Sets how long a dynamic Address Resolution Protocol (ARP) entry stays in the ARP cache. The aging timer is reset each time an ARP reply is received.
ARP aging timeout is globally enabled and set to 25 minutes.
Interface subtype configuration mode
When the device places an entry in the ARP cache, the device also starts an aging timer for the entry. The aging timer ensures that the ARP cache does not retain learned entries that are no longer valid. An entry can become invalid when the device with the MAC address of the entry is no longer on the network.
The aging timer is reset each time an ARP reply is received.
Aging out affects dynamic (learned) entries only. Static entries do not age out.
You can modify the ARP aging timeout only at the interface level, but not at the global level.
To prevent entries from aging out, enter ip arp-aging-timeout 0.
The no form of the command restores the default aging timeout of 25 minutes.
The following command sets the ARP aging timeout to 100 minutes on an interface.
device(config)# interface ethernet 3/4 device(conf-if-eth-3/4)# ip arp-aging-timeout 100
The following command restores the ARP aging timeout to the default value on an interface.
device(config)# interface ethernet 3/4 device(conf-if-eth-3/4)# no ip arp-aging-timeout