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Catalyst 3750 Metro Switch Command Reference, Release 12.2(55)SE
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Index
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Preface
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Using the Command-Line Interface
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Catalyst 3750 Metro Switch Cisco IOS Commands - aaa through reserved-only
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Catalyst 3750 Metro Switch Cisco IOS Commands - rmon collection stats through show
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Catalyst 3750 Metro Switch Cisco IOS Commands - shutdown through xconnect
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Catalyst 3750 Metro Switch Boot Loader Commands
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Catalyst 3750 Metro Switch Cisco IOS Commands Debug Commands
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Catalyst 3750 Metro Switch Cisco IOS Commands Show Platform Commands
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Acknowledgments for Open-Source Software
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Feedback
Table Of Contents
Catalyst 3750 Metro Switch Cisco IOS Commands
clear ip arp inspection statistics
clear l2protocol-tunnel counters
clear mac address-table move update
clear spanning-tree detected-protocols
deny (ARP access-list configuration)
deny (IPv6 access-list configuration)
deny (MAC access-list configuration)
dot1x supplicant force-multicast
errdisable detect cause small-frame
errdisable recovery cause small-frame
ip arp inspection vlan logging
ip dhcp snooping information option
ip dhcp snooping information option allowed-untrusted
ip dhcp snooping information option format remote-id
ip dhcp snooping vlan information option format-type circuit-id string
ip igmp snooping report-suppression
ip igmp snooping vlan immediate-leave
ip sticky-arp (global configuration)
ip sticky-arp (interface configuration)
ip vrf (interface configuration)
ipv6 dhcp client request vendor
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
location (global configuration)
location (interface configuration)
mac address-table notification
match (access-map configuration)
match (class-map configuration)
mls qos queue-set output buffers
mls qos queue-set output threshold
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 cpu-queue
mls qos srr-queue output dscp-map
permit (ARP access-list configuration)
permit (IPv6 access-list configuration)
permit (MAC-access list configuration)
random-detect exponential-weighting-constant
renew ip dhcp snooping database
Catalyst 3750 Metro Switch Cisco IOS Commands
aaa accounting dot1x
Use the aaa accounting dot1x global configuration command to enable authentication, authorization, and accounting (AAA) accounting and to create method lists defining specific accounting methods on a per-line or per-interface basis for 802.1x sessions. Use the no form of this command to disable 802.1x accounting.
aaa accounting dot1x {name | default} start-stop {broadcast group {name | radius | tacacs+} [group {name | radius | tacacs+} ... ] | group {name | radius | tacacs+} [group {name | radius | tacacs+} ... ]}
no aaa accounting dot1x {name | default}
Syntax Description
Defaults
AAA accounting is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
This command requires access to a RADIUS server.
Note
We recommend that you enter the dot1x reauthentication interface configuration command before configuring 802.1x RADIUS accounting on an interface.
Examples
This example shows how to configure 802.1x accounting:
Switch(config)# aaa accounting dot1x default start-stop group radiusSwitch(config)#
Note
Related Commands
Specifies one or more AAA methods for use on interfaces running 802.1x.
Enables or disables periodic reauthentication.
dot1x test eapol-capable reauth-period
Sets the number of seconds between re-authentication attempts.
aaa authentication dot1x
Use the aaa authentication dot1x global configuration command to specify one or more authentication, authorization, and accounting (AAA) methods for use on ports running IEEE 802.1x. Use the no form of this command to disable authentication.
aaa authentication dot1x {default} method1 [method2...]
no aaa authentication dot1x {default}
Syntax Description
Note
Defaults
No authentication is performed.
Command Modes
Global configuration
Command History
Usage Guidelines
The method argument identifies the list of methods that the authentication algorithm tries in the given sequence to validate the password provided by the client. The only method that is truly 802.1x-compliant is the group radius method, in which the client data is validated against a RADIUS authentication server. The remaining methods enable AAA to authenticate the client by using locally configured data. For example, the local and local-case methods use the username and password that are saved in the configuration file. The enable and line methods use the enable and line passwords for authentication.
If you specify group radius, you must configure the RADIUS server by entering the radius-server host global configuration command.
If you are not using a RADIUS server, you can use the local or local-case methods, which access the local username database to perform authentication. By specifying the enable or line methods, you can supply the clients with a password to provide access to the switch.
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 authentication list for 802.1x. This authentication first tries to contact a RADIUS server. If this action returns an error, the user is allowed access with no authentication.
Switch(config)# aaa new-modelSwitch(config)# aaa authentication dot1x default group radius noneYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
aaa new-model
Enables the AAA access control model. For syntax information, select Cisco IOS Security Command Reference, Release 12.2 > Authentication, Authorization, and Accounting > Authentication Commands.
show running-config
Displays the operating configuration. For syntax information, use this link to the Cisco IOS Release 12.2 Command Reference listing page: http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/prod_command_reference_list.html
Select the Cisco IOS Commands Master List, Release 12.2 to navigate to the command.
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 set the action to the default value, which is to forward.
action {drop | forward}
no action
Syntax Description
drop
Drop the packet when the specified conditions are matched.
forward
Forward the packet when the specified conditions are matched.
Defaults
The default action is to forward packets.
Command Modes
Access-map configuration
Command History
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 vmap4Switch(config-access-map)# match ip address al2Switch(config-access-map)# action forwardSwitch(config-access-map)# exitSwitch(config)# vlan filter vmap4 vlan-list 5-6You can verify your settings by entering the show vlan access-map privileged EXEC command.
Related Commands
archive download-sw
Use the archive download-sw privileged EXEC command to download a new image to the switch and to overwrite or keep the existing image.
archive download-sw {/force-reload | /imageonly | /leave-old-sw | /no-set-boot | /overwrite | /reload | /safe} source-url
Syntax Description
Note
Defaults
The current software image is not overwritten with the downloaded image.
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
Usage Guidelines
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.
Examples
This example shows how to download a new image from a TFTP server at 172.20.129.10 and overwrite the image on the switch:
Switch# archive download-sw /overwrite tftp://172.20.129.10/test-image.tarThis 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.tarThis 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.tarRelated Commands
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
Defaults
None
Command Modes
Privileged EXEC
Command History
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-configsThis example shows how to display the contents of the image-tv0-m.tar file that is in flash memory. The contents of the tar file are displayed on the screen.
Switch# archive tar /table flash:image-tv0-m.tarinfo (219 bytes)image-tv0-mz-121/ (directory)image-tv0-mz-121/html/ (directory)image-tv0-mz-121/html/foo.html (0 bytes)image-tv0-mz-121/image-tv0-mz-121.bin (610856 bytes)image-tv0-mz-121/info (219 bytes)info.ver (219 bytes)This example shows how to display only the image-tv0-mz-121/html directory and its contents:
Switch# archive tar /table flash:image-tv0-m.tar image-tv0-mz-121/htmlimage-tv0-mz-121/html/ (directory)image-tv0-mz-121/html/foo.html (0 bytes)This example shows how to extract the contents of a tar file on the TFTP server at 172.20.10.30. This command extracts just the new-configs directory into the root directory on the local flash file system. The remaining files in the saved.tar file are ignored.
Switch# archive tar /xtract tftp://172.20.10.30/saved.tar flash:/ new-configsRelated Commands
Downloads a new image to the switch.
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 destination-url
Syntax Description
Defaults
Uploads the currently running image from the flash: file system.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
The files are uploaded in this sequence: the Cisco IOS image and the info file. 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.tarRelated Commands
Downloads a new image to the switch.
Creates a tar file, lists the files in a tar file, or extracts the files from a tar file.
arp access-list
Use the arp access-list global configuration command on the switch stack or on a standalone switch to define an Address Resolution Protocol (ARP) access control list (ACL) or to add clauses to the end of a previously defined list. Use the no form of this command to delete the specified ARP access list.
arp access-list acl-name
no arp access-list acl-name
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
Defaults
No ARP access lists are defined.
Command Modes
Global configuration
Command History
Usage Guidelines
After entering the arp access-list command, you enter ARP access-list configuration mode, and these configuration commands are available:
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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-hostsSwitch(config-arp-nacl)# permit ip host 1.1.1.1 mac host 00001.0000.abcdSwitch(config-arp-nacl)# endYou can verify your settings by entering the show arp access-list privileged EXEC command.
Related Commands
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
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 queues and egress queue-sets. Table 2-1 shows the default settings.
Table 2-1 Traffic Types, Packet Labels, and Queues
TrafficDSCP3
46
24, 26
48
56
34
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CoS4
5
3
6
7
3
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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
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 queue-set.
Table 2-3 Auto-QoS Configuration for the Egress Queue-Set
Priority (shaped)
1
5
10 percent
10 percent
SRR shared
2
3, 6, 7
10 percent
10 percent
SRR shared
3
2, 4
60 percent
26 percent
SRR shared
4
0, 1
20 percent
54 percent
1 On an enhanced-services (ES) port, the srr-queue bandwidth shape interface configuration command is not part of the generated auto qos voip command list.
Command Modes
Interface configuration
Command History
12.1(14)AX
This command was introduced.
12.2(25)EY
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 inbound traffic for QoS.
In releases earlier than Cisco IOS Release 12.2(25)EY, auto-QoS configures the switch only for VoIP with Cisco IP Phones on switch ports.
In Cisco IOS Release 12.2(25)EY 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
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:
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You can enable auto-QoS on static, dynamic-access, 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.
To display the QoS commands that are automatically generated when auto-QoS is enabled or disabled, 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.
Note
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 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).
On a port on which the auto qos voip command is enabled, the queue-set ID that is generated depends on the interface:
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Examples
This example shows how to enable auto-QoS on a port and to trust the QoS labels received in inbound packets when the switch or router connected to a port is a trusted device:
Switch(config)# interface gigabitethernet1/0/1Switch(config-if)# auto qos voip trustYou can verify your settings by entering the show auto qos interface interface-id privileged EXEC command.
Related Commands
Enables debugging of the auto-QoS feature.
Defines the default CoS value of a port or assigns the default CoS to all inbound 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.
Allocates buffers to a queue-set.
Assigns SRR weights to an ingress queue.
Allocates the buffers between the ingress queues.
Maps CoS values to an ingress queue or maps CoS values to a queue and to a threshold ID.
Maps DSCP values to an ingress queue or maps DSCP values to a queue and to a threshold ID.
Configures the ingress priority queue and guarantees bandwidth.
Maps CoS values to an egress queue or maps CoS values to a queue and to a threshold ID.
Maps DSCP values to an egress queue or maps DSCP values to a queue and to a threshold ID.
Configures the port trust state.
Maps a port to a queue-set.
Displays the initial configuration that is generated by the auto-QoS feature.
Displays QoS information at the port level.
Assigns the shaped weights and enables bandwidth shaping on the four egress queues mapped to a standard port.
Assigns the shared weights and enables bandwidth sharing on the four egress queues mapped to a port.
bandwidth
Use the bandwidth policy-map class configuration command to specify or modify the minimum bandwidth provided to a class belonging to a hierarchical policy map attached to an enhanced-services (ES) port. Use the no form of this command to return to the default setting.
bandwidth {bandwidth-kbps | percent percent}
no bandwidth
Syntax Description
Defaults
No bandwidth is specified.
Command Modes
Policy-map class configuration
Command History
12.1(14)AX
This command was introduced.
12.2(25)EY
Hierarchical service policies can be applied to inbound traffic received on an ES port.
Usage Guidelines
Use the bandwidth command only in a hierarchical policy map attached to an ES port. This command is not valid for the class-default class in a physical-level policy map.
Use the bandwidth command when you configure a policy map for a class defined by the class-map global configuration command. The bandwidth command specifies the minimum bandwidth for traffic in that class when there is traffic congestion in the switch. If the switch is not congested, the class receives more bandwidth than you specify with this command. Class-based weighted fair queueing (CBWFQ) derives the weight for packets belonging to the class from the bandwidth allocated to the class. CBWFQ then uses the weight to ensure that the queue for the class is serviced fairly.
Note
These restrictions apply to the bandwidth command:
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•
•
•
•
•
When you configure the bandwidth command in a class policy, you must also configure the bandwidth or shape policy-map class configuration command in the parent VLAN-level policy.
You must configure the bandwidth or the shape policy-map class configuration command before you configure either the queue-limit or the random-detect policy-map class configuration command in a class policy.
You cannot use the bandwidth, queue-limit, random-detect, and the shape policy-map class configuration commands with the priority policy-map class configuration command in the same class within the same policy map. However, you can use these commands in the same policy map.
When you use the service-policy interface configuration command to attach the policy map containing class configurations to an ES port, the switch determines the available bandwidth.
Examples
This example shows how to set the minimum bandwidth to 2000 kbps for a class called silver-class. The class already exists in the switch configuration.
Switch(config)# policy-map polmap6Switch(config-pmap)# class silver-classSwitch(config-pmap-c)# bandwidth 2000This example shows how to guarantee 30 percent of the bandwidth for class1 and 25 percent of the bandwidth for class2 when CBWFQ is configured. A policy map with two classes is created and is then attached to an ES port.
Switch(config)# policy-map policy1Switch(config-pmap)# class class1Switch(config-pmap-c)# bandwidth percent 50Switch(config-pmap-c)# exitSwitch(config-pmap)# class class2Switch(config-pmap-c)# bandwidth percent 25Switch(config-pmap-c)# exitSwitch(config-pmap)# endSwitch(config)# interface gigabitethernet1/1/1Switch(config-if)# service-policy input policy1This example shows how bandwidth is guaranteed if low-latency queueing (LLQ) and CBWFQ are configured. In this example, LLQ is enabled in a class called voice1.
Switch(config)# policy-map policy1Switch(config-pmap)# class class1Switch(config-pmap-c)# bandwidth percent 50Switch(config-pmap-c)# exitSwitch(config-pmap)# class class2Switch(config-pmap-c)# bandwidth percent 25Switch(config-pmap-c)# exitSwitch(config-pmap)# class voice1Switch(config-pmap-c)# prioritySwitch(config-pmap-c)# exitSwitch(config-pmap)# endSwitch(config)# interface gigabitethernet1/1/1Switch(config-if)# service-policy output policy1You can verify your settings by entering the show policy-map privileged EXEC command.
Related Commands
boot config-file
Use the boot config-file global configuration command to specify the filename that software 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
Defaults
The default configuration file is flash:config.text.
Command Modes
Global configuration
Command History
Usage Guidelines
Filenames and directory names are case sensitive.
This command changes the setting of the CONFIG_FILE environment variable. For more information, see Appendix A, "Catalyst 3750 Metro Switch Boot Loader Commands."
Related Commands
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
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
This command changes the setting of the ENABLE_BREAK environment variable. For more information, see Appendix A, "Catalyst 3750 Metro Switch Boot Loader Commands."
Related Commands
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
Defaults
No helper files are loaded.
