IP Routing Features

Configuring IP Parameters for Routing Switches

 

routers, including ProCurve routing switches, can be configured to reply

 

to ARP requests from one network on behalf of devices on another

 

network. See “Enabling Proxy ARP” below.

 

 

N o t e

If the routing switch receives an ARP request packet that it is unable to deliver

 

to the final destination because of the ARP timeout and no ARP response is

 

received (the routing switch knows of no route to the destination address),

 

the routing switch sends an ICMP Host Unreachable message to the source.

 

 

Changing the ARP Aging Period

The ARP age is the amount of time the switch keeps a MAC address learned through ARP in the ARP cache. The switch resets the timer to zero each time the ARP entry is refreshed and removes the entry if the timer reaches the ARP age.

You can increase the ARP age timeout maximum to 24 hours or more with this command:

Syntax: [no] ip arp-age <[1...1440] infinite>

Allows the ARP age to be set from 1 to 1440 minutes (24 hours). If the option “infinite” is configured, the internal ARP age timeout is set to 99,999,999 seconds (approximately 3.2 years). An arp-agevalue of 0 (zero) is stored in the configuration file to indicate that “infinite” has been configured. This value also displays with the show commands and in the menu display (Menu > Switch Configuration > IP Config).

Default: 20 minutes.

ProCurve(config)# ip arp-age 1000

Figure 7-3. Example of Setting the ARP Age Timeout to 1000 Minutes

To view the value of Arp Age timer, enter the show ip command as shown in Figure 7-4.

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