On Thursday 29 April 2004 15:47, Sven Schuster wrote: > > iptables -t nat -A POSTROUTING -p tcp -i eth1 -s 10.0.0.0/8 \ > -d 10.0.0.253 --dport 25 -j SNAT --to 10.0.0.xx:25 > > where xx would be the ip of your firewall. Now both the packets > from the client to the server and the returning packets from the > server to the client will travel through your firewall. Thanks for the reply - the explanation sounds right, and I think I understand what's going on now - I won't be able to test the theory out until next week - I just didn't want to seem rude by staying silent to date :) Cheers, Gavin.