I have a quad interface box setup, the other day after adding a forward rule, packets that were going to eth3 sourced from the same ip subnet(A.B.C.D/24) that should of gotten redirects started to become natted. The work around was to add iptables -t nat -I POSTROUTING -s A.B.C.D/24 -o eth3 -j ACCEPT and the packet were no longer being natted. This is a RH9 box with iptables-1.2.7a-2 running either kernel-2.4.20-24.9 or kernel-2.4.20-20.9. INPUT and FORWARD are default DROP with a masqeuaring on all 4 interfaces with exclusion rules on three of them. I have filed a bug report with Redhat already, so this is an FYI for any other souls in the same boat like me. Ted
