config)# interface gigabitethernet0/1
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 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(19)EA1

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 to globally enable Internet Group Management Protocol (IGMP) snooping on the switch or to enable it on a per-VLAN basis. Use the no form of this command to return to the default setting.

ip igmp snooping [vlan vlan-id]

no ip igmp snooping [vlan vlan-id]

Syntax Description

vlan vlan-id

(Optional) Enable IGMP snooping on the specified VLAN. The range is 1 to 1001 and 1006 to 4094.


Defaults

IGMP snooping is globally enabled on the switch.

IGMP snooping is enabled on VLAN interfaces.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

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 globally disabled, it is disabled on all the existing VLAN interfaces.

VLAN IDs 1002 to 1005 are reserved for Token Ring and FDDI VLANs and cannot be used in IGMP snooping.

Examples

This example shows how to globally enable IGMP snooping:

Switch(config)# ip igmp snooping

This example shows how to enable IGMP snooping on VLAN 1:

Switch(config)# ip igmp snooping vlan 1

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 profile

Displays the snooping configuration.

show ip igmp snooping groups

Displays IGMP snooping multicast information.

show ip igmp snooping mrouter

Displays the IGMP snooping router ports.

show ip igmp snooping querier

Displays the configuration and operation information for the IGMP querier configured on a switch.


ip igmp snooping last-member-query-interval

Use the ip igmp snooping last-member-query-interval global configuration command to enable the Internet Group Management Protocol (IGMP) configurable-leave timer globally or on a per-VLAN basis. Use the no form of this command to return to the default setting.

ip igmp snooping [vlan vlan-id] last-member-query-interval time

no ip igmp snooping [vlan vlan-id] last-member-query-interval

Syntax Description

vlan vlan-id

(Optional) Enable IGMP snooping and the leave timer on the specified VLAN. The range is 1 to 1001 and 1006 to 4094.

time

Interval time out in seconds. The range is 100 to 5000 milliseconds.


t

Defaults

The default timeout setting is 1000 milliseconds.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SEB

This command was introduced.


Usage Guidelines

When IGMP snooping is globally enabled, IGMP snooping is enabled on all the existing VLAN interfaces. When IGMP snooping is globally disabled, IGMP snooping is disabled on all the existing VLAN interfaces.

VLAN IDs 1002 to 1005 are reserved for Token Ring and FDDI VLANs and cannot be used in IGMP snooping.

Configuring the leave timer on a VLAN overrides the global setting.

The IGMP configurable leave time is only supported on devices running IGMP Version 2.

The configuration is saved in NVRAM.

Examples

This example shows how to globally enable the IGMP leave timer for 2000 milliseconds:

Switch(config)# ip igmp snooping last-member-query-interval 2000

This example shows how to configure the IGMP leave timer for 3000 milliseconds on VLAN 1:

Switch(config)# ip igmp snooping vlan 1 last-member-query-interval 3000

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping on the switch or on a VLAN.

ip igmp snooping vlan immediate-leave

Enables IGMP Immediate-Leave processing.

ip igmp snooping vlan mrouter

Configures a Layer 2 port as a multicast router port.

ip igmp snooping vlan static

Configures a Layer 2 port as a member of a group.

show ip igmp snooping

Displays the IGMP snooping configuration.


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 return to the default settings.

ip igmp snooping querier [vlan vlan-id] [address ip-address | max-response-time response-time | query-interval interval-count | tcn query [count count | interval interval] | timer expiry | version version]

no ip igmp snooping querier [vlan vlan-id] [address | max-response-time | query-interval | tcn querycount count | interval interval} | timer expiry | version]

Syntax Description

vlan vlan-id

(Optional) Enable IGMP snooping and the IGMP querier function on the specified VLAN. The range is 1 to 1001 and 1006 to 4094.

address ip-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.

max-response-time response-time

(Optional) Set the maximum time to wait for an IGMP querier report. The range is 1 to 25 seconds.

query-interval interval-count

(Optional) Set the interval between IGMP queriers. The range is 1 to 18000 seconds.

tcn query[count count | interval interval]

(Optional) Set parameters related to Topology Change Notifications (TCNs). The keywords have these meanings:

count count—Set the number of TCN queries to be executed during the TCN interval time. The range is 1 to 10.

interval interval—Set the TCN query interval time. The range is 1 to 255.

timer expiry

(Optional) Set the length of time until the IGMP querier expires. The range is 60 to 300 seconds.

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.

VLAN IDs 1002 to 1005 are reserved for Token Ring and FDDI VLANs and cannot be used in IGMP snooping.

