[CentOS] Not firewall, but what?

[Gordon Messmer]

On 05/11/2010 06:32 AM, Jussi Hirvi wrote:
> Ok. But this error does not occur on my other CentOS 5 box (mailserver,
> non-xen) which also has 2 nics for 2 public ip segments. There input-nic
> is always = outputnic. And I have done nothing special to achieve this
> (pure "linux magic"). That's why I "blame" bridges - they are the most
> notable difference between these two machines.

That's odd.  Is there any output on that host from "ip rule show"?  What 
about:

# ip rule show
# ip rule show | awk '{print $NF}' | sort | uniq | \
   while read table ; do echo ; echo "  $table" ;
   ip route show table "$table" ; done