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5820-24XG & gratuitous ARP

Stefan Neher
Occasional Contributor

5820-24XG & gratuitous ARP

Hi everybody,

 

i configured two brand new 5820-24XG with irf as core switches.
everything works fine so far, except one thing:

the switches act as routers, the default route points to a firewall cluster.
when there's a failover from firewall node 1 to firewall node 2, the mac adress of the cluster ip changes.
the firewall send gratuitous ARPs, to make the switches being aware of the new mac adress. i double-checked it with wireshark.
the 5820-24XG are configured with "gratuitous-arp-learning enable" by default.
but the 5820-24XG ignore it. there's still the wrong mac adress in the arp table. it set the arp cache lifetime to one minute to minimize the routing outage. i didn't configure any arp security, so i believe gratuitous-arp-learning should work.

 

Any suggestions are appreciated...

 

1 REPLY
manuel.bitzi
Trusted Contributor

Re: 5820-24XG & gratuitous ARP

Hi Stefan

 

I've tested it with our 5820 (R1211p04) and the unix tool arping. Works great.

What type of firewall do you use? Whats the gratuitous arp packet like?

 

br

Manuel 

H3CSE, MASE Network Infrastructure [2011], Switzerland