For troubleshooting I would recommend to run a simultaneous tcpdump on interface "
0.0
" with a filter on "
arp
" on both machines in your device service cluster and to trigger a failover. (Use the "
-s 0
" option for full packet size and "
-w /var/tmp/.pcap
" for dump to file, please)
I.e.
tcpdump -vi 0.0 -c 10000 -s 0 arp -w /var/tmp/trace.$HOSTNAME.pcap
In wireshark you can apply a filter of
arp.isgratuitous
to display G-ARPs only.
As written by surgeon, it might happen that due to the pure amount of G-ARPs some might get lost.
Virtual IPs configured in non-locally-attached networks wont send G-ARPs. Instead you can expect seeing G-ARPs for floating self IPs which are used as next hops.
Don´t be irritated to see G-ARPs for local-only Self IPs (especially those to be used for device service cluster configuration heartbeat/config-sync/mirror) as well.
Make sure, not to set the "
link down on failover
" (Device Management >> Device Groups >> : Failover; just leave it in the default setting of "
0.0
") as it might trigger a spanning tree reconvergence after a failover resulting in lost G-ARPs.
Cheers, Stephan