Command Modes
Global configuration
Command History
Usage Guidelines
This variable is used only for internal development and testing.
Filenames and directory names are case sensitive.
This command changes the setting of the HELPER environment variable. For more information, see Appendix A, "Catalyst 3750 Metro Switch Boot Loader Commands."
Related Commands
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 helper image. If this is not set, the file specified by the CONFIG_FILE environment variable is used by all versions of software 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
Usage Guidelines
This variable is used only for internal development and testing.
Filenames and directory names are case sensitive.
This command changes the setting of the HELPER_CONFIG_FILE environment variable. For more information, see Appendix A, "Catalyst 3750 Metro Switch Boot Loader Commands."
Related Commands
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
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 Appendix A, "Catalyst 3750 Metro Switch Boot Loader Commands."
Related Commands
boot private-config-file
Use the boot private-config-file global configuration command to specify the filename that software 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
Defaults
The default configuration file is private-config.
Command Modes
Global configuration
Command History
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 pconfigRelated Commands
boot system
Use the boot system global configuration command to specify the 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
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 Appendix A, "Catalyst 3750 Metro Switch Boot Loader Commands."
Related Commands
channel-group
Use the channel-group interface configuration command to assign a port to an EtherChannel group and to enable an EtherChannel mode. Use the no form of this command to remove a 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 onSyntax Description
Defaults
No channel groups are assigned.
No mode is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
For Layer 2 EtherChannels, you do not have to create a port-channel 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 when the channel group gets its first physical port if the logical interface is not already created. If you create the port-channel 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 apply to all the physical ports assigned to the port-channel. 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, for example, spanning-tree commands or commands to configure a Layer 2 EtherChannel as a trunk.
If you do not specify non-silent with the auto or desirable mode, silent is assumed. The silent mode is used when the switch is connected to a device that is not PAgP-capable and seldom, if ever, sends packets. A example of a silent partner is a file server or a packet analyzer that is not generating traffic. In this case, running PAgP on a physical port prevents that port from ever becoming operational. However, it allows PAgP to operate, to attach the port to a channel group, and to use the port for transmission. Both ends of the link cannot be set to silent.
With the on mode, a usable EtherChannel exists only when a port group in the on mode is connected to another port group in the on mode.
Caution
Note
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 member of an EtherChannel as an 802.1x port. If 802.1x is enabled on a not-yet active port of an EtherChannel, the port does not join the EtherChannel.
Note
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 guide for this release.
Caution
Examples
This example shows how to configure EtherChannel. It assigns ports as static-access ports in VLAN 10 to channel 5 with the PAgP mode desirable.
Switch# configure terminalSwitch(config)# interface range fastethernet1/0/4 -5Switch(config-if-range)# switchport mode accessSwitch(config-if-range)# switchport access vlan 10Switch(config-if-range)# channel-group 5 mode desirableSwitch(config-if-range)# endThis example shows how to configure EtherChannel. It assigns ports as static-access ports in VLAN 10 to channel 5 with the LACP mode active.
Switch# configure terminalSwitch(config)# interface range fastethernet1/0/4 -5Switch(config-if-range)# switchport mode accessSwitch(config-if-range)# switchport access vlan 10Switch(config-if-range)# channel-group 5 mode activeSwitch(config-if-range)# endYou can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
Restricts the protocol used on a port to manage channeling.
Accesses or creates the port channel.
Displays EtherChannel information for a channel.
Displays LACP channel-group information.
Displays PAgP channel-group information.
show running-config
Displays the operating configuration. For syntax information, use this link to the Cisco IOS Release 12.2 Command Reference listing page: http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/prod_command_reference_list.html
Select the Cisco IOS Commands Master List, Release 12.2 to navigate to the command.
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
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 lacpYou can verify your settings by entering the show etherchannel [channel-group-number] protocol privileged EXEC command.
Related Commands
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 specify the name of the class whose traffic policy you want to create or change. Use the no form of this command to delete an existing class from a policy map.
class {class-map-name | class-default}
no class {class-map-name | class-default}
Syntax Description
class-map-name
Name of the class map.
class-default
System default class that matches unclassified packets.
Defaults
No classes are defined.
Command Modes
Policy-map configuration
Command History
12.1(14)AX
This command was introduced.
12.2(55)SE
The class-default keyword was added.
Usage Guidelines
Before using the class command, you must create a class map for matching packets to the class by using the class-map global configuration command. You also 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 traffic policy for new classes or modify a traffic policy for any existing classes in that policy map. The class name that you specify with the class command in the policy map ties the characteristics for that class—that is, its policy—to the class map and its match criteria, as configured through the class-map global configuration command. You attach the policy map to a port by using the service-policy interface configuration command.
After you enter the class command, the switch enters policy-map class configuration mode, and these configuration commands are available:
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The switch supports up to eight classes, including the default class, in a policy map. Packets that fail to meet any of the matching criteria are classified as members of the default traffic class. You configure the default traffic class by specifying class-default as the class name in the class policy-map class configuration command. You can manipulate the default traffic class (for example, set policies to police or to shape it) just like any other traffic class, but you cannot delete it.
Within a policy map, the class-default applies to all traffic that is not explicitly matched within the policy map but that does match the parent policy. If no parent policy is configured, the parent policy represents the physical port. In the physical-level policy map, class-default is the only class that can be configured.
In a hierarchical policy map attached to an ES port, you define a class policy to use either tail drop or WRED packet drop by using either the queue-limit policy-map class configuration command or the random-detect policy-map class configuration command, respectively. You cannot use the queue-limit and random-detect commands in the same class policy, but they can be used in two class policies in the same policy map.
In a hierarchical policy map attached to an ES port, you must configure the bandwidth or the shape policy-map class configuration command before you configure either the queue-limit or the random-detect policy-map class configuration command in a class policy.
When you configure a policy for a class, specify its bandwidth, and attach the policy map to an ES port, class-based weighted fair queueing (CBWFQ) determines if the bandwidth requirement of the class can be satisfied. If so, CBWFQ creates the necessary internal data structures to maintain the state for the class and allocates a queue for it. If CBWFQ decides that the bandwidth requirement for the class cannot be satisfied, an error message appears, and the policy is not attached. When a class is removed, available bandwidth for the port is incremented by the amount previously allocated to the class.
To return to policy-map configuration mode, use the exit command. To return to privileged EXEC mode, use the end command.
You can configure a default class by using the class class-default policy-map configuration command. Unclassified traffic (traffic that does not meet the match criteria specified in the traffic classes) is treated as default traffic.
Examples
This example shows how to create a policy map called policy1. When attached to an ingress port, the policy matches all the inbound traffic defined in class1, sets the IP DSCP to 10, and polices the traffic at an average rate of 1 Mbps and bursts of 20 KB. Traffic exceeding the profile is marked down to a Traffic exceeding the profile is marked down to a DSCP value obtained from the policed-DSCP map and then sent.
Switch(config)# class-map class1Switch(config-cmap)# exitSwitch(config)# policy-map policy1Switch(config-pmap)# class class1Switch(config-pmap-c)# set ip dscp 10Switch(config-pmap-c)# police 1000000 20000 exceed-action policed-dscp-transmitSwitch(config-pmap-c)# exitSwitch(config-pmap)# exitSwitch(config)# interface fastethernet1/0/4Switch(config-if)# service-policy input policy1This example configures two class policies included in the egress policy map called policy1. Class1 specifies a policy for 802.1Q tunneling traffic that matches packets based on the outer VLAN ID (VLAN 2) and the inner VLAN IDs (3 to 8).
Switch(config)# class-map match-all class1Switch(config-cmap)# match vlan 2Switch(config-cmap)# match vlan inner 3 - 8Switch(config-cmap)# exitSwitch(config)# policy-map policy1Switch(config-pmap)# class class1Switch(config-pmap-c)# bandwidth 2000Switch(config-pmap-c)# queue-limit 40Switch(config-pmap-c)# exitSwitch(config-pmap)# exitSwitch(config)# interface gigabitethernet1/1/1Switch(config-if)# service-policy output policy1For class1, a minimum of 2000 kbps of bandwidth is expected to be delivered to this class in the event of congestion. The queue reserved for this class can contain 40 packets before tail drop occurs.
This example shows how to shape the default class. This configuration associates a class-level policy map with a VLAN-level policy map and then associates the VLAN-level policy map with a physical-level policy map.
Switch(config)# class-map my-classSwitch(config-cmap)# match ip precedence 1Switch(config-cmap)# exitSwitch(config)# class-map my-logical-classSwitch(config-cmap)# match vlan 5Switch(config-cmap)# exitSwitch(config)# policy-map my-class-policySwitch(config-pmap)# class my-classSwitch(config-pmap-c)# set ip precedence 2Switch(config-pmap-c)# exitSwitch(config-pmap)# exitSwitch(config)# policy-map my-logical-policySwitch(config-pmap)# class my-logical-classSwitch(config-pmap-c)# shape average 400000000Switch(config-pmap-c)# service-policy my-class-policySwitch(config-pmap-c)# exitSwitch(config-pmap)# exitSwitch(config)# policy-map my-physical-policySwitch(config-pmap)# class class-defaultSwitch(config-pmap-c)# shape average 500000000Switch(config-pmap-c)# service-policy my-logical-policyThis example shows how to create a hierarchical class-level policy map with two traffic classes. One of the classes has a class-level classification and a two-rate policer, and the other is the default traffic class. Packets that fail to meet the matching criteria are classified as members of the default traffic class, and the IP precedence in this traffic is reset to 0.
Switch(config)# class-map match-all classprece1Switch(config-cmap)# match ip precedence 1Switch(config-cmap)# exitSwitch-config)# policy-map precedencepoliceSwitch(config-pmap)# class classprece1Switch(config-pmap-c)# police cir 100000000 pir 200000000 conform-action set-prec-transmit 2 exceed-action set-prec-transmit 3 violate-action set-prec-transmit 4Switch(config-pmap-c)# exitSwitch(config-pmap)# class class-defaultSwitch(config-pmap-c)# set ip precedence 0In the previous hierarchical QoS example, the first traffic class has only one match statement. However, hierarchical policy maps can support multiple match statements.
This example shows how to configure a default traffic class to a policy map:
Switch# configure terminalSwitch(config)# class-map cm-3Switch(config-cmap)# match ip dscp 30Switch(config-cmap)# match protocol ipv6Switch(config-cmap)# exitSwitch(config)# class-map cm-4Switch(config-cmap)# match ip dscp 40Switch(config-cmap)# match protocol ipSwitch(config-cmap)# exitSwitch(config)# policy-map pm3Switch(config-pmap)# class class-defaultSwitch(config-pmap-c)# set dscp 10Switch(config-pmap-c)# exitSwitch(config-pmap)# class cm-3Switch(config-pmap-c) set dscp 4Switch(config-pmap-c)# exitSwitch(config-pmap)# class cm-4Switch(config-pmap-c)# trust cosSwitch(config-pmap-c)# exitSwitch(config-pmap)# exitYou can verify your settings by entering the show policy-map privileged EXEC command.This example shows how the default traffic class is automatically placed at the end of policy-map pm3 even though class-default was configured first:
Switch# show policy-map pm3Policy Map pm3Class cm-3set dscp 4Class cm-4trust cosClass class-defaultset dscp 10Switch#Related Commands
class-map
Use the class-map global configuration command to create a class map to be used for matching packets to the class whose name you specify and to enter class-map configuration mode. Use the no form of this command to delete an existing class map and to return to global configuration mode.
class-map [match-all | match-any] class-map-name
no class-map [match-all | match-any] class-map-name
Syntax Description
Defaults
No class maps are defined.
If neither the match-all nor the match-any keyword is specified, the default is match-all.
Command Modes
Global configuration
Command History
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. Packets are checked against the match criteria configured for a class map to decide if the packet belongs to that class. If a packet matches the specified criteria, the packet is considered a member of the class and is forwarded according to the quality of service (QoS) specifications set in the traffic policy.
You can create up to 4093 class maps.
After you enter the class-map command, the switch enters class-map configuration mode, and these configuration commands are available:
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Only one access control list (ACL) can be configured in a class map. The ACL can have multiple access control entries (ACEs). Class maps that contain ACLs are not supported in an egress policy attached to an enhanced-services (ES) port or in a hierarchical ingress policy attached to an ES port.
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 ip any any dscp 10Switch(config)# class-map class1Switch(config-cmap)# match access-group 103Switch(config-cmap)# exitThis example shows how to delete the class1 class map:
Switch(config)# no class-map class1You can verify your settings by entering the show class-map privileged EXEC command.
Related Commands
clear ip arp inspection log
Use the clear ip arp inspection log privileged EXEC command on the switch stack or on a standalone switch to clear the dynamic Address Resolution Protocol (ARP) inspection log buffer.
clear ip arp inspection log
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
This command has no arguments or keywords.
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
Examples
This example shows how to clear the contents of the log buffer:
Switch# clear ip arp inspection logYou can verify that the log was cleared by entering the show ip arp inspection log privileged command.
Related Commands
clear ip arp inspection statistics
Use the clear ip arp inspection statistics privileged EXEC command on the switch stack or on a standalone switch to clear the dynamic Address Resolution Protocol (ARP) inspection statistics.
clear ip arp inspection statistics [vlan vlan-range]
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
Examples
This example shows how to clear the statistics for VLAN 1:
Switch# clear ip arp inspection statistics vlan 1You can verify that the statistics were deleted by entering the show ip arp inspection statistics vlan 1 privileged EXEC command.
Related Commands
show ip arp inspection statistics
Displays statistics for forwarded, dropped, MAC validation failure, and IP validation failure packets for all VLANs or the specified VLAN.
clear ip dhcp snooping
Use the clear ip dhcp snooping privileged EXEC command to clear the DHCP snooping binding database, the DHCP snooping binding database agent statistics, or the DHCP snooping statistics counters.
clear ip dhcp snooping {binding {* | ip-address | interface interface-id | vlan vlan-id} | database statistics | statistics}
Syntax Description
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
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 statisticsYou can verify that the statistics were cleared by entering the show ip dhcp snooping database privileged EXEC command.
This example shows how to clear the DHCP snooping statistics counters:
Switch# clear ip dhcp snooping statisticsYou can verify that the statistics were cleared by entering the show ip dhcp snooping statistics user EXEC command.
Related Commands
clear ipv6 dhcp conflict
Use the clear ipv6 dhcp conflict privileged EXEC command to clear an address conflict from the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server database.
clear ipv6 dhcp conflict {* | IPv6-address}
Note
Syntax Description
*
Clear all address conflicts.
IPv6-address
Clear the host IPv6 address that contains the conflicting address.
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
To configure the dual IPv4 and IPv6 template, enter the sdm prefer dual-ipv4-and-ipv6 {default | routing | vlan} global configuration command, and reload the switch.