Examples

This example shows how to globally enable the IGMP snooping querier feature:

Switch(config)# 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)# 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)# 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 IGMP snooping multicast information.

show ip igmp snooping mrouter

Displays the IGMP snooping router ports.


ip igmp snooping report-suppression

Use the ip igmp snooping report-suppression global configuration command to enable Internet Group Management Protocol (IGMP) report suppression. Use the no form of this command to disable IGMP report suppression and to 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 multicast 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

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping on the switch or on a VLAN.

show ip igmp snooping

Displays the IGMP snooping configuration of the switch or the VLAN.


ip igmp snooping tcn

Use the ip igmp snooping tcn global configuration command to configure the Internet Group Management Protocol (IGMP) Topology Change Notification (TCN) behavior. Use the no form of this command to return to the default settings.

ip igmp snooping tcn {flood query count count | query solicit}

no ip igmp snooping tcn {flood query count | query solicit}

Syntax Description

flood query count count

Specify the number of IGMP general queries for which the multicast traffic is flooded. The range is 1 to 10.

query solicit

Send an IGMP leave message (global leave) to speed the process of recovering from the flood mode caused during a TCN event.


Defaults

The TCN flood query count is 2.

The TCN query solicitation is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SEB

This command was introduced.


Usage Guidelines

Use ip igmp snooping tcn flood query count global configuration command to control the time that multicast traffic is flooded after a TCN event. If you set the TCN flood query count to 1 by using the ip igmp snooping tcn flood query count command, the flooding stops after receiving 1 general query. If you set the count to 7, the flooding of multicast traffic due to the TCN event lasts until 7 general queries are received. Groups are relearned based on the general queries received during the TCN event.

Use the ip igmp snooping tcn query solicit global configuration command to enable the switch to send the global leave message whether or not it is the spanning-tree root. This command also speeds the process of recovering from the flood mode caused during a TCN event.

Examples

This example shows how to specify 7 as the number of IGMP general queries for which the multicast traffic is flooded:

Switch(config)# no ip igmp snooping tcn flood query count 7

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping on the switch or on a VLAN.

ip igmp snooping tcn flood

Specifies flooding on an interface as the IGMP snooping spanning-tree TCN behavior.

show ip igmp snooping

Displays the IGMP snooping configuration of the switch or the VLAN.


ip igmp snooping tcn flood

Use the ip igmp snooping tcn flood interface configuration command to specify multicast flooding as the Internet Group Management Protocol (IGMP) snooping spanning-tree Topology Change Notification (TCN) behavior. Use the no form of this command to disable the multicast flooding.

ip igmp snooping tcn flood

no ip igmp snooping tcn flood

Syntax Description

This command has no arguments or keywords.

Defaults

Multicast flooding is enabled on an interface during a spanning-tree TCN event.

Command Modes

Interface configuration

Command History

Release
Modification

12.2(25)SEB

This command was introduced.


Usage Guidelines

When the switch receives a TCN, multicast traffic is flooded to all the ports until two general queries are received. If the switch has many ports with attached hosts that are subscribed to different multicast groups, the flooding might exceed the capacity of the link and cause packet loss.

You can change the flooding query count by using the ip igmp snooping tcn flood query count count global configuration command.

Examples

This example shows how to disable the multicast flooding on an interface:

Switch(config)# interface gigabitethernet0/2
Switch(config-if)# no ip igmp snooping tcn flood

You can verify your settings by entering the show ip igmp snooping privileged EXEC command.

Related Commands

Command
Description

ip igmp snooping

Enables IGMP snooping on the switch or on a VLAN.

ip igmp snooping tcn

Configures the IGMP TCN behavior on the switch.

show ip igmp snooping

Displays the IGMP snooping configuration of the switch or the VLAN.


ip igmp snooping vlan immediate-leave

Use the ip igmp snooping immediate-leave global configuration command to enable Internet Group Management Protocol (IGMP) snooping immediate-leave processing on a per-VLAN basis. Use the no form of this command to return to the default setting.

ip igmp snooping vlan vlan-id immediate-leave

no ip igmp snooping vlan vlan-id immediate-leave

Syntax Description

vlan-id

Enable IGMP snooping and the Immediate-Leave feature on the specified VLAN. The range is 1 to 1001 and 1006 to 4094.


Defaults

IGMP immediate-leave processing is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

VLAN IDs 1002 to 1005 are reserved for Token Ring and FDDI VLANs and cannot be used in IGMP snooping.

You should configure the Immediate- Leave feature only 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.

