Address Resolution Protocol (ARP) Commands

This section describes the commands you use to configure ARP and to view ARP information on the switch. ARP associates IP addresses with MAC addresses and stores the information as ARP entries in the ARP cache.

arp

This command creates an ARP entry. The value for <ipaddress> is the IP address of a device on a subnet attached to an existing routing interface. <macaddr> is a unicast MAC address for that device. The format of the MAC address is 6 two-digit hexadecimal numbers that are separated by colons, for example 00:06:29:32:81:40.

• Format: arp <ipaddress> <macaddr>
• Mode: Global Config

no arp

This command deletes an ARP entry. The value for <ipaddress> is the IP address of a device on a subnet attached to an existing routing interface.

• Format: no arp <ipaddress>
• Mode: Global Config

ip proxy-arp

This command enables proxy ARP on a router interface. Without proxy ARP, a device only responds to an ARP request if the target IP address is an address configured on the interface where the ARP request arrived. With proxy ARP, the device may also respond if the target IP address is reachable. The device only responds if all next hops in its route to the destination are through interfaces other than the interface that received the ARP request.

• Default: enabled
• Format: ip proxy-arp
• Mode: Interface Config

no ip proxy-arp

This command disables proxy ARP on a router interface.

• Format: no ip proxy-arp
• Mode: Interface Config

arp cachesize

This command configures the ARP cache size. The ARP cache size value is a platform specific integer value. The default size also varies depending on the platform.

• Format: arp cachesize <platform specific integer value>
• Mode: Global Config

no arp cachesize

This command configures the default ARP cache size.

• Format: no arp cachesize
• Mode: Global Config

arp dynamicrenew

This command enables the ARP component to automatically renew dynamic ARP entries when they age out.

• Default: disabled
• Format: arp dynamicrenew
• Mode: Global Config

no arp dynamicrenew

This command prevents dynamic ARP entries from renewing when they age out.

• Format: no arp dynamicrenew
• Mode: Global Config

arp purge

This command causes the specified IP address to be removed from the ARP cache. Only entries of type dynamic or gateway are affected by this command.

• Format: arp purge <ipaddr>
• Mode: Privileged EXEC

arp resptime

This command configures the ARP request response timeout. The value for <seconds> is a valid positive integer, which represents the IP ARP entry response timeout time in seconds. The range for <seconds> is between 1-10 seconds.

• Default: 1
• Format: arp resptime <seconds>
• Mode: Global Config

no arp resptime

This command configures the default ARP request response timeout.

• Format: no arp resptime
• Mode: Global Config

arp retries

This command configures the ARP count of maximum request for retries. The value for <retries> is an integer, which represents the maximum number of request for retries. The range for <retries> is an integer between 0-10 retries.

• Default: 4
• Format: arp retries <entries>
• Mode: Global Config

no arp retries

This command configures the default ARP count of maximum request for retries.

• Format: no arp retries
• Mode: Global Config

arp timeout

This command configures the ARP entry ageout time. The value for <seconds> is a valid positive integer, which represents the IP ARP entry ageout time in seconds. The range for <seconds> is between 15-21600 seconds.

• Default: 1200
• Format: arp timeout <seconds>
• Mode: Global Config

no arp timeout

This command configures the default ARP entry ageout time.

• Format: no arp timeout
• Mode: Global Config

clear arp-cache

This command causes all ARP entries of type dynamic to be removed from the ARP cache. If the gateway keyword is specified, the dynamic entries of type gateway are purged as well.

• Format: clear arp-cache [gateway]
• Mode: Privileged EXEC

clear arp-switch

Use this command to clear the contents of the switch’s Address Resolution Protocol (ARP) table that contains entries learned through the Management port. To observe whether this command is successful, ping from the remote system to the DUT. Issue the show arp switch command to see the ARP entries. Then issue the clear apr-switch command and check the show arp-switch entries. There will be no more arp entries.

• Format: clear arp-switch
• Mode: Privileged EXEC

show arp

This command displays the Address Resolution Protocol (ARP) cache. The displayed results are not the total ARP entries. To view the total ARP entries, the operator should view the show arp results in conjunction with the show arp switch results.

• Format: show arp
• Mode: Privileged EXEC
• Age Time (seconds): The time it takes for an ARP entry to age out. This is configurable. Age time is measured in seconds.
• Response Time (seconds): The time it takes for an ARP request timeout. This value is configurable. Response time is measured in seconds.
• Retries: The maximum number of times an ARP request is retried. This value is configurable.
• Cache Size: The maximum number of entries in the ARP table. This value is configurable.
• Dynamic Renew Mode: Displays whether the ARP component automatically attempts to renew dynamic ARP entries when they age out.
• Total Entry Count Current/Peak: The total entries in the ARP table and the peak entry count in the ARP table.
• Static Entry Count Configured / Active / Max: The static entry count that is configured in the ARP table, number of entires present in the ARP table and maximum static entry count in the ARP table.

The following are displayed for each ARP entry.

• IP Address: The IP address of a device on a subnet attached to an existing routing interface.
• MAC Address: The hardware MAC address of that device.
• Interface: The routing unit/slot/port associated with the device ARP entry.
• Type: The type that is configurable. The possible values are Local, Gateway,Dynamic and Static.
• Age: The current age of the ARP entry since last refresh (in hh:mm:ss format)

show arp brief

This command displays the brief Address Resolution Protocol (ARP) table information.

• Format: show arp brief
• Mode: Privileged EXEC
• Age Time (seconds): The time it takes for an ARP entry to age out. This value is configurable. Age time is measured in seconds.
• Response Time (seconds): The time it takes for an ARP request timeout. This value is configurable. Response time is measured in seconds.
• Retries: The maximum number of times an ARP request is retried. This value is configurable.
• Cache Size: The maximum number of entries in the ARP table. This value is configurable.
• Dynamic Renew Mode: Displays whether the ARP component automatically attempts to renew dynamic ARP entries when they age out.
• Total Entry Count Current/Peak: The total entries in the ARP table and the peak entry count in the ARP table.
• Static Entry Count Configured / Active / Max: The static entry count that is configured in the ARP table, number of entires present in the ARP table and maximum static entry count in the ARP table.

show arp switch

This command displays the contents of the switch’s Address Resolution Protocol (ARP) table.

• Format: show arp switch
• Mode: Privileged EXEC
• MAC Address: The hardware MAC address of that device.
• IP Address: The IP address of a device on a subnet attached to the switch.
• Interface: The routing unit/slot/port associated with the device’s ARP entry.