When you configure the DHCPv6 server to detect conflicts, it uses ping. The client uses neighbor discovery to detect clients and reports to the server through a DECLINE message. If an address conflict is detected, the address is removed from the pool and is not assigned until the administrator removes the address from the conflict list.
If you use the asterisk (*) character as the address parameter, DHCP clears all conflicts.
Examples
This example shows how to clear all address conflicts from the DHCPv6 server database:
Switch# clear ipv6 dhcp conflict *Related Commands
Displays address conflicts found by a DHCPv6 server, or reported through a DECLINE message from a client.
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 for which protocol counters are to be cleared. The interface can be a physical interface or a port channel.
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
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 a port:
Switch # clear l2protocol-tunnel counters gigabitethernet1/0/2You can verify that the information was deleted by entering the show l2protocol-tunnel privileged EXEC command.
Related Commands
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 12.
counters
Clear traffic counters.
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
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 countersThis example shows how to clear LACP traffic counters for group 4:
Switch# clear lacp 4 countersYou can verify that the information was deleted by entering the show lacp counters or the show lacp 4 counters privileged EXEC command.
Related Commands
clear mac address-table
Use the clear mac address-table privileged EXEC command to delete from the MAC address table all dynamic MAC addresses, a specific dynamic MAC 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
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
Examples
This example shows how to remove a specific MAC address from the dynamic address table:
Switch# clear mac address-table dynamic address 0008.0070.0007You can verify that the information was deleted by entering the show mac address-table privileged EXEC command.
Related Commands
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
Examples
This example shows how to clear the mac address-table move update related counters.
Switch# clear mac address-table move updateYou can verify that the information was cleared by entering the show mac address-table move update privileged EXEC command.
Related Commands
Configures MAC address-table move update on the switch.
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 12.
counters
Clear traffic counters.
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
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 countersThis example shows how to clear PAgP traffic counters for group 10:
Switch# clear pagp 10 countersYou can verify that information was deleted by entering the show pagp privileged EXEC command.
Related Commands
clear rep counters
Use the clear rep counters privileged EXEC command to clear Resilient Ethernet Protocol (REP) counters for the specified interface or all interfaces.
clear rep counters [interface interface-id]
Syntax Description
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
You can clear all REP counters by using the clear rep counters command, or you can clear only the counters for the interface by using the clear rep counters interface interface-id command.
When you enter the clear rep counters command, only the counters visible in the output of the show interface rep detail command are cleared. SNMP visible counters are not cleared as they are read-only.
Examples
This example shows how to clear all REP counters for all REP interfaces:
Switch# clear rep countersYou can verify that REP information was deleted by entering the show interfaces rep detail privileged EXEC command.
Related Commands
show interfaces rep detail
Displays detailed REP configuration and status information.
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
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
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 countersRelated Commands
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
Defaults
No default is defined.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
A switch running the rapid per-VLAN spanning-tree plus (rapid-PVST+) protocol or the Multiple Spanning Tree Protocol (MSTP) supports a built-in protocol migration mechanism that enables it to interoperate with legacy 802.1D switches. If a rapid-PVST+ switch or an MSTP switch receives a legacy 802.1D configuration bridge protocol data unit (BPDU) with the protocol version set to 0, it sends only 802.1D BPDUs on that interface. A multiple spanning-tree (MST) switch can also detect that an interface is at the boundary of a region when it receives a legacy BPDU, an MST BPDU (version 3) associated with a different region, or a rapid spanning-tree (RST) BPDU (version 2).
However, the switch does not automatically revert to the rapid-PVST+ or the MSTP mode if it no longer receives 802.1D BPDUs. It cannot detect 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 gigabitethernet1/0/1Related Commands
Displays spanning-tree state information.
Overrides the default link-type setting and enables rapid spanning-tree transitions to the forwarding state.
clear vmps statistics
Use the clear vmps statistics privileged EXEC command 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
Examples
This example shows how to clear VLAN Membership Policy Server (VMPS) statistics:
Switch# clear vmps statisticsYou can verify that information was deleted by entering the show vmps statistics privileged EXEC command.
Related Commands
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
Examples
This example shows how to clear the VTP counters:
Switch# clear vtp countersYou can verify that information was deleted by entering the show vtp counters privileged EXEC command.
Related Commands
Displays general information about the VTP management domain, status, and counters.
cpu traffic qos cos
Use the cpu traffic qos cos command in global configuration mode to mark the class of service (CoS) value of CPU traffic. To return to the default value, use the no form of this command.
cpu traffic qos cos {cos-value | trust}
no cpu traffic qos cos {cos-value | trust}
Syntax Description
Command Default
Control plane (CPU) traffic is not marked for QoS.
Command Modes
Global configuration
Command History
Usage Guidelines
This feature must be configured globally for a switch; it cannot be configured per-port or per-protocol.
Enter each cpu traffic qos marking action on a separate line.
The trust keyword configures the switch to trust the incoming CoS, DSCP, or precedence value and mark the packet according to the global map configuration.
When you configure the switch to trust CoS, the configuration applies to both IP and non-IP traffic.
When you configure the switch to trust or change DSCP or precedence, but not CoS, the configuration applies only to IP traffic.
When you configure the switch to trust CoS and trust or change DSCP or precedence, then trust CoS applies to non-IP traffic and trust or change DSCP or precedence applies to IP traffic.
The cpu traffic qos cos global configuration command configures CoS marking for CPU-generated traffic by either trusting CoS or specifying a CoS value, but not both. A new configuration overwrites the existing configuration.
Examples
This example shows how to specify a CoS value for CPU-generated IP traffic (including IP-SLA and TWAMP):
Switch(config)# cpu traffic qos cos 2This example shows how to configure the switch to trust the CoS value of the incoming packet:
Switch(config)# cpu traffic qos cos trustRelated Commands
cpu traffic qos dscp
Use the cpu traffic qos dscp command in global configuration mode to configure a differentiated services code point (DSCP) value for CPU traffic. To return to the default value, use the no form of this command.
cpu traffic qos dscp {dscp-value | trust | dscp-mutation mutation-map-name}
no cpu traffic qos dscp {dscp-value | trust | dscp-mutation mutation-map-name}
Syntax Description
Command Default
Control plane (CPU) traffic is not marked for QoS.
Command Modes
Global configuration
Command History
Usage Guidelines
This feature must be configured globally for a switch; it cannot be configured per-port or per-protocol.
Enter each cpu traffic qos marking action on a separate line.
The trust keyword configures the switch to trust the incoming CoS, DSCP, or precedence value and mark the packet according to the global map configuration.
The mutation keyword configures the switch to change the incoming value according to the global mutation-map configuration.
When you configure the switch to trust CoS, the configuration applies to both IP and non-IP traffic.
When you configure the switch to trust or change DSCP or precedence, but not CoS, the configuration applies only to IP traffic.
When you configure the switch to trust CoS and trust or change DSCP or precedence, then trust CoS applies to non-IP traffic and trust or change DSCP or precedence applies to IP traffic.
The cpu traffic qos dscp global configuration command configures DSCP marking for CPU-generated traffic by trusting DSCP, mutating DSCP or specifying a DSCP value. A new configuration overwrites the existing configuration.
The cpu traffic qos dscp and cpu traffic qos precedence global configuration commands are mutually exclusive. A new configuration overwrites the existing configuration.
Examples
This example shows how to configure the DSCP value of CPU-generated packets:
Switch(config)# cpu traffic qos dscp 36This example shows how to configure the switch to trust the DSCP value of incoming CPU-generated packets:
Switch(config)# cpu traffic qos dscp trustThis example shows how to mark the DSCP of CPU-generated IP traffic (including IP-SLA and TWAMP) based on the DSCP value in the packet.
The example has these results:
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Maps:
Switch(config)# mls qosSwitch(config)# mls qos map dscp-mutation mapname 0 to 30Switch(config)# mls qos map dscp-mutation mapname 34 36 38 to 48CPU QoS:
Switch(config)# cpu traffic qos dscp dscp-mutation mapnameRelated Commands
cpu traffic qos precedence
Use the cpu traffic qos precedence command in global configuration mode to configure quality of service (QoS) marking for control plane traffic. To return to the default value, use the no form of this command.
cpu traffic qos precedence {precedence-value | trust | precedence-mutation mutation-map-name}
no cpu traffic qos precedence {precedence-value | trust | precedence-mutation mutation-map-name}
Syntax Description
Command Default
Control plane (CPU) traffic is not marked for QoS.
Command Modes
Global configuration
Command History
Usage Guidelines
This feature must be configured globally for a switch; it cannot be configured per-port or per-protocol.
Enter each cpu traffic qos marking action on a separate line.
The trust keyword configures the switch to trust the incoming CoS, DSCP, or precedence value and mark the packet according to the global map configuration.
The mutation keyword configures the switch to change the incoming value according to the global mutation-map configuration.
When you configure the switch to trust CoS, the configuration applies to both IP and non-IP traffic.
When you configure the switch to trust or change DSCP or precedence but not CoS, the configuration applies only to IP traffic.
When you configure the switch to trust CoS and trust or change DSCP or precedence, then trust CoS applies to non-IP traffic and trust or change DSCP or precedence applies to IP traffic.
The cpu traffic qos precedence global configuration command configures precedence marking for CPU-generated traffic by trusting precedence, mutating precedence or specifying a precedence value. A new configuration overwrites the existing configuration.
The cpu traffic qos dscp and cpu traffic qos precedence global configuration commands are mutually exclusive. A new configuration overwrites the existing configuration.
Examples
The following example shows how to configure a precedence value of 2 for CPU traffic:
Switch(config)# cpu traffic qos precedence 2This example shows how to configure the switch to trust the precedence value of incoming CPU-generated packets:
Switch(config)# cpu traffic qos precedence trustThis example shows how to mark the precedence of CPU-generated IP traffic (including IP-SLA and TWAMP) based on the precedence value in the packet.
The example has these results:
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Maps:
Switch(config)# mls qosSwitch(config)# mls qos map dscp-mutation mapname 0 to 24Switch(config)# mls qos map dscp-mutation mapname 16 24 32 to 48CPU QoS:
Switch(config)# cpu traffic qos precedence precedence-mutation mapnameRelated Commands
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
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
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:
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Valid values for type and interface:
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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.
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For physical interfaces:
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When you define a range, you must enter a space before the hyphen (-), for example:
gigabitethernet1/0/1 - 2
You can also enter multiple ranges. When you define multiple ranges, you must enter a space after the first entry before the comma (,). The space after the comma is optional, for example:
fastethernet1/0/3 , gigabitethernet1/0/1 - 2
fastethernet1/0/3 -4, gigabitethernet1/0/1 - 2
Examples
This example shows how to create a multiple-interface macro:
Switch(config)# define interface-range macro1 fastethernet1/0/1 -2, fastethernet1/0/5Related Commands
Executes a command on multiple ports at the same time.
show running-config
Displays the operating configuration. For syntax information, use this link to the Cisco IOS Release 12.2 Command Reference listing page: http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/prod_command_reference_list.html
Select the Cisco IOS Commands Master List, Release 12.2 to navigate to the command.
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
Command Modes
Privileged EXEC
Command History
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 12.2.
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-imageYou can verify that the directory was removed by entering the dir filesystem: privileged EXEC command.
Related Commands
deny (ARP access-list configuration)
Use the deny Address Resolution Protocol (ARP) access-list configuration command on the switch stack or on a standalone switch to deny an ARP packet based on matches against the DHCP bindings. Use the no form of this command to remove the specified access control entry (ACE) from the access list.
deny {[request] ip {any | host sender-ip | sender-ip sender-ip-mask} mac {any | host sender-mac | sender-mac sender-mac-mask} | response ip {any | host sender-ip | sender-ip sender-ip-mask} [{any | host target-ip | target-ip target-ip-mask}] mac {any | host sender-mac | sender-mac sender-mac-mask} [{any | host target-mac | target-mac target-mac-mask}]} [log]
no deny {[request] ip {any | host sender-ip | sender-ip sender-ip-mask} mac {any | host sender-mac | sender-mac sender-mac-mask} | response ip {any | host sender-ip | sender-ip sender-ip-mask} [{any | host target-ip | target-ip target-ip-mask}] mac {any | host sender-mac | sender-mac sender-mac-mask} [{any | host target-mac | target-mac target-mac-mask}]} [log]
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
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
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-hostsSwitch(config-arp-nacl)# deny ip host 1.1.1.1 mac host 0000.0000.abcdSwitch(config-arp-nacl)# endYou can verify your settings by entering the show arp access-list privileged EXEC command.
Related Commands
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] [routing] [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] [routing] [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] [routing] [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] [routing] [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}] [routing] [sequence value] [time-range name]
Note
Syntax Description
Note
Defaults
No IPv6 access list is defined.
Command Modes
IPv6 access list configuration
Command History
Usage Guidelines
The deny (IPv6 access-list configuration mode) command is similar to the deny (IPv4 access-list configuration mode) command, but 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 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 somewhere other than at the end of the list, create a new statement with an appropriate entry number between two existing entry numbers to show where it belongs.
Note
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 its source; the destination prefix filters traffic based upon its destination.)
The switch supports IPv6 address matching for a full range of prefix lengths.
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:
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 prevents all packets that have a destination TCP port number greater than 5000 from leaving the interface. The second deny entry 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 permits all ICMP packets to leave the interface. The second permit entry 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 CISCOSwitch(config-ipv6-acl)# deny tcp any any gt 5000Switch config-ipv6-acl)# deny ::/0 lt 5000 ::/0 logSwitch(config-ipv6-acl)# permit icmp any anySwitch(config-ipv6-acl)# permit any anySwitch(config-ipv6-acl)# exitSwitch(config)# interface gigabitethernet0/2Switch(config-if)# no switchportSwitch(config-if)# ipv6 address 2001::/64 eui-64Switch(config-if)# ipv6 traffic-filter CISCO outRelated Commands
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
Note
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.
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
Usage Guidelines
You enter MAC-access list configuration mode by using the mac access-list extended global configuration command.
If you use the host keyword, you cannot enter an address mask; if you do not use the host keyword, you must enter an address mask.
When an access control entry (ACE) is added to an access control list, an implied deny-any-any condition exists at the end of the list. That is, if there are no matches, the packets are denied. However, before the first ACE is added, the list permits all packets.
Note
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 0You can verify your settings by entering the show access-lists privileged EXEC command.
Related Commands
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
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 terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# interface gigabitethernet1/0/3Switch(config-if)# dot1x auth-fail max-attempts 2Switch(config-if)# endSwitch(config)# endSwitch#You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
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 vlan-id
Syntax Description
Defaults
No restricted VLAN is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
You can configure a restricted VLAN on ports configured as follows:
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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:
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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 terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# interface gigabitethernet1/0/1Switch(config-if)# dot1x auth-fail vlan 40Switch(config-if)# endSwitch(config)# endSwitch#You can verify your configuration by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
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 default
Use the dot1x default interface configuration command to reset the configurable 802.1x parameters to their default values.
dot1x default
Syntax Description
This command has no arguments or keywords.
