NAT stops working (more)

[Daniel Wittenberg]

The only ideas people came up with was the conntrack table, but I know
that's not a problem (I see no errors at all, plus manually checking it
is fine).  So now I'm wondering how I can debug netfilter itself?
kernel debugger?  I can see the packets come into the host using
tcpdump/ethereal, but they don't go out the internal interface, so not
sure how to "track" the packet within the kernel.  Ideas?

Thanks,
Dan