Examples

This example shows how to enable IGMP immediate-leave processing on VLAN 1:

Switch(config)# ip igmp snooping vlan 1 immediate-leave

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 IGMP snooping multicast information.

show ip igmp snooping mrouter

Displays the IGMP snooping router ports.

show ip igmp snooping querier

Displays the configuration and operation information for the IGMP querier configured on a switch.


ip igmp snooping vlan mrouter

Use the ip igmp snooping mrouter global configuration command to add a multicast router port or to configure the multicast learning method. Use the no form of this command to return to the default settings.

ip igmp snooping vlan vlan-id mrouter {interface interface-id | learn {cgmp | pim-dvmrp}}

no ip igmp snooping vlan vlan-id mrouter {interface interface-id | learn {cgmp | pim-dvmrp}}

Syntax Description

vlan-id

Enable IGMP snooping, and add the port in the specified VLAN as the multicast router port. The range is 1 to 1001 and 1006 to 4094.

interface interface-id

Specify the next-hop interface to the multicast router. The keywords have these meanings:

fastethernet interface number—a Fast Ethernet IEEE 802.3 interface.

gigabitethernet interface number—a Gigabit Ethernet IEEE 802.3z interface.

port-channel interface number—a channel interface. The range is 0 to 48.

learn {cgmp | pim-dvmrp}

Specify the multicast router learning method. The keywords have these meanings:

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.


Defaults

By default, there are no multicast router ports.

The default learning method is pim-dvmrp—to snoop IGMP queries and PIM-DVMRP packets.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

VLAN IDs 1002 to 1005 are reserved for Token Ring and FDDI VLANs and cannot be used in IGMP snooping.

The CGMP learn method is useful for reducing control traffic.

The configuration is saved in NVRAM.

Examples

This example shows how to configure a port as a multicast router port:

Switch(config)# ip igmp snooping vlan 1 mrouter interface gigabitethernet0/22

This example shows how to specify the multicast router learning method as CGMP:

Switch(config)# 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 IGMP snooping multicast information.

show ip igmp snooping mrouter

Displays the IGMP snooping router ports.

show ip igmp snooping querier

Displays the configuration and operation information for the IGMP querier configured on a switch.


ip igmp snooping vlan static

Use the ip igmp snooping static global configuration command to enable Internet Group Management Protocol (IGMP) snooping and to statically add a Layer 2 port as a member of a multicast group. Use the no form of this command to remove ports specified as members of a static multicast group.

ip igmp snooping vlan vlan-id static ip-address interface interface-id

no ip igmp snooping vlan vlan-id static ip-address interface interface-id

Syntax Description

vlan-id

Enable IGMP snooping on the specified VLAN. The range is 1 to 1001 and 1006 to 4094.

ip-address

Add a Layer 2 port as a member of a multicast group with the specified group IP address.

interface interface-id

Specify the interface of the member port. The keywords have these meanings:

fastethernet interface number—a Fast Ethernet IEEE 802.3 interface.

gigabitethernet interface number—a Gigabit Ethernet IEEE 802.3z interface.

port-channel interface number—a channel interface. The range is 0 to 48.


Defaults

By default, there are no ports statically configured as members of a multicast group.

Command Modes

Global configuration

Command History

Release
Modification

12.1(19)EA1

This command was introduced.


Usage Guidelines

VLAN IDs 1002 to 1005 are reserved for Token Ring and FDDI VLANs and cannot be used in IGMP snooping.

The configuration is saved in NVRAM.

Examples

This example shows how to statically configure a host on an interface:

Switch(config)# ip igmp snooping vlan 1 static 0100.5e02.0203 interface gigabitethernet0/1
Configuring port gigabitethernet0/1 on group 0100.5e02.0203

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 IGMP snooping multicast information.

show ip igmp snooping mrouter

Displays the IGMP snooping router ports.

show ip igmp snooping querier

Displays the configuration and operation information for the IGMP querier configured on a switch.


ip source binding

Use the ip source binding global configuration command 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 IP services image, formerly known as 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 
gigabitethernet0/1 

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 
gigabitethernet0/1 
Switch(config)# ip source binding 0001.1357.0007 vlan 1 172.20.50.30 interface 
gigabitethernet0/1 

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 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 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

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.


ipv6 access-list

Use the ipv6 access-list global configuration command to define an IPv6 access list and to place the switch in IPv6 access list configuration mode. To remove the access list, use the no form of this command.

ipv6 access-list access-list-name

no ipv6 access-list access-list-name


Note This command is available only if the switch is running the advanced IP services image and you have configured a dual IPv4 and IPv6 Switch Database Management (SDM) template on the switch.


Syntax Description

access-list-name

Name of the IPv6 access list. Names cannot contain a space or quotation mark or begin with a numeric.


Defaults

No IPv6 access list is defined.

