ipf and ipnat stopped working, no routing between nics.

[Erik Norgaard]

Daniel A. wrote:
> Hi,
> I run a FreeBSD 6.0 at home in my closet.
> Yesterday, while I was linking IRCd services with a friend of mine, my router
> completely stopped routing any packets between the internal nic (sis0) and
> the external nic (rl0).
> The only thing that I can think of, whoich could have caused this, is that I
> ran ettercap on the server to diagnose why our servers wouldnt link. I did NOT
> run any ARP poisoning or DNS spoofing attacks on myself.
> But I didnt notice if the routing stopped at that point, or later, because I
> could always connect to my server, and the server could always connect to the
> internet. The situation is still the same.
> 
> I have tried to do
> - "ipf -Fa -f /etc/ipf.rules; ipnat -FC -f /etc/ipnat.rules" - Didnt help
> - "cd /etc/rc.d; ./ipfilter restart; ./ipnat restart" - Didnt help
> - Launch ettercap again and exit "cleanly" after telling it to stop sniffing.
> A tcpdump reveals that, indeed, no packets at all make it from sis0 to rl0.
> So my conclusion is that ipnat "forgot" how to route between the two
> interfaces.
> 
> Could anyone please give some pointers?

did you check

# sysctl -a |grep forward

you should have

net.inet.ip.forwarding: 1
net.inet.ip.fastforwarding: 0
net.inet6.ip6.forwarding: 0

Erik
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