arp learning passive enable
Function
The arp learning passive enable command enables passive ARP that allows a backup device in a VRRP backup group to learn ARP entries when receiving an ARP request message sent to a virtual IP address.
The undo arp learning passive enable command disables passive ARP.
Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support this command.
Usage Guidelines
Usage Scenario
When the master and backup devices in a VRRP backup group receive an ARP request message sent to a virtual IP address, only the master device learns ARP entries and responds to the sender with the virtual MAC address. If a link or device fault causes the VRRP backup group to perform a master/backup switchover, a backup device must learn ARP entries on the user side before taking over traffic. As a result, service traffic is interrupted for a short time.
After you run the arp learning passive enable command to enable passive ARP, a backup device in a VRRP backup group learns ARP entries when receiving an ARP request message sent to a virtual IP address. If a VRRP backup group performs a master/backup switchover, the new master device can take over traffic without needing to relearn ARP entries, ensuring service continuity.
Precautions
Passive ARP cannot be configured together with strict ARP entry learning.
The passive ARP function is invalid for a VRRP group created on a VLANIF interface.