• You may need to enter a static entry in the cache if there is no response to a n
ARP broadcast message. For example, some applications may not respond
to ARP requests or the response arrives too late, causing network operations
to time out.
Example
Console(config)#arp 10.1.0.19 01-02-03-04-05-06
Console(config)#
Related Commands
clear arp-cache
show arp
arp timeout
This command sets the aging time for dynamic entries in the Address Resolutio n
Protocol (ARP) cache. Use the
no
form to restore the default.
Syntax
arp-timeout
seconds
no arp-timeout
seconds - The time a dynamic entry remains in the ARP cache.
(Range: 300-86400; 86400 is one day)
Default Setting
1200 seconds (20 minutes)
Command Mode
Global Configuration
Command Usage
• When a ARP entry expires, it is deleted from the cache an d an ARP req uest
packet is sent to re-establish the MAC address.
• The aging time determines how long dynamic entr ies remai n in the cache. I f
the timeout is too short, the router may t ie up resour ces by repe ating ARP
requests for addresses recently flushed from the table.
• Use the show arp command (page 41-34) t o display the cu rrent c ache
timeout value.
Example
This example sets the ARP cache timeout for 15 minutes (i.e., 900 seconds).
Console(config)#arp timeout 900
Console(config)#
41-33Address Resolution Protocol (ARP)
41