I'll keep this brief but may overlook some details. I have a client who
has two networks - #1 is with 5 servers accessible from the internet and
each box has a second NIC connecting to the #2 network to some other
servers. #1 network is going to be using 10.10.11.x with monowall set up
to do 1:1 translation with the public IPs. Network #2 is 192.168.0.x.

I've been trying for a week to make this work and my last attempt went
like this. I set up the monowall and put a notebook and a server behind
it. Opened up the rules and everything's accessible. We then added the
public IPs of the servers on the #1 network to the proxy arp and to the
1:1 translation, and changed the public IPs on the server to the
10.10.11.x. None of those servers can get out and you can't see them from
the outside. However, we then moved the IPs from the notebook and server
that were working over to a couple of the non-working servers and vice
versa and the non-working servers start working and the notebook and test
server stop working. I then changed the the 1:1 translation of one of the
working IPs from x.x.x.36:10.10.11.36 to x.x.x.36:10.10.11.46 and it
stopped working.

Any suggestions?