I am new to iptables so please be kind.... My host is RH 7.2 with the latest updates as of last night. My iptables version is 1.2.4 on kernel 2.4.9.
I am starting with a minimal rule set and moving out. Right now, my base rule is just for masquerading on nat: iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE This works fine for every service I have tested -> web, icq, sending and receiving mail to other hosts, etc. I have set up a port forward from my firewall box which works as far as receiving mail on an internal server is concerned: iptables -t nat -A PREROUTING -p tcp --dport 25 -j DNAT --to 192.168.1.3 I can receive mail all day long. However, when I try to send mail, the attempt dies saying the connection has timed out