This article describes the behavior of SRX updating the ARP cache, when gratuitous ARP requests and replies are received.

Gratuitous ARP request :

• Passive learning is used to update the ARP cache on the VRRP backup router.

• The following command updates the ARP cache, when a gratuitous ARP request is received:

  set system arp passive-learning

• Apart from the ARP cache update behavior, by default, SRX responds to the gratuitous ARP request. This can be disabled via the following command:
  

  set interfaces <interface-name> no-gratuitous-arp-request

Gratuitous ARP reply :

• By default, SRX does not update the ARP cache, when a gratuitous ARP reply broadcast is received.

• This can be enabled via the following command:
  

  set interfaces <interface-name> gratuitous-arp-reply

• This can be reverted to the default behavior by configuring no-gratuitous-arp-reply .

• [SRX] ARP failed to update when the gratuitous ARP reply was received