Change the ARP Aging Timeout for an Interface

An aging timer is triggered when a dynamic entry is added to the ARP cache and is reset if an ARP reply is received. The aging timer ensures that the ARP cache does not retain invalid learned entries. An entry can become invalid when the device with the MAC address of the entry is no longer on the network.

1. Access global configuration mode.
   

   device# configure terminal
   

2. Access the interface on which you are changing the aging timeout.
   

   device(config)# interface ethernet 0/1
   

3. Specify the new timeout value.
   

   device(conf-if-eth-0/1)# ip arp-aging-timeout 100
   

   Valid values range from 0 through 240 minutes.

The following example summarizes the commands in this procedure.

device# configure terminal
device(config)# interface ethernet 0/1
device(conf-if-eth-0/1)# ip arp-aging-timeout 100