Defaults
These are the default values:
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Command Modes
Interface configuration
Command History
Examples
This example shows how to reset the configurable 802.1x parameters:
Switch(config-if)# dot1x defaultYou can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
show dot1x [interface interface-id]
Displays 802.1x status for the specified port.
dot1x guest-vlan
Use the dot1x guest-vlan interface configuration command to specify an active VLAN as an 802.1x guest VLAN. Use the no form of this command to return to the default setting.
dot1x guest-vlan vlan-id
no dot1x guest-vlan
Syntax Description
Defaults
No guest VLAN is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
When you configure a guest VLAN, clients that are not 802.1x-capable are put into the guest VLAN when the server does not receive a response to its Extensible Authentication Protocol over LAN (EAPOL) request/identity frame. Clients that are 802.1x-capable but fail authentication are not granted access to the network.
Guest VLANs are supported on 802.1x ports in single-host mode and multiple-hosts mode.
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 is returned to the unauthorized state, and authentication is restarted. The EAPOL history is reset upon loss of link.
Entering the dot1x guest-vlan supplicant global configuration command disables this behavior.
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 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 RSPAN VLAN or a voice VLAN as an 802.1x guest VLAN. The guest VLAN feature is not supported on internal VLANs (routed ports) or trunk ports; it is supported only on access ports.
Examples
This example shows how to specify VLAN 5 as an 802.1x guest VLAN:
Switch(config-if)# dot1x guest-vlan 5You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
show dot1x [interface interface-id]
Displays 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 802.1x-authorized port that has the dot1x port-control interface configuration command set to auto. Use the no form of this command to return to the default setting.
dot1x host-mode {multi-host | single-host}
no dot1x host-mode [multi-host | single-host]
Syntax Description
multi-host
Enable multiple-hosts mode on the switch.
single-host
Enable single-host mode on the switch.
Note
Command Default
The default is single-host mode.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to limit an 802.1x-enabled port to a single client or to attach multiple clients to an 802.1x-enabled port. In multiple-hosts mode, only one of the attached hosts must be successfully authorized for all hosts to be granted network access. If the port becomes unauthorized (re-authentication fails or an Extensible Authentication Protocol over LAN [EAPOL]-logoff message is received), all attached clients are denied access to the network.
Before entering this command, make sure that the dot1x port-control interface configuration command is set to auto for the specified port.
The dot1x host-mode multi-domain interface configuration command is not supported on the switch. Configuring this command on an interface causes the interface to go into the error-disabled state.
Examples
This example shows how to enable 802.1x globally, enable 802.1x on a port, and enable multiple-hosts mode:
Switch(config)# dot1x system-auth-controlSwitch(config)# interface gigabitethernet1/0/1Switch(config-if)# dot1x port-control autoSwitch(config-if)# dot1x host-mode multi-hostYou can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
show dot1x [interface interface-id]
Displays 802.1x status for the specified port.
dot1x initialize
Use the dot1x initialize privileged EXEC command to manually return the specified 802.1x-enabled port to an unauthorized state before initiating a new authentication session on the port.
dot1x initialize interface interface-id
Syntax Description
Defaults
There is no default setting.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use this command to initialize the 802.1x state machines and to set up a fresh environment for authentication. After you enter this command, the port status becomes unauthorized.
There is no no form of this command.
Examples
This example shows how to manually initialize a port:
Switch# dot1x initialize interface gigabitethernet1/0/2You can verify the unauthorized port status by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
show dot1x [interface interface-id]
Displays 802.1x status for the specified port.
dot1x max-reauth-req
Use the dot1x max-reauth-req interface configuration command to set the maximum number of times that the switch restarts the authentication process before a port transitions to the unauthorized state. Use the no form of this command to return to the default setting.
dot1x max-reauth-req count
no dot1x max-reauth-req
Syntax Description
count
Number of times that the switch restarts the authentication process before the port transitions to the unauthorized state. The range is 1 to 10.
Defaults
The default is 2 times.
Command Modes
Interface configuration
Command History
Usage Guidelines
You should change the default value of this command only to adjust for unusual circumstances such as unreliable links or specific behavioral problems with certain clients and authentication servers.
Examples
This example shows how to set 4 as the number of times that the switch restarts the authentication process before the port transitions to the unauthorized state:
Switch(config-if)# dot1x max-reauth-req 4You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
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 test eapol-capable tx-period
Sets the number of seconds that the switch waits for a response to an EAP-request/identity frame from the client before resending the request.
show dot1x [interface interface-id]
Displays 802.1x status for the specified port.
dot1x max-req
Use the dot1x max-req interface configuration command to set the maximum number of times that the switch retransmits 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 retransmits 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
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 before restarting the authentication process:
Switch(config-if)# dot1x max-req 5You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
dot1x test eapol-capable tx-period
Sets the number of seconds that the switch waits for a response to an EAP-request/identity frame from the client before resending the request.
show dot1x [interface interface-id]
Displays 802.1x status for the specified port.
dot1x 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
Defaults
The default is force-authorized.
Command Modes
Interface configuration
Command History
Usage Guidelines
You must globally enable 802.1x on the switch by using the dot1x system-auth-control global configuration command before enabling 802.1x on a specific port.
The 802.1x protocol is supported on Layer 2 static-access ports, voice VLAN ports, and Layer 3 routed ports.
You can use the auto keyword only if the port is not configured as one of these:
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To globally disable 802.1x on the switch, use the no dot1x system-auth-control global configuration command. To disable 802.1x on a specific port, use the no dot1x port-control interface configuration command.
Examples
This example shows how to enable 802.1x on a port:
Switch(config)# interface fastethernet1/0/1Switch(config-if)# dot1x port-control autoYou can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
show dot1x [interface interface-id]
Displays 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 802.1x-enabled port.
dot1x re-authenticate interface interface-id
Syntax Description
Defaults
There is no default setting.
Command Modes
Privileged EXEC
Command History
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 fastethernet1/0/1dot1x 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
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 reauthenticationThis 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 reauthenticationSwitch(config-if)# dot1x timeout reauth-period 4000You can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
dot1x test eapol-capable reauth-period
Sets the number of seconds between re-authentication attempts.
show dot1x [interface interface-id]
Displays 802.1x status for the specified port.
dot1x supplicant force-multicast
Use the dot1x supplicant force-multicast global configuration command to force a supplicant switch to send only multicast Extensible Authentication Protocol over LAN (EAPOL) packets whenever it receives multicast or unicast EAPOL packets. Use the no form of this command to return to the default setting.
dot1x supplicant force-multicast
no dot1x supplicant force-multicast
Syntax Description
This command has no arguments or keywords.
Defaults
The supplicant switch sends unicast EAPoL packets when it receives unicast EAPOL packets. Similarly, it sends multicast EAPOL packets when it receives multicast EAPOL packets.
Command Modes
Global configuration
Command History
Usage Guidelines
Enable this command on the supplicant switch for Network Edge Access Topology (NEAT) to work in all host modes.
Examples
This example shows how force a supplicant switch to send multicast EAPOL packets to authenticator switch:
Switch(config)# dot1x supplicant force-multicastRelated Commands
dot1x system-auth-control
Use the dot1x system-auth-control global configuration command to globally enable 802.1x. Use the no form of this command to return to the default setting.
dot1x system-auth-control
no dot1x system-auth-control
Syntax Description
This command has no arguments or keywords.
Defaults
802.1x is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
You must enable authentication, authorization, and accounting (AAA) and specify the authentication method list before globally enabling 802.1x. A method list describes the sequence and authentication methods to be queried to authenticate a user.
Examples
This example shows how to globally enable 802.1x on a switch:
Switch(config)# dot1x system-auth-controlYou can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
Enables manual control of the authorization state of the port.
show dot1x [interface interface-id]
Displays 802.1x status for the specified port.
dot1x test eapol-capable
Use the dot1x test eapol-capable privileged EXEC command to monitor IEEE 802.1x activity on all the switch ports and to display information about the devices that are connected to the ports that support IEEE 802.1x.
dot1x test eapol-capable [interface interface-id]
Syntax Description
Defaults
There is no default setting.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Use this command to test the IEEE 802.1x capability of the devices connected to all ports or to specific ports on a switch.
There is not a no form of this command.
Examples
This example shows how to enable the IEEE 802.1x readiness check on a switch to query a port. It also shows the response received from the queried port verifying that the device connected to it is IEEE 802.1x-capable:
switch# dot1x test eapol-capable interface gigabitethernet1/0/13DOT1X_PORT_EAPOL_CAPABLE:DOT1X: MAC 00-01-02-4b-f1-a3 on gigabitethernet1/0/13 is EAPOL capableRelated Commands
dot1x test timeout timeout
Configures the timeout used to wait for EAPOL response to an IEEE 802.1x readiness query.
dot1x test timeout
Use the dot1x test timeout global configuration command to configure the timeout used to wait for EAPOL response from a port being queried for IEEE 802.1x readiness.
dot1x test timeout timeout
Syntax Description
Defaults
The default setting is 10 seconds.
Command Modes
Global configuration
Command History
Usage Guidelines
Use this command to configure the timeout used to wait for EAPOL response.
There is not a no form of this command.
Examples
This example shows how to configure the switch to wait 27 seconds for an EAPOL response:
Switch# dot1x test timeout 27You can verify the timeout configuration status by entering the show run privileged EXEC command.
Related Commands
dot1x test eapol-capable [interface interface-id]
Checks for IEEE 802.1x readiness on devices connected to all or to specified IEEE 802.1x-capable ports.
dot1x timeout
Use the dot1x timeout interface configuration command to set 802.1x timers. Use the no form of this command to return to the default setting.
dot1x timeout {quiet-period seconds | reauth-period seconds | server-timeout seconds | supp-timeout seconds | tx-period seconds}
no dot1x timeout {quiet-period | reauth-period | server-timeout | supp-timeout | tx-period}
Syntax Description
Defaults
These are the default settings:
reauth-period is 3600 seconds.
quiet-period is 60 seconds.
tx-period is 30 seconds.
supp-timeout is 30 seconds.
server-timeout is 30 seconds.
Command Modes
Interface configuration
Command History
12.1(14)AX
This command was introduced.
12.2(40)SE
The range for tx-period seconds is incorrect. The correct range is from 1 to 65535.
Usage Guidelines
You should change the default value of this command only to adjust for unusual circumstances such as unreliable links or specific behavioral problems with certain clients and authentication servers.
The dot1x timeout reauth-period interface configuration command affects the behavior of the switch only if you have enabled periodic re-authentication by using the dot1x reauthentication interface configuration command.
During the quiet period, the switch does not accept or initiate any authentication requests. If you want to provide a faster response time to the user, enter a smaller number than the default.
Examples
This example shows how to enable periodic re-authentication and to set 4000 as the number of seconds between re-authentication attempts:
Switch(config-if)# dot1x reauthenticationSwitch(config-if)# dot1x timeout reauth-period 4000This example shows how to set 30 seconds as the quiet time on the switch:
Switch(config-if)# dot1x timeout quiet-period 30This example shows how to set 25 seconds as the switch-to-authentication server retransmission time:
Switch(config)# dot1x timeout server-timeout 25This example shows how to set 25 seconds as the switch-to-client retransmission time for the EAP request frame:
Switch(config-if)# dot1x timeout supp-timeout 25This 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 resending the request:
Switch(config-if)# dot1x timeout tx-period 60You can verify your settings by entering the show dot1x privileged EXEC command.
Related Commands
dot1x violation-mode
Use the dot1x violation-mode interface configuration command on the switch stack or on a standalone switch to configure the violation modes that occur when a new device connects to a port or when a new device connects to a port after the maximum number of devices are connected to that port.
dot1x violation-mode {shutdown | restrict | protect}
no dot1x violation-mode
Syntax Description
Defaults
By default dot1x violation-mode protect is enabled.
Command Modes
Interface configuration
Command History
Examples
This example shows how to configure an IEEE 802.1x-enabled port as error disabled and to shut down when a new device connects to the port:
Switch(config-if)# dot1x violation-mode shutdownThis example shows how to configure an IEEE 802.1x-enabled port to generate a system error message and change the port to restricted mode when a new device connects to the port:
Switch(config-if)# dot1x violation-mode restrictThis example shows how to configure an IEEE 802.1x-enabled port to ignore a new connected device when it is connected to the port:
Switch(config-if)# dot1x violation-mode protectYou can verify your settings by entering the show dot1x [interface interface-id] privileged EXEC command.
Related Commands
show dot1x [interface interface-id]
Displays IEEE 802.1x status for the specified port.
duplex
Use the duplex interface configuration command to specify the duplex mode of operation for Fast Ethernet and Gigabit Ethernet ports. Use the no form of this command to return the port to its default value.
duplex {auto | full | half}
no duplex
Syntax Description
Defaults
The default is auto for Fast Ethernet ports and for 1000BASE-T small form-factor pluggable (SFP) modules.
The default is full for 100BASE-FX MMF SFP modules.
Command Modes
Interface configuration
Command History
12.1(14)AX
This command was introduced.
12.2(25)EY
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.
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.
For 10/100 Mbps ports, if both speed and duplex are set to specific values, the link operates at the negotiated speed and duplex value.
For 10/100/1000 Mbps ports, if both the speed and duplex are set to specific values, autonegotiation is disabled.
Beginning with Cisco IOS Release 12.2(25)EY, you can configure the duplex setting when the speed is set to auto.
This command is not available on SFP module ports unless a 1000BASE-T SFP module or a 100BASE-FX MMF SFP module is in the port. All other SFP modules operate only in full-duplex mode.
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Note
Caution
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 a port for full duplex operation:
Switch(config)# interface fastethernet1/0/11Switch(config-if)# duplex fullYou can verify your setting by entering the show interfaces privileged EXEC command.
Related Commands
Displays the interface settings on the switch.
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 | dtp-flap | gbic-invalid | l2ptguard| link-flap | loopback | pagp-flap}
no errdisable detect cause {all | dtp-flap | gbic-invalid | l2ptguard | link-flap | loopback | pagp-flap}
Syntax Description
Note
Defaults
Detection is enabled for all causes. All causes, except for per-VLAN error disabling, are configured to shut down the entire port.
Command Modes
Global configuration
Command History
Usage Guidelines
A cause (dtp-flap, gbic-invalid, l2ptguard, link-flap, loopback, and pagp-flap) 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 link-down state.
When a port is error-disabled, it is effectively shut down, and no traffic is sent or received on the port.
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-flapYou can verify your setting by entering the show errdisable detect privileged EXEC command.
Related Commands
Displays errdisable detection information.
show interfaces status err-disabled
Displays interface status or a list of interfaces in the error-disabled state.
errdisable detect cause small-frame
Use the errdisable detect cause small-frame global configuration command on the switch stack or on a standalone switch to allow any switch port to be error disabled if incoming VLAN-tagged packets are small frames (67 bytes or less) and arrive at the minimum configured rate (the threshold). Use the no form of this command to return to the default setting.
errdisable detect cause small-frame
no errdisable detect cause small-frame
Syntax Description
This command has no arguments or keywords.
Defaults
This feature is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
This command globally enables the small-frame arrival feature. Use the small violation-rate interface configuration command to set the threshold for each port.
You can configure the port to be automatically re-enabled by using the errdisable recovery cause small-frame global configuration command. You configure the recovery time by using the errdisable recovery interval interval global configuration command.
Examples
This example shows how to enable the switch ports to be put into the error-disabled mode if incoming small frames arrive at the configured threshold:
Switch(config)# errdisable detect cause small-frameYou can verify your setting by entering the show interfaces privileged EXEC command.
Related Commands
errdisable recovery cause small-frame
Use the errdisable recovery cause small-frame global configuration command on the switch stack or on a standalone switch to enable the recovery timer for ports to be automatically re-enabled after they are error disabled by the arrival of small frames. Use the no form of this command to return to the default setting.
errdisable recovery cause small-frame
no errdisable recovery cause small-frame
Syntax Description
This command has no arguments or keywords.
Defaults
This feature is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
This command enables the recovery timer for error-disabled ports. You configure the recovery time by using the errdisable recovery interval interval interface configuration command.
Examples
This example shows how to set the recovery timer:
Switch(config)# errdisable recovery cause small-frameYou can verify your setting by entering the show interfaces user EXEC command.
Related Commands
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 | 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 | dtp-flap | gbic-invalid | l2ptguard| link-flap | loopback | pagp-flap | psecure-violation | security-violation | udld | vmps} | {interval interval}
Syntax Description
Note
Defaults
Recovery is disabled for all causes.
The default recovery interval is 300 seconds.
Command Modes
Global configuration
Command History
12.1(14)AX
This command was introduced.
12.2(25)EY
The arp-inspection keyword was added.
Usage Guidelines
A cause (bpduguard, dtp-flap, gbic-invalid, l2ptguard, link-flap, loopback, pagp-flap, psecure-violation, security-violation, udld, vmps) is defined as the reason why the error-disabled state occurred. When a cause is detected on an interface, the interface is placed in error-disabled state, an operational state similar to link-down state. If you do not enable errdisable recovery for the cause, the interface stays in error-disabled state until you enter a shutdown and no shutdown interface configuration command. If you enable the recovery for a cause, the interface is brought out of the error-disabled state and allowed to retry the operation again when all the causes have timed out.
Otherwise, you must enter the shutdown then no shutdown commands to manually recover an interface from the error-disabled state.
Examples
This example shows how to enable the recovery timer for the BPDU guard error-disable cause:
Switch(config)# errdisable recovery cause bpduguardThis example shows how to set the timer to 500 seconds:
Switch(config)# errdisable recovery interval 500You can verify your settings by entering the show errdisable recovery privileged EXEC command.
Related Commands
Displays errdisable recovery timer information.
show interfaces status err-disabled
Displays interface status or a list of interfaces in error-disabled state.
ethernet evc
Use the ethernet evc global configuration command to define an Ethernet virtual connection (EVC) and to enter EVC configuration mode. Use the no form of this command to delete the EVC.
ethernet evc evc-id
no ethernet evc evc-id
Syntax Description
Defaults
No EVCs are defined.
Command Modes
Global configuration
Command History
Usage Guidelines
After you enter the ethernet evc evc-id command, the switch enters EVC configuration mode, and these configuration commands are available:
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Examples
This example shows how to define an EVC and to enter EVC configuration mode:
Switch(config)# ethernet evc test1Switch(config-evc)#Related Commands
service instance id ethernet evc-id
Configures an Ethernet service instance and attaches an EVC to it.
Displays information about configured EVCs.
ethernet lmi
Use the ethernet lmi global configuration command to configure enable Ethernet Local Management Interface (E-LMI) and to configure the switch as a provider-edge (PE) or customer-edge (CE) device. Use the no form of this command to disable E-LMI globally or to disable E-LMI CE.
ethernet lmi {ce | global}
no ethernet lmi {ce | global}
Syntax Description
Defaults
Ethernet LMI is disabled. When enabled with the global keyword, by default the switch is a PR device.
Command Modes
Global configuration
Command History
Usage Guidelines
Use ethernet lmi global command to enable E-LMI globally. Use ethernet lmi ce command to enable the switch as E-LMI CE device.
Ethernet LMI is disabled by default on an interface and must be explicitly enabled by entering the ethernet lmi interface interface configuration command. The ethernet lmi global command enables Ethernet LMI in PE mode on all interfaces for an entire device. The benefit of this command is that you can enable Ethernet LMI on all interfaces with one command instead of enabling Ethernet LMI separately on each interface. To enable the interface in CE mode, you must also enter the ethernet lmi ce global configuration command.
To disable Ethernet LMI on a specific interface after you have entered the ethernet lmi global command, enter the no ethernet lmi interface interface configuration command.
The sequence in which you enter the ethernet lmi interface interface configuration and ethernet lmi global global configuration commands is important. The latest command entered overrides the prior command entered.
Note
http://www.cisco.com/en/US/docs/ios/cether/command/reference/ce_book.htmlTo enable the switch as an Ethernet LMI CE device, you must enter both the ethernet lmi global and ethernet lmi ce commands. By default Ethernet LMI is disabled, and, when enabled the switch is in provider-edge mode unless you also enter the ethernet lmi ce command.
When the switch is configured as an Ethernet LMI CE device, these interface configuration commands and keywords are visible, but not supported:
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Examples
This example shows how to configure the switch as an Ethernet LMI CE device:
Switch(config)# ethernet lmi globalSwitch(config)# ethernet lmi ceRelated Commands
ethernet lmi interface configuration command
Enables Ethernet LMI for a user-network interface.
ethernet lmi ce-vlan map
Use the ethernet lmi ce-vlan map Ethernet service configuration command to configure Ethernet Local Management Interface (E-LMI) parameters. Use the no form of this command to remove the configuration.
ethernet lmi ce-vlan map {vlan-id | any | default | untagged}
no ethernet lmi ce-vlan map {vlan-id | any | default | untagged}
Syntax Description
Defaults
No E-LMI mapping parameters are defined.
Command Modes
Ethernet service configuration
Command History
Usage Guidelines
Use this command to configure an E-LMI customer VLAN-to-EVC map for a particular user-network interface (UNI).
E-LMI mapping parameters are related to the bundling characteristics set by entering the ethernet uni {bundle [all-to-one] | multiplex} interface configuration command.
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Examples
This example shows how to configure an E-LMI customer VLAN-to-EVC map to map EVC test to customer VLAN 101 in service instance 333 on the interface:
Switch(config-if)# service instance 333 ethernet testSwitch(config-if-srv)# ethernet lmi ce-vlan map 101Related Commands
service instance id ethernet
Defines an Ethernet service instance and enters Ethernet service configuration mode.
Displays information about configured Ethernet service instances.
ethernet oam remote-failure
Use the ethernet oam remote-failure interface configuration or configuration template command to configure Ethernet operations, maintenance, and administration (EOM) remote failure indication. Use the no form of this command to remove the configuration.
ethernet oam remote-failure {critical-event | dying-gasp | link-fault} action error-disable-interface
no ethernet oam remote-failure {critical-event | dying-gasp | link-fault} action
Syntax Description
Defaults
Configuration template
Interface configuration
Command Modes
Ethernet service configuration
Command History
Usage Guidelines
You can apply this command to an Ethernet OAM template and to an interface. The interface configuration takes precedence over template configuration. To enter OAM template configuration mode, use the template template-name global configuration command.
You can configure an error-disable action to occur if the remote link goes down, if the remote device is disabled, or if the remote device disables Ethernet OAM on the interface.
The Catalyst 3750 Metro switch does not generate Link Fault or Critical Event OAM PDUs. However, if these PDUs are received from a link partner, they are processed. The switch supports generating and receiving Dying Gasp OAM PDUs when Ethernet OAM is disabled, the interface is shut down, the interface enters the error-disabled state, or the switch is reloading. It can respond to, but not generate, Dying Gasp PDUs based on loss of power.
For complete command and configuration information for the Ethernet OAM protocol, see the Cisco IOS Carrier Ethernet Configuration Guide at this URL:
http://www.cisco.com/en/US/docs/ios/cether/configuration/guide/12_2sr/ce_12_2sr_book.htmlFor information about other CFM and Ethernet OAM commands, see the Cisco IOS Carrier Ethernet Command Reference at this URL:
http://www.cisco.com/en/US/docs/ios/cether/command/reference/ce_book.htmlExamples
This example shows how to configure an Ethernet OAM template for remote-failure indication when an unrecoverable error has occurred and how to apply it to an interface:
Switch(config)# template oam1Switch(config-template)# ethernet oam remote-failure dying-gasp action error-disable interfaceSwitch(config-template)# exitSwitch(config)# interface gigabitethernet 0/1Switch(config-if)# source template oam1Switch(config-if)# exitThis example shows how to configure an Ethernet OAM remote-failure indication on one interface for unrecoverable errors:
Switch(config)# interface gigabitethernet 0/1Switch(config-if)# ethernet oam remote-failure dying-gasp action error-disable interfaceSwitch(config-if)# exitRelated Commands
show ethernet oam status [interface interface-id]
Displays configured Ethernet OAM remote failure conditions on all interfaces or on the specified interface.
ethernet uni
Use the ethernet uni interface configuration command to set UNI bundling attributes. Use the no form of this command to return to the default bundling configuration.
ethernet uni {bundle [all-to-one] | multiplex}
no ethernet uni {bundle | multiplex}
Syntax Description
Defaults
If bundling or multiplexing attributes are not configured, the default is bundling with multiplexing. The UNI then has one or more EVCs with one or more CE VLANs mapped to each EVC.
Command Modes
Interface configuration
Command History
Usage Guidelines
The UNI attributes determine the functionality that the interface has regarding bundling VLANs, multiplexing EVCs, and the combination of these.
If you want both bundling and multiplexing services for a UNI, you do not need to configure bundling or multiplexing. If you want only bundling, or only multiplexing, you need to configure it appropriately.
When you configure, change, or remove a UNI service type, the EVC and CE-VLAN ID configurations are checked to ensure that the configurations and the UNI service types match. If the configurations do not match, the command is rejected.
If you intend to use the ethernet lmi ce-vlan map any service configuration command, you must first configure all-to-one bundling on the interface. See the ethernet lmi ce-vlan map section for more information.
Examples
This example shows how to configure bundling without multiplexing:
Switch(config-if)# ethernet uni bundleTo verify UNI service type, enter the show ethernet service interface detail privileged EXEC command.
Related Commands
Displays information about Ethernet service instances on an interface, including service type.
ethernet uni id
Use the ethernet uni interface configuration command to create an Ethernet user-network interface (UNI) ID. Use the no form of this command to remove the UNI ID.
ethernet uni id name
no ethernet uni id
Syntax Description
name
Identify an Ethernet UNI ID. The name should be unique for all UNIs that are part of a given service instance and can be up to 64 characters in length.
Defaults
No UNI IDs are created.
Command Modes
Interface configuration
Command History
Usage Guidelines
When you configure a UNI ID on a port, that ID is used as the default name for all maintenance end points (MEPs) configured on the port.
You must enter the ethernet uni id name command on all ports that are directly connected to customer-edge (CE) devices. If the specified ID is not unique on the device, an error message appears.
Examples
This example shows how to identify a unique UNI:
Switch(config-if)# ethernet uni id test2Related Commands
Displays information about Ethernet service instances on an interface, including service type.
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
Syntax Description
Defaults
The default is flowcontrol receive off.
Command Modes
Interface configuration
Command History
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:
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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.
Examples
This example shows how to configure the local port to not support flow control by the remote port:
Switch(config-if)# flowcontrol receive offYou can verify your settings by entering the show interfaces privileged EXEC command.
Related Commands
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
Defaults
No port-channel logical interfaces are defined.
Command Modes
Global configuration
Command History
Usage Guidelines
For Layer 2 EtherChannels, you do not have to create a port-channel 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 when the channel group gets its first physical port. If you create the port-channel 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
Caution
Follow these guidelines when you use the interface port-channel command:
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For a complete list of configuration guidelines, see the "Configuring EtherChannels" chapter in the software guide for this release.
Examples
This example shows how to create port-channel 5:
Switch(config)# interface port-channel 5You can verify your setting by entering the show running-config privileged EXEC or show etherchannel channel-group-number detail privileged EXEC command.
Related Commands
Assigns an Ethernet port to an EtherChannel group.
Displays EtherChannel information for a channel.
show running-config
Displays the operating configuration. For syntax information, use this link to the Cisco IOS Release 12.2 Command Reference listing page: http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/prod_command_reference_list.html
Select the Cisco IOS Commands Master List, Release 12.2 to navigate to the command.
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
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:
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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:
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For physical interfaces:
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When you define a range, you must enter a space between the first entry and the hyphen (-):
interface range gigabitethernet1/0/1 -2When you define multiple ranges, you must still enter a space after the first entry, before the comma (,):
interface range fastethernet1/0/3 , gigabitethernet1/0/1 - 2interface range fastethernet1/0/3 -5, fastethernet1/0/7 -8You cannot specify both a macro and an interface range in the same command.
A single interface can also be specified in port-range (this would make the command similar to the interface interface-id global configuration command).
Note
Examples
This example shows how to use the interface range command to enter interface range configuration mode to apply commands to two ports:
Switch(config)# interface range gigabitethernet1/0/1 - 2Switch(config-if-range)#This example shows how to use a port-range macro macro1 for the same function. The advantage is that you can reuse macro1 until you delete it.
Switch(config)# define interface-range macro1 gigabitethernet1/0/1 - 2Switch(config)# interface range macro macro1Switch(config-if-range)#Related Commands
Creates an interface range macro.
show running-config
Displays the operating configuration. For syntax information, use this link to the Cisco IOS Release 12.2 Command Reference listing page: http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/prod_command_reference_list.html
Select the Cisco IOS Commands Master List, Release 12.2 to navigate to the command.
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
Defaults
The default VLAN interface is VLAN 1.
Command Modes
Global configuration
Command History
Usage Guidelines
You cannot delete the VLAN 1 interface.
SVIs are created the first time that you enter the interface vlan vlan-id command for a particular VLAN. The vlan-id corresponds to the VLAN-tag associated with data frames on an ISL or 802.1Q encapsulated trunk or the VLAN ID configured for an access port.
Note
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.
You can reinstate a deleted SVI by entering the interface vlan vlan-id command for the deleted interface. The interface comes back up, but much of the previous configuration will be gone.
The interrelationship between the number of SVIs configured on a switch and the number of other features being configured might have an impact on CPU utilization due to hardware limitations. You can use the sdm prefer global configuration command to reallocate system hardware resources based on templates and feature tables. For more information, see the sdm prefer command.
Examples
This example shows how to create a new SVI with VLAN ID 23 and enter interface configuration mode:
Switch(config)# interface vlan 23Switch(config-if)#You can verify your setting by entering the show interfaces and show interfaces vlan vlan-id privileged EXEC commands.
Related Commands
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
Defaults
No access list is applied to the interface.
Command Modes
Interface configuration
Command History
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):
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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.
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You can apply IP ACLs to both outbound or inbound Layer 3 interfaces.
A Layer 3 interface can have one IP ACL applied in each direction.
You can configure only one VLAN map and one router ACL in each direction (input/output) on a VLAN interface.
For standard inbound access lists, after the switch receives a packet, it checks the source address of the packet against the access list. IP extended access lists can optionally check other fields in the packet, such as the destination IP address, protocol type, or port numbers. If the access list permits the packet, the switch continues to process the packet. If the access list denies the packet, the switch discards the packet. If the access list has been applied to a Layer 3 interface, discarding a packet (by default) causes the generation of an Internet Control Message Protocol (ICMP) Host Unreachable message. ICMP Host Unreachable messages are not generated for packets discarded on a Layer 2 interface.
For standard outbound access lists, after receiving a packet and sending it to a controlled interface, the switch checks the packet against the access list. If the access list permits the packet, the switch sends the packet. If the access list denies the packet, the switch discards the packet and, by default, generates an ICMP Host Unreachable message.
If the specified access list does not exist, all packets are passed.
Examples
This example shows how to apply IP access list 101 to inbound packets on a port:
Switch(config)# interface gigabitethernet1/0/1Switch(config-if)# ip access-group 101 inYou can verify your settings by entering the show ip interface, show access-lists, or show ip access-lists privileged EXEC command.
Related 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
Defaults
No IP address is defined.
Command Modes
Interface configuration
Command History
Usage Guidelines
If you remove the switch IP address through a Telnet session, your connection to the switch will be lost.
Hosts can determine 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
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 DHCP server and you remove the switch IP address by using the no ip address command, IP processing is disabled, and the BOOTP or 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 1Switch(config-if)# ip address 172.20.128.2 255.255.255.0This example shows how to configure the IP address for a port on the Layer 3 switch:
Switch(config)# ip multicast-routingSwitch(config)# interface gigabitethernet1/0/1Switch(config-if)# no switchportSwitch(config-if)# ip address 172.20.128.2 255.255.255.0You can verify your settings by entering the show running-config privileged EXEC command.
Related Commands
show running-config
Displays the operating configuration. For syntax information, use this link to the Cisco IOS Release 12.2 Command Reference listing page: http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/prod_command_reference_list.html
Select the Cisco IOS Commands Master List, Release 12.2 to navigate to the command.
ip arp inspection filter vlan
Use the ip arp inspection filter vlan global configuration command on the switch stack or on a standalone switch to permit or deny Address Resolution Protocol (ARP) requests and responses from a host configured with a static IP address when dynamic ARP inspection is enabled. Use the no form of this command to return to the default settings.
ip arp inspection filter arp-acl-name vlan vlan-range [static]
no ip arp inspection filter arp-acl-name vlan vlan-range [static]
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
Defaults
No defined ARP ACLs are applied to any VLAN.
Command Modes
Global configuration
Command History
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 1You can verify your settings by entering the show ip arp inspection vlan 1 privileged EXEC command.
Related Commands
Defines an ARP ACL.
Denies an ARP packet based on matches against the DHCP bindings.
Permits an ARP packet based on matches against the DHCP bindings.
Displays detailed information about ARP access lists.
show ip arp inspection vlan vlan-range
Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.
ip arp inspection limit
Use the ip arp inspection limit interface configuration command on the switch stack or on a standalone switch to limit the rate of incoming Address Resolution Protocol (ARP) requests and responses on an interface. It prevents dynamic ARP inspection from using all of the switch resources if a denial-of-service attack occurs. Use the no form of this command to return to the default settings.
ip arp inspection limit {rate pps [burst interval seconds] | none}
no ip arp inspection limit
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
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
Usage Guidelines
The rate applies to both trusted and untrusted interfaces. Configure appropriate rates on trunks to process packets across multiple dynamic ARP inspection-enabled VLANs, or use the none keyword to make the rate unlimited.
After a switch receives more than the configured rate of packets every second consecutively over a number of burst seconds, the interface is placed into an error-disabled state.
Unless you explicitly configure a rate limit on an interface, changing the trust state of the interface also changes its rate limit to the default value for that trust state. After you configure the rate limit, the interface retains the rate limit even when its trust state is changed. If you enter the no ip arp inspection limit interface configuration command, the interface reverts to its default rate limit.
You should configure trunk ports with higher rates to reflect their aggregation. When the rate of incoming packets exceeds the user-configured rate, the switch places the interface into an error-disabled state. The error-disable recovery feature automatically removes the port from the error-disabled state according to the recovery setting.
The rate of incoming ARP packets on EtherChannel ports equals the sum of the incoming rate of ARP packets from all channel members. Configure the rate limit for EtherChannel ports only after examining the rate of incoming ARP packets on all the channel members.
Examples
This example shows how to limit the rate of incoming ARP requests on a port to 25 pps and to set the interface monitoring interval to 5 consecutive seconds:
Switch(config)# interface gigabitethernet1/0/1Switch(config-if)# ip arp inspection limit rate 25 burst interval 5You can verify your settings by entering the show ip arp inspection interfaces interface-id privileged EXEC command.
Related Commands
show ip arp inspection interfaces
Displays the trust state and the rate limit of ARP packets for the specified interface or all interfaces.
ip arp inspection log-buffer
Use the ip arp inspection log-buffer global configuration command on the switch stack or on a standalone switch to configure the dynamic Address Resolution Protocol (ARP) inspection logging buffer. Use the no form of this command to return to the default settings.
ip arp inspection log-buffer {entries number | logs number interval seconds}
no ip arp inspection log-buffer {entries | logs}
Syntax Description
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
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 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 45This 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 4You can verify your settings by entering the show ip arp inspection log privileged EXEC command.
Related Commands
ip arp inspection trust
Use the ip arp inspection trust interface configuration command on the switch stack or on a standalone switch to configure an interface trust state that determines which incoming Address Resolution Protocol (ARP) packets are inspected. Use the no form of this command to return to the default setting.
ip arp inspection trust
no ip arp inspection trust
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
This command has no arguments or keywords.
Defaults
The interface is untrusted.
Command Modes
Interface configuration
Command History
Usage Guidelines
The switch does not check ARP packets that it receives on the trusted interface; it simply forwards the packets.
For untrusted interfaces, the switch intercepts all ARP requests and responses. It verifies that the intercepted packets have valid IP-to-MAC address bindings before updating the local cache and before forwarding the packet to the appropriate destination. The switch drops invalid packets and logs them in the log buffer according to the logging configuration specified with the ip arp inspection vlan logging global configuration command.
Examples
This example shows how to configure a port to be trusted:
Switch(config)# interface gigabitethernet1/0/1Switch(config-if)# ip arp inspection trustYou can verify your setting by entering the show ip arp inspection interfaces interface-id privileged EXEC command.
Related Commands
Configures the dynamic ARP inspection logging buffer.
show ip arp inspection interfaces
Displays the trust state and the rate limit of ARP packets for the specified interface or all interfaces.
Displays the configuration and contents of the dynamic ARP inspection log buffer.
ip arp inspection validate
Use the ip arp inspection validate global configuration command on the switch stack or on a standalone switch to perform specific checks for dynamic Address Resolution Protocol (ARP) inspection. Use the no form of this command to return to the default settings.
ip arp inspection validate {[src-mac] [dst-mac] [ip [allow zeros]]}
no ip arp inspection validate [src-mac] [dst-mac] [ip [allow zeros]]
Syntax Description
Defaults
No checks are performed.
Command Modes
Global configuration
Command History
12.2(25)EY
This command was introduced.
12.2(37)SE
The allow-zero keyword was added.
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.
The allow-zeros keyword interacts with ARP access control lists (ACLs) in this way:
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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-macYou can verify your setting by entering the show ip arp inspection vlan vlan-range privileged EXEC command.
Related Commands
show ip arp inspection vlan vlan-range
Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.
ip arp inspection vlan
Use the ip arp inspection vlan global configuration command on the switch stack or on a standalone switch to enable dynamic Address Resolution Protocol (ARP) inspection on a per-VLAN basis. Use the no form of this command to return to the default setting.
ip arp inspection vlan vlan-range
no ip arp inspection vlan vlan-range
This command is available only if your switch is running the enhanced multilayer image (EMI).
Syntax Description
vlan-range
VLAN number or range.
You can specify a single VLAN identified by VLAN ID number, a range of VLANs separated by a hyphen, or a series of VLANs separated by a comma. The range is 1 to 4094.
Defaults
ARP inspection is disabled on all VLANs.
Command Modes
Global configuration
Command History
Usage Guidelines
You must specify the VLANs on which to enable dynamic ARP inspection.
Dynamic ARP inspection is supported on access ports, trunk ports, EtherChannel ports, and private VLAN ports.
Examples
This example shows how to enable dynamic ARP inspection on VLAN 1:
Switch(config)# ip arp inspection vlan 1You can verify your setting by entering the show ip arp inspection vlan vlan-range privileged EXEC command.
Related Commands
Defines an ARP access control list (ACL).
show ip arp inspection vlan vlan-range
Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.
ip arp inspection vlan logging
Use the ip arp inspection vlan logging global configuration command on the switch stack or on a standalone switch to control the type of packets that are logged per VLAN. Use the no form of this command to disable this logging control.
ip arp inspection vlan vlan-range logging {acl-match {matchlog | none} | dhcp-bindings {all | none | permit} | arp-probe}
no ip arp inspection vlan vlan-range logging {acl-match | dhcp-bindings | arp-probe}
Syntax Description
Defaults
All denied or all dropped packets are logged. ARP probe packets are not logged.
Command Modes
Global configuration
Command History
12.2(25)EY
This command was introduced.
12.2(37)SE
The arp-probe keyword was added.
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:
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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 test1Switch(config-arp-nacl)# permit request ip any mac any logSwitch(config-arp-nacl)# permit response ip any any mac any any logSwitch(config-arp-nacl)# exitSwitch(config)# ip arp inspection vlan 1 logging acl-match matchlogYou can verify your settings by entering the show ip arp inspection vlan vlan-range privileged EXEC command.
Related Commands
Defines an ARP ACL.
Clears the dynamic ARP inspection log buffer.
Configures the dynamic ARP inspection logging buffer.
Displays the configuration and contents of the dynamic ARP inspection log buffer.
show ip arp inspection vlan vlan-range
Displays the configuration and the operating state of dynamic ARP inspection for the specified VLAN.
ip device tracking
To enable IP device tracking, use the ip device tracking global configuration command. Use the no form of this command to disable this feature.
ip device tracking
no ip device tracking
Syntax Description
This command has no arguments or keywords.
Command Default
IP device tracking is disabled.
Command Modes
Global configuration
Command History
Usage Guidelines
When IP device tracking is enabled, you can set the IP device tracking probe interval, count, and configure the ARP probe address with the ip device tracking probe command.
Use the show ip device tracking all command to display information about entries in the IP device tracking table. For more information about this command, see the Cisco IOS Security Command Reference, Release 12.4T.
Examples
This example shows how to enable device tracking:
Switch(config)# ip device trackingSwitch(config)#Related Commands
Configures the IP device tracking table for ARP probes.
show ip device tracking all
Displays information about the entries in the IP device tracking table.
ip device tracking maximum
Use the ip device tracking maximum command to enable IP port security binding tracking on a Layer 2 port. Use the no form of this command to disable IP port security on untrusted Layer 2 interfaces.
ip device tracking maximum {number}
no ip device tracking maximum {number}
Syntax Description
number
Specify the number of bindings created in the IP device tracking table for a port. valid values are from 0 to 2048.
Defaults
This command has no default setting.
Command Modes
Interface configuration mode
Command History
Examples
This example shows how to enable IP port security with IP-MAC filters on a Layer 2 access port:
Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# ip device trackingSwitch(config)# interface gigabitethernet1/0/3Switch(config-if)# switchport mode accessSwitch(config-if)# switchport access vlan 1Switch(config-if)# ip device tracking maximum 5Switch(config-if)# switchport port-securitySwitch(config-if)# switchport port-security maximum 5Switch(config-if)# ip verify source tracking port-securitySwitch(config-if)# endYou can verify your settings by entering the show ip verify source privileged EXEC command.
Related Commands
Enables IP source guard on untrusted Layer 2 interfaces.
Displays the IP source guard configuration and filters on a particular interface.
ip device tracking probe
Use the ip device tracking probe global configuration command to configure the IP device tracking table for Address Resolution Protocol (ARP) probes. Use the no form of this command to disable ARP probes.
ip device tracking probe {count | interval | use-svi}
no ip device tracking probe {count | interval | use-svi}
Syntax Description
Command Default
The count number is 3.
The interval is 30 seconds.
The ARP probe default source IP address is the Layer 3 interface and 0.0.0.0 for switchports.
Command Modes
Global configuration
Command History
12.2(52)SE
This command was introduced.
12.2(55)SE
The use-svi keyword was added.
Usage Guidelines
Use the count keyword option to set the number of times that the switch sends the ARP probe. The range is from 1 to 255.
Use the interval keyword option to set the number of seconds that the switch waits for a response before resending the ARP probe. The range is from 30 to 1814400 seconds.
Use the use-svi keyword option to configure the IP device tracking table to use the SVI IP address for ARP probes in cases when the default source ip address 0.0.0.0 for switch ports is used and the ARP probes drop.
Use the show ip device tracking all command to display information about entries in the IP device tracking table. For more information about this command, see the Cisco IOS Security Command Reference, Release 12.4T.
Examples
This example shows how to set SVI as the source for ARP probes:
Switch(config)# ip device tracking probe use-sviSwitch(config)#Related Commands
show ip device tracking all
Displays information about the entries in the IP device tracking table.
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
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 snoopingYou can verify your settings by entering the show ip dhcp snooping privileged EXEC command.
Related Commands
Enables DHCP snooping on a VLAN.
Displays the DHCP snooping configuration.
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
Syntax Description
Defaults
No default database is defined.
Command Modes
Privileged EXEC
Command History
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 512 bindings.
Use the show ip dhcp snooping binding privileged EXEC command to display only the dynamically configured bindings. Use the show ip source binding privileged EXEC command to display the dynamically and statically configured bindings.
Examples
This example shows how to generate a DHCP binding configuration with an expiration time of 1000 seconds on a port in VLAN 1:
Switch# ip dhcp snooping binding 0001.1234.1234 vlan 1 172.20.50.5 interface gigabitethernet1/0/1 expiry 1000You can verify your settings by entering the show ip dhcp snooping binding or the show ip dhcp source binding privileged EXEC command.
Related Commands
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 | rcp://user@host/filename | tftp://host/filename} | timeout seconds | write-delay seconds}
no ip dhcp snooping database [timeout | write-delay]
Syntax Description
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
Usage Guidelines
The DHCP snooping binding database can have up to 512 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:
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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 capacity, we recommend that you store a binding file on a TFTP server. You must create an empty file at the configured URL on network-based URLs (such as TFTP and FTP) before the switch can write bindings to the binding file at that URL for the first time.
Use the ip dhcp snooping database flash:/filename command to save the DHCP snooping binding database in the stack master NVRAM. The database is not saved in a stack member NVRAM.
Use the no ip dhcp snooping database command to 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/fileThis example shows how to store a binding file called file01.txt in the stack master NVRAM.
Switch(config)# ip dhcp snooping database flash:file01.txtYou can verify your settings by entering the show ip dhcp snooping database privileged EXEC command.
Related Commands
Enables DHCP snooping on a VLAN.
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 insertion is enabled.
Command Modes
Global configuration
Command History
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 optionYou can verify your settings by entering the show ip dhcp snooping privileged EXEC command.
Related Commands
Displays the DHCP snooping configuration.
Displays the DHCP snooping binding information.
ip dhcp snooping information option allowed-untrusted
Use the ip dhcp snooping information option allowed-untrusted global configuration command on an aggregation switch to configure it to accept DHCP packets with option-82 information that are received on untrusted ports that might be connected to an edge switch. Use the no form of this command to configure the switch to drop these packets from the edge switch.
ip dhcp snooping information option allowed-untrusted
no ip dhcp snooping information option allowed-untrusted
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
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 allowed-untrusted command on the aggregation switch. The aggregation switch can learn the bindings for a host even though the aggregation switch receives DHCP snooping packets on an untrusted 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
Examples
This example shows how to configure an access switch to not check the option-82 information in untrusted packets from an edge switch and to accept the packets:
Switch(config)# ip dhcp snooping information option allowed-untrustedYou can verify your settings by entering the show ip dhcp snooping privileged EXEC command.
Related Commands
Displays the DHCP snooping configuration.
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
string ASCII-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
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
Examples
This example shows how to configure the option- 82 remote-ID suboption:
Switch(config)# ip dhcp snooping information option format remote-id hostnameYou can verify your settings by entering the show ip dhcp snooping user EXEC command.
Related Commands
ip dhcp snooping vlan information option format-type circuit-id string
Configures the option-82 circuit-ID suboption.
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
Defaults
DHCP snooping rate limiting is disabled.
Command Modes
Interface configuration
Command History
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 150You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.
Related Commands
Configures the recover mechanism.
Displays the DHCP snooping configuration.
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
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 trustYou can verify your settings by entering the show ip dhcp snooping privileged EXEC command.
Related Commands
Displays the DHCP snooping configuration.
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
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-addressYou can verify your settings by entering the show ip dhcp snooping privileged EXEC command.
Related Commands
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 disable DHCP snooping on a VLAN.
ip dhcp snooping vlan vlan-range
no ip dhcp snooping vlan vlan-range
Syntax Description
Defaults
DHCP snooping is disabled on all VLANs.
Command Modes
Global configuration
Command History
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 10You can verify your settings by entering the show ip dhcp snooping privileged EXEC command.
Related Commands
Displays the DHCP snooping configuration.
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 [override] string ASCII-string
no ip dhcp snooping vlan vlan information option format-type circuit-id [override] string
Syntax Description
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
12.2(25)SEE
This command was introduced.
12.2(52)SE
The override keyword was added.
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 port identifier, in the format vlan-mod-port. This command allows you to configure a string of ASCII characters to be the circuit ID. When you want to override the vlan-mod-port format type and instead use the circuit-ID to define subscriber information, use the override keyword.
Note
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-250-0-0This example shows how to configure the option-82 circuit-ID override suboption:
Switch(config-if)# ip dhcp snooping vlan 250 information option format-type circuit-id override string testcustomerYou can verify your settings by entering the show ip dhcp snooping user EXEC command.
Note
Related Commands
Configures the option-82 remote-ID suboption.
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
Defaults
No IGMP filters are applied.
Command Modes
Interface configuration
Command History
Usage Guidelines
You can apply IGMP filters only to Layer 2 physical interfaces; you cannot apply IGMP filters to routed ports, switch virtual interfaces (SVIs), or ports that belong to an EtherChannel group.
An IGMP profile can be applied to one or more switch port interfaces, but one port can have only one profile applied to it.
Examples
This example shows how to apply IGMP profile 22 to a port.
Switch(config)# interface gigabitethernet1/0/2Switch(config-if)# ip igmp filter 22You can verify your setting by using the show running-config privileged EXEC command and by specifying an interface.
Related 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
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
12.1(14)AX
This command was introduced.
12.2(25)EY
The action, deny, and replace keywords were 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:
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Examples
This example shows how to limit to 25 the number of IGMP groups that a port can join.
Switch(config)# interface gigabitethernet1/0/2Switch(config-if)# ip igmp max-groups 25This 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 gigabitethernet2/0/1Switch(config-if)# ip igmp max-groups action replaceYou can verify your setting by using the show running-config privileged EXEC command and by specifying an interface.
Related 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
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
Usage Guidelines
When you are in IGMP profile configuration mode, you can create the profile by using these commands:
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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 40Switch(config-igmp-profile)# permitSwitch(config-igmp-profile)# range 233.1.1.1 233.255.255.255You can verify your settings by using the show ip igmp profile privileged EXEC command.
Related Commands
Applies the IGMP profile to the specified interface.
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
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 snoopingThis example shows how to enable IGMP snooping on VLAN 1:
Switch(config)# ip igmp snooping vlan 1You can verify your settings by entering the show ip igmp snooping privileged EXEC command.
Related Commands
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 query { count count | interval interval} | timer expiry | version]
Syntax Description
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
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 querierThis example shows how to set the IGMP snooping querier maximum response time to 25 seconds:
Switch(config)# ip igmp snooping querier max-response-time 25This example shows how to set the IGMP snooping querier interval time to 60 seconds:
Switch(config)# ip igmp snooping querier query-interval 60This example shows how to set the IGMP snooping querier TCN query count to 25:
Switch(config)# ip igmp snooping querier tcn count 25This example shows how to set the IGMP snooping querier timeout to 60 seconds:
Switch(config)# ip igmp snooping querier timeout expiry 60This example shows how to set the IGMP snooping querier feature to version 2:
Switch(config)# ip igmp snooping querier version 2You can verify your settings by entering the show ip igmp snooping privileged EXEC command.
Related Commands
Enables IGMP report suppression.
Displays the IGMP snooping configuration.
Displays IGMP snooping multicast information.
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 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
Usage Guidelines
IGMP report suppression is supported only when the multicast query has IGMPv1 and IGMPv2 reports. This feature is not supported when the query includes IGMPv3 reports.
The switch uses IGMP report suppression to forward only one IGMP report per multicast router query to multicast devices. When IGMP router suppression is enabled (the default), the switch sends the first IGMP report from all hosts for a group to all the multicast routers. The switch does not send the remaining IGMP reports for the group to the multicast routers. This feature prevents duplicate reports from being sent to the multicast devices.
If the multicast router query includes requests only for IGMPv1 and IGMPv2 reports, the switch forwards only the first IGMPv1 or IGMPv2 report from all hosts for a group to all the multicast routers. If the mulitcast router query also includes requests for IGMPv3 reports, the switch forwards all IGMPv1, IGMPv2, and IGMPv3 reports for a group to the multicast devices.
If you disable IGMP report suppression by entering the no ip igmp snooping report-suppression command, all IGMP reports are forwarded to all the multicast routers.
Examples
This example shows how to disable report suppression:
Switch(config)# no ip igmp snooping report-suppressionYou can verify your settings by entering the show ip igmp snooping privileged EXEC command.
Related Commands
Enables IGMP snooping on the switch or on a VLAN.
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
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-leaveYou can verify your settings by entering the show ip igmp snooping privileged EXEC command.
Related Commands
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
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
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 gigabitethernet1/0/2This example shows how to specify the multicast router learning method as CGMP:
Switch(config)# ip igmp snooping vlan 1 mrouter learn cgmpYou can verify your settings by entering the show ip igmp snooping privileged EXEC command.
Related Commands
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
Defaults
By default, there are no ports statically configured as members of a multicast group.
Command Modes
Global configuration
Command History
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 gigabitethernet1/0/1Configuring port gigabitethernet1/0/1 on group 0100.5e02.0203You can verify your settings by entering the show ip igmp snooping privileged EXEC command.
Related Commands
ip sla responder twamp
Use the ip sla responder twamp global configuration command to configure the switch as a Two-Way Active Measurement Protocol (TWAMP) responder. Use the no form of this command to disable the IP SLA TWAMP responder.
ip sla responder twamp [timeout seconds]
no ip sla responder twamp [timeout seconds]
Syntax Description
timeout seconds
(Optional) Specify the number of seconds a TWAMP session can be inactive before the session ends. The range is 1-604800 seconds. The default is 900 seconds.
Defaults
No IP SLA TWAMP responder is configured.
Command Modes
Global configuration
Command History
Usage Guidelines
After entering the ip sla responder twamp command, you enter IP SLA TWAMP reflector configuration mode, and these configuration commands are available:
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For the TWAMP server and reflector to function, you must also configure a TWAMP control device, which serves as the client and session sender. These functions are not configured on a Cisco device.
Examples
This example shows how to configure a switch as an IP SLA TWAMP responder:
Switch(config)# ip sla responder twampSwitch(config-twamp-ref)# timeout inactivity 900Related Commands
ip sla responder
Enables the Cisco IOS IP Service Level Agreements (SLAs) responder for general IP SLAs operations.
Configures the switch as a Two-Way Active Measurement Protocol (TWAMP) server.
(Optional) Display the IP SLAs standards configured on the switch.
show ip sla twamp connection {detail | requests}
(Optional) Displays the current Cisco IOS IP Service Level Agreements (SLAs) Two-Way Active Measurement Protocol (TWAMP) connections
ip sla server twamp
Use the ip sla server twamp global configuration command to configure the switch as a Two-Way Active Measurement Protocol (TWAMP) server. Use the no form of this command to disable the IP SLA TWAMP server.
ip sla server twamp
no ip sla server twamp
Syntax Description
This command has no arguments or keywords.
Defaults
No IP SLA TWAMP server is configured.
Command Modes
Global configuration
Command History
Usage Guidelines
After entering the ip sla server twamp command, you enter IP SLA TWAMP server configuration mode, and these configuration commands are available:
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For the TWAMP server and reflector to function, you must also configure a TWAMP control device, which serves as the client and session sender. These functions are not configured on a Cisco device.
Examples
This example shows how to configure a switch as an IP SLA TWAMP server:
Switch(config)# ip sla server twampSwitch(config-twamp-srvr)# port 862Switch(config-twamp-srvr)# timer inactivity 540Related Commands
ip sla responder
Enables the Cisco IOS IP Service Level Agreements (SLAs) responder for general IP SLAs operations.
Configures the switch as a Two-Way Active Measurement Protocol (TWAMP) responder.
(Optional) Displays the IP SLAs standards configured on the switch.
show ip sla twamp connection {detail | requests}
(Optional) Displays the current Cisco IOS IP Service Level Agreements (SLAs) Two-Way Active Measurement Protocol (TWAMP) connections.
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
Syntax Description
Defaults
No IP source bindings are configured.
Command Modes
Global configuration
Command History
Usage Guidelines
A static IP source binding entry has an IP address, its associated MAC address, and its associated VLAN number. The entry is based on the MAC address and the VLAN number. If you modify an entry by changing only the IP address, the switch updates the entry instead creating a new one.
Examples
This example shows how to add a static IP source binding:
Switch(config)# ip source binding 0001.1234.1234 vlan 1 172.20.50.5 interface gigabitethernet1/0/1This example shows how to add a static binding and then modify the IP address for it:
Switch(config)# ip source binding 0001.1357.0007 vlan 1 172.20.50.25 interface gigabitethernet1/0/1Switch(config)# ip source binding 0001.1357.0007 vlan 1 172.20.50.30 interface gigabitethernet1/0/1You can verify your settings by entering the show ip source binding privileged EXEC command.
Related Commands
Enables IP source guard on an interface.
Displays the IP source bindings on the switch.
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
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 2You can verify your settings by entering the show ip ssh or show ssh privileged EXEC command.
Related Commands
ip sticky-arp (global configuration)
Use the ip sticky-arp global configuration command to enable sticky Address Resolution Protocol (ARP) on a switch virtual interface (SVI) that belongs to a private VLAN. Use the no form of this command to disable sticky ARP.
ip sticky-arp
no ip sticky-arp
Syntax Description
This command has no arguments or keywords.
Defaults
Sticky ARP is enabled.
Command Modes
Global configuration
Command History
Usage Guidelines
Sticky ARP entries are those learned on private-VLAN SVIs. These entries do not age out.
The ip sticky-arp global configuration command is supported only on SVIs belonging to private VLANs.
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If you enter the ip sticky-arp interface configuration command, it does not take effect.
If you enter the no ip sticky-arp interface configuration command, you do not disable sticky ARP on an interface.
Note
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*Mar 2 00:26:06.967: %IP-3-STCKYARPOVR: Attempt to overwrite Sticky ARP entry: 20.6.2.1, hw: 0000.0602.0001 by hw: 0000.0503.0001•
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Examples
To disable sticky ARP:
Switch(config)# no ip sticky-arpYou can verify your settings by using the show arp privileged EXEC command.
Related Commands
ip sticky-arp (interface configuration)
Use the ip sticky-arp interface configuration command to enable sticky Address Resolution Protocol (ARP) on a switch virtual interface (SVI) or a Layer 3 interface. Use the no form of this command to disable sticky ARP.
ip sticky-arp
no ip sticky-arp
Syntax Description
This command has no arguments or keywords.
Defaults
Sticky ARP is enabled on private-VLAN SVIs.
Sticky ARP is disabled on Layer 3 interfaces and normal SVIs.
Command Modes
Interface configuration
Command History
Usage Guidelines
Sticky ARP entries are those learned on SVIs and Layer 3 interfaces. These entries do not age out.
The ip sticky-arp interface configuration command is only supported on
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On a Layer 3 interface or on an SVI belonging to a normal VLAN
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On private-VLAN SVIs
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If you enter the ip sticky-arp interface configuration command, it does not take effect.
If you enter the no ip sticky-arp interface configuration command, you do not disable sticky ARP on an interface.
Note
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*Mar 2 00:26:06.967: %IP-3-STCKYARPOVR: Attempt to overwrite Sticky ARP entry: 20.6.2.1, hw: 0000.0602.0001 by hw: 0000.0503.0001•
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Examples
To enable sticky ARP on a normal SVI:
Switch(config-if)# ip sticky-arpTo disable sticky ARP on a Layer 3 interface or an SVI:
Switch(config-if)# no ip sticky-arpYou can verify your settings by using the show arp privileged EXEC command.
Related 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 {vlan dhcp-snooping | tracking}[port-security]
no ip verify source {vlan dhcp-snooping | tracking}[port-security]
Syntax Description
Defaults
IP source guard is disabled.
Command Modes
Interface configuration
Command History
12.2(25)EY
This command was introduced.
12.2(52)SE
The vlan dhcp-snooping and tracking keywords were added.
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 on VLANs 10 through 20 on a per-port basis:
Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# ip dhcp snoopingSwitch(config)# ip dhcp snooping vlan 10 20Switch(config)# interface gigabitethernet1/0/1Switch(config-if)# switchport trunk encapsulation dot1qSwitch(config-if)# switchport mode trunkSwitch(config-if)# switchport trunk native vlan 10Switch(config-if)# switchport trunk allowed vlan 11-20Switch(config-if)# no ip dhcp snooping trustSwitch(config-if)# ip verify source vlan dhcp-snoopingSwitch(config)# endSwitch# show ip verify source interface gigabitethernet1/0/1Interface Filter-type Filter-mode IP-address Mac-address Vlan--------- ----------- ----------- --------------- ----------------- ----------Gi1/0/1 ip-mac active 10.0.0.1 10Gi1/0/1 ip-mac active deny-all 11-20Switch#This example shows how to enable IP port security with IP-MAC filters on a Layer 2 access port:
Switch# configure terminalEnter configuration commands, one per line. End with CNTL/Z.Switch(config)# ip device trackingSwitch(config)# interface gigabitEthernet1/0/3Switch(config-if)# switchport mode accessSwitch(config-if)# switchport access vlan 1Switch(config-if)# ip device tracking maximum 5Switch(config-if)# switchport port-securitySwitch(config-if)# switchport port-security maximum 5Switch(config-if)# ip verify source tracking port-securitySwitch(config-if)# endVerify your settings by entering the show ip verify source privileged EXEC command.
Related Commands
ip vrf (global configuration)
Use the ip-vrf global configuration command to configure a virtual private network (VPN) routing/forwarding (VRF) routing table and to enter VRF configuration mode. Use the no form of this command to remove a VRF routing table and to return to global configuration mode.
ip vrf vrf-name
no ip vrf vrf-name
Note
Syntax Description
Defaults
No VRFs are defined.
No import or export lists are associated with a VRF.
No route maps are associated with a VRF.
Command Modes
Global configuration or router configuration
Command History
Usage Guidelines
Entering the ip vrf command enables the VRF configuration mode. These configuration commands are available:
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To return to global configuration mode, use the exit command. To return to privileged EXEC mode, use the end command.
The switch supports a total of 26 VRFs and VPNs.
Use an import route map when an application requires finer control over the routes imported into a VRF than provided by the import and export extended communities configured for the importing and exporting VRF. The import map command associates a route map with the specified VRF. By using a route map, you can filter routes that are eligible for import into a VRF, based on the route target extended community attributes of the route. The route map might deny access to selected routes from a community that is on the import list.
If you set a maximum routes threshold, the switch rejects routes when the threshold limit is reached. If you enter warn-only, the switch issues a syslog error message when the maximum number of VRF routes exceeds the allowed limit, but still allows additional routes.
An RD creates routing and forwarding tables and specifies the default route distinguisher for a VPN. You must configure a route distinguisher for a VRF to be functional. The RD is added to the beginning of the customer's IPv4 prefixes to change them into globally unique VPN-IPv4 prefixes.
The route target specifies a target VPN extended community. Like a route-distinguisher, an extended community is composed of either an autonomous system number and an arbitrary number or an IP address and an arbitrary number.
The ip vrf vrf-name command creates a VRF routing table and a Cisco Express Forwarding (CEF) forwarding table, both named vrf-name. Associated with these tables is the default route distinguisher value route-distinguisher.
Examples
This example shows how to create the VRF named vpn1, enter VRF configuration mode, and import a route map to the VRF:
Switch(config)# ip vrf vpn1Switch(config-vrf)# rd 100:2Switch(config-vrf)# route-target both 100:2Switch(config-vrf)# route-target import 100:1Related Commands
ip vrf (interface configuration)
Use the ip-vrf interface configuration command to associate a virtual private network (VPN) routing/forwarding (VRF) routing table or a route map with an interface. Use the no form of this command to disassociate the VRF routing table or route map.
ip vrf {forwarding table-name | sitemap route-map-name}
no ip vrf {forwarding table-name | sitemap route-map-name}
Note
Syntax Description
forwarding table-name
Specify a VRF forwarding table name for the interface.
sitemap route-map-name
Specify a VRF route map for routes received from this site.
Defaults
The default for an interface is the global routing table.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ip vrf forwarding command to associate an interface with a VRF. Executing this command on an interface removes the IP address. You should then reconfigure the IP address.
Examples
This example shows how to link the VRF named vpn1 to a port:
Switch(config)# interface gigabitethernet1/0/2Switch(config-if)# ip vrf forwarding vpn1Related Commands
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
Syntax Description
access-list-name
Name of the IPv6 access list. Names cannot contain a space or quotation mark or begin with a number.
Defaults
No IPv6 access list is defined.
Command Modes
Global configuration
Command History
Usage Guidelines
To configure the dual IPv4 and IPv6 template, enter the sdm prefer dual-ipv4-and-ipv6 {default | routing | vlan) global configuration command, and reload the switch.
The ipv6 access-list command is similar to the ip access-list command, but it is IPv6-specific.
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 deny (IPv6 access-list configuration) 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.
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.
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 to switch virtual interfaces for routed ACLs, but only inbound IPv6 ACLs to Layer 2 interfaces for port ACLs.
Note
Examples
This example puts the switch in IPv6 access list configuration mode, 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 list2Switch(config-ipv6-acl)# deny FE80:0:0:2::/64 anySwitch(config-ipv6-acl)# permit any anySwitch(config-ipv6-acl)# exitSwitch(config)# interface gigabitethernet0/3Switch(config-if)# no switchportSwitch(config-if)# ipv6 address 2001::/64 eui-64Switch(config-if)# ipv6 traffic-filter list2 out
Note
Related Commands
ipv6 address dhcp
Use the ipv6 address dhcp interface configuration command to acquire an IPv6 address on an interface from the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server. To remove the address from the interface, use the no form of this command.
ipv6 address dhcp [rapid-commit]
no ipv6 address dhcp [rapid-commit]
Note
Syntax Description
Defaults
No default is defined.
Command Modes
Interface configuration
Command History
Usage Guidelines
To configure the dual IPv4 and IPv6 template, enter the sdm prefer dual-ipv4-and-ipv6 {default | routing | vlan} global configuration command, and reload the switch.
The ipv6 address dhcp interface configuration command allows any interface to dynamically learn its IPv6 address by using DHCP.
The rapid-commit keyword enables the use of the two-message exchange for address allocation and other configuration. If it is enabled, the client includes the rapid-commit option in a solicit message.
Examples
This example shows how to acquire an IPv6 address and to enable the rapid-commit option:
Switch(config)# interface gigabitethernet0/1Switch(config-if)# ipv6 address dhcp rapid-commitYou can verify your settings by using the show ipv6 dhcp interface privileged EXEC command.
Related Commands
ipv6 dhcp client request vendor
Use the ipv6 dhcp client request interface configuration command to configure an IPv6 client to request an option from a Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server. To remove the request, use the no form of this command.
ipv6 dhcp client request vendor
no ipv6 dhcp client request vendor
Note
Syntax Description
This command has no arguments or keywords.
Defaults
No default is defined.
Command Modes
Interface configuration
Command History
Usage Guidelines
To configure the dual IPv4 and IPv6 template, enter the sdm prefer dual-ipv4-and-ipv6 {default | routing | vlan} global configuration command, and reload the switch.
Use the ipv6 dhcp client request vendor interface configuration to request a vendor-specific option. When enabled, the command is verified only when an IPv6 address is acquired from DHCP. If you enter the command after the interface has an IPv6 address, the command does not take effect until the next time the client acquires an IPv6 address from DHCP.
Examples
This example shows how to enable the request vendor-specific option.
Switch(config)# interface gigabitethernet0/1Switch(config-if)# ipv6 dhcp client request vendor-specificRelated Commands
ipv6 dhcp ping packets
Use the ipv6 dhcp ping packets global configuration command to specify the number of packets a Dynamic Host Configuration Protocol for IPv6 (DHCPv6) server sends to a pool address as part of a ping operation. To prevent the server from pinging pool addresses, use the no form of this command.
ipv6 dhcp ping packets number
no ipv6 dhcp ping packets
Note
Syntax Description
number
The number of ping packets sent before the address is assigned to a requesting client. The range is 0 to 10.
Defaults
The default is 0.
Command Modes
Global configuration
Command History
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 DHCPv6 server pings a pool address before assigning it to a requesting client. An unanswered ping indicates that the address is not in use and the server assigns the address to the requesting client.
Setting the number argument to 0 turns off the DHCPv6 server ping operation.
Examples
This example specifies two ping attempts by the DHCPv6 server before further ping attempts stop:
Switch(config)# ipv6 dhcp ping packets 2Related Commands
Clears an address conflict from the DHCPv6 server database.
Displays address conflicts found by a DHCPv6 server or reported through a DECLINE message from a client.
ipv6 dhcp pool
Use the ipv6 dhcp pool global configuration command to enter Dynamic Host Configuration Protocol for IPv6 (DHCPv6) pool configuration mode. Use the no form of this command to return to the default settings.
ipv6 dhcp pool poolname
no ipv6 dhcp pool poolname
Note
Syntax Description
poolname
User-defined name for the DHCPv6 pool. The pool name can be a symbolic string (such as Engineering) or an integer (such as 0).
Defaults
No default is defined.
Command Modes
Global configuration
Command History
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.
DHCPv6 pool configuration mode commands:
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After you create the DHCPv6 configuration information pool, use the ipv6 dhcp server interface configuration command to associate the pool with a server on an interface. However, if you do not configure an information pool, you still need to use the ipv6 dhcp server interface configuration command to enable the DHCPv6 server function on an interface.
When you associate a DHCPv6 pool with an interface, only that pool services requests on the associated interface. The pool also services other interfaces. If you do not associate a DHCPv6 pool with an interface, it can service requests on any interface.
Not using any IPv6 address prefix means that the pool only returns configured options.
The link-address keyword allows matching of a link-address without necessarily allocating an address. You can match the pool from multiple relays by using multiple link-address configuration commands inside a pool.
Because a longest match is performed on either the address pool information or the link information, you can configure one pool to allocate addresses and another pool on a subprefix that only returns configured options.
Examples
This example shows how to configure a pool called engineering with an IPv6 address prefix:
Switch# configure terminalSwitch(config)# ipv6 dhcp pool engineeringSwitch(config-dhcpv6)# address prefix 2001:1000::0/64Switch(config-dhcpv6)# endThis example shows how to configure a pool called testgroup with three link-address prefixes and an IPv6 address prefix:
Switch# configure terminalSwitch(config)# ipv6 dhcp pool testgroupSwitch(config-dhcpv6)# link-address 2001:1001::0/64Switch(config-dhcpv6)# link-address 2001:1002::0/64Switch(config-dhcpv6)# link-address 2001:2000::0/48Switch(config-dhcpv6)# address prefix 2001:1003::0/64Switch(config-dhcpv6)# endThis example shows how to configure a pool called 350 with vendor-specific options:
Switch# configure terminalSwitch(config)# ipv6 dhcp pool 350Switch(config-dhcpv6)# vendor-specific 9Switch(config-dhcpv6-vs)# suboption 1 address 1000:235D::1Switch(config-dhcpv6-vs)# suboption 2 ascii "IP-Phone"Switch(config-dhcpv6-vs)# endRelated Commands
Enables DHCPv6 service on an interface.
show ipv6 dhcp pool
Displays DHCPv6 configuration pool information.
ipv6 dhcp server
Use the ipv6 dhcp server interface configuration command to enable Dynamic Host Configuration Protocol for IPv6 (DHCPv6) service on an interface. To disable DHCPv6 service on an interface, use the no form of this command.
ipv6 dhcp server [poolname | automatic] [allow-hint] [rapid-commit] [preference value]
no ipv6 dhcp server
Note
Syntax Description
Defaults
By default, no DHCPv6 packets are serviced on the interface.
Command Modes
Interface configuration
Command History
Usage Guidelines
The ipv6 dhcp server interface configuration command enables DHCPv6 service on a specified interface.
If you enter the automatic keyword, the system automatically determine which pool to use when allocating addresses for a client. When the server receives an IPv6 DHCP packet, the server determines if it was received from a DHCP relay or if it was directly received from the client. If the packet was received from a relay, the server verifies the link-address field inside the packet associated with the first relay that is closest to the client. The server matches this link-address against all address prefix and link-address configurations in IPv6 DHCP pools to find the longest prefix match. The server selects the pool associated with the longest match.
If the packet was received directly from the client, the server performs this same matching, but it uses all the IPv6 addresses configured on the incoming interface when performing the match. Once again, the server selects the longest prefix match.
If you enter the allow-hint keyword, the server allocates a valid client-suggested address in the solicit and request messages. The prefix address is valid if it is in the associated local prefix address pool and it is not assigned to a device. If the allow-hint keyword is not specified, the server ignores the client hint, and an address is allocated from the free list in the pool.
If you configure the preference keyword with a value other than 0, the server adds a preference option to carry the preference value for the advertise messages. This action affects the selection of a server by the client. Any advertise message that does not include a preference option is considered to have a preference value of 0. If the client receives an advertise message with a preference value of 255, the client immediately sends a request message to the server from which the message was received.
Entering the rapid-commit keyword enables the use of the two-message exchange.
The DHCPv6 client, server, and relay functions are mutually exclusive on an interface. When one of these functions is already enabled and you try to configure a different function on the same interface, the switch returns one of these messages:
Interface is in DHCP client modeInterface is in DHCP server modeInterface is in DHCP relay modeExamples
This example enables DHCPv6 for the pool named testgroup:
Switch(config-if)# ipv6 dhcp server testgroupRelated Commands
Configures a DHCPv6 pool and enters DHCPv6 pool configuration mode.
show ipv6 dhcp interface
Displays DHCPv6 interface information.
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 switch stack or the VLAN.
ipv6 mld snooping [vlan vlan-id]
no ipv6 mld snooping [vlan vlan-id]
Note
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
Usage Guidelines
To configure the d