Command Modes

Global configuration

Command History

Release
Modification

12.2(25)SED

This command was introduced.


Usage Guidelines

To configure the dual IPv4 and IPv6 template, enter the sdm prefer dual-ipv4-and-ipv6 {default | vlan) global configuration command and reload the switch.

The ipv6 access-list command is similar to the ip access-list command, except that it is IPv6-specific.


Note IPv6 ACLs are defined by a unique name (IPv6 does not support numbered ACLs). An IPv4 ACL and an IPv6 ACL cannot share the same name.


See the ipv6 access-list and permit (IPv6 access-list configuration) commands for more information on filtering IPv6 traffic based on IPv6 option headers and optional, upper-layer protocol-type information. See the "Examples" section for an example of a translated IPv6 ACL configuration.


Note Every IPv6 ACL has implicit permit icmp any any nd-na, permit icmp any any nd-ns, and deny ipv6 any any statements as its last match conditions. The two permit conditions allow ICMPv6 neighbor discovery. To disallow ICMPv6 neighbor discovery and to deny icmp any any nd-na or icmp any any nd-ns, there must be an explicit deny entry in the ACL. For the implicit deny ipv6 any any statement to take effect, an IPv6 ACL must contain at least one entry.

The IPv6 neighbor discovery process makes use of the IPv6 network layer service; therefore, by default, IPv6 ACLs implicitly allow IPv6 neighbor discovery packets to be sent and received on an interface. In IPv4, the Address Resolution Protocol (ARP), which is equivalent to the IPv6 neighbor discovery process, uses a separate data-link layer protocol; therefore, by default, IPv4 ACLs implicitly allow ARP packets to be sent and received on an interface.


Use the ipv6 traffic-filter interface configuration command with the access-list-name argument to apply an IPv6 ACL to an IPv6 interface. You can apply inbound and outbound IPv6 ACLs to Layer 3 physical interfaces or switch virtual interfaces for routed ACLs, but only inbound IPv6 ACLs to Layer 2 interfaces for port ACLs.


Note An IPv6 ACL applied to an interface with the ipv6 traffic-filter command filters traffic that is forwarded by the switch and does not filter traffic generated by the switch.


Examples

This example puts the switch in IPv6 access list configuration mode and configures the IPv6 ACL named list2 and applies the ACL to outbound traffic on an interface. The first ACL entry prevents all packets from the network FE80:0:0:2::/64 (packets that have the link-local prefix FE80:0:0:2 as the first 64 bits of their source IPv6 address) from leaving the interface. The second entry in the ACL permits all other traffic to leave the interface. The second entry is necessary because an implicit deny-all condition is at the end of each IPv6 ACL.

Switch(config)# ipv6 access-list list2
Switch(config-ipv6-acl)# deny FE80:0:0:2::/64 any
Switch(config-ipv6-acl)# permit any any
Switch(config-ipv6-acl)# exit
Switch(config)# interface gigabitethernet0/3
Switch(config-if)# no switchport
Switch(config-if)# ipv6 address 2001::/64 eui-64
Switch(config-if)# ipv6 traffic-filter list2 out


Note IPv6 ACLs that rely on the implicit deny condition or specify a deny any any statement to filter traffic should contain permit statements for link-local addresses to avoid the filtering of protocol packets. Additionally IPv6 ACLs that use deny statements to filter traffic should also use a permit any any statement as the last statement in the list.


Related Commands

Command
Description

deny (IPv6 access-list configuration)

Sets deny conditions for an IPv6 access list.

ipv6 traffic-filter

Filters incoming or outgoing IPv6 traffic on an interface.

permit (IPv6 access-list configuration)

Sets permit conditions for an IPv6 access list.

show ipv6 access-list

Displays the contents of all current IPv6 access lists.


ipv6 mld snooping

Use the ipv6 mld snooping global configuration command without keywords to enable IP version 6 (IPv6) Multicast Listener Discovery (MLD) snooping globally or on the specified VLAN. Use the no form of this command to disable MLD snooping on the switch or the VLAN.

ipv6 mld snooping [vlan vlan-id]

no ipv6 mld snooping [vlan vlan-id]


Note This command is available only if the switch is running the advanced IP services image and you have configured a dual IPv4 and IPv6 Switch Database Management (SDM) template on the switch.


Syntax Description

vlan vlan-id

(Optional) Enable or disable IPv6 MLD snooping on the specified VLAN. The VLAN ID range is 1 to 1001 and 1006 to 4094.


Defaults

MLD snooping is globally disabled on the switch.

MLD snooping is enabled on all VLANs. However, MLD snooping must be globally enabled before VLAN snooping will take place.

Command Modes

Global configuration

Command History