Adjusting The Arp Aging Timer - Juniper JUNOS 10.1 - CONFIGURATION GUIDE 1-2010 Configuration Manual

By default, the router responds to gratuitous ARP requests. On Ethernet interfaces,
you can disable responses to gratuitous ARP requests. To disable responses to
gratuitous ARP requests, include the
interfaces interface-name]
To return to the default—that is, to respond to gratuitous ARP requests—delete the
no-gratuitous-arp-request
Gratuitous ARP replies are reply packets sent to the broadcast MAC address with the
target IP address set to be the same as the sender s IP address. When the router
receives a gratuitous ARP reply, the router can insert an entry for that reply in the
ARP cache.
By default, updating the ARP cache on gratuitous ARP replies is disabled on the
router. On Ethernet interfaces, you can enable handling of gratuitous ARP replies on
a specific interface by including the
interface-name]
To restore the default behavior, include the
[edit interfaces interface-name]

Adjusting the ARP Aging Timer

By default, the ARP aging timer is set at 20 minutes. In most network environments,
this default value does not cause a problem. However, in environments with many
directly attached hosts, such as metro Ethernet, the number of ARP entries to update
can be high. In such environments, you might want to increase the amount of time
between ARP updates by configuring the ARP aging timer.
To configure the ARP aging timer, include the
arp]
The aging timer range is from 20 through 240 minutes. The timer value you configure
takes effect as ARP entries expire. In other words, each subsequent refreshed ARP
entry receives the new timer value. The new timer value does not apply to ARP
entries that exist at the time you commit the configuration.
For more information about statements you can configure at the
hierarchy level, see the JUNOS System Basics Configuration Guide.
hierarchy level:
[edit interfaces interface-name]
no-gratuitous-arp-request;
statement from the configuration:
[edit]
user@host# delete interfaces interface-name no-gratuitous-arp-request
hierarchy level:
[edit interfaces interface-name]
gratuitous-arp-reply;
[edit interfaces interface-name]
no-gratuitous-arp-reply;
hierarchy level:
[edit system arp]
aging-timer minutes;
Chapter 33: Configuring Ethernet Interfaces
no-gratuitous-arp-request
statement at the
gratuitous-arp-reply
no-gratuitous-arp-reply
hierarchy level:
statement at the
aging-timer
Adjusting the ARP Aging Timer
statement at the
[edit
[edit interfaces
statement at the
[edit system
[edit system]
615