Carp strange behavior

[Rafael Ganascim]

Hi list,

I have multiple FreeBSD firewalls with carp working well. I have no problem
and the vast majority of firewalls works perfectly.

But now, I'm with problems with a simple firewall cluster with carp that
the state randomly goes to MASTER and randomly returns to BACKUP.

Looking to the L1/L2 tests, I have no rx/tx erros, buffers miss, in/out
drops , etc. The physical conection between the firewalls looks good.

Monitoring the interfaces/buffers/mbufs/virtual memory with netstat,
vmstat.... no errors was found.

Using tcpdump, I can see that in the exact moment of the state change, the
currently master's firewall stop sending multicasts to the 224.0.0.18
during some seconds and the state change occurs.

The system:
# uname -a
FreeBSD fw-cj-01 9.1-RELEASE FreeBSD 9.1-RELEASE #0: Thu Feb 28 13:18:41
BRT 2013     root at fw-new-01:/usr/obj/usr/src/sys/DEDICr9v1CoreX64  amd64


Now, how can I debug why carp stops to send multicast packets?


Best Regards,

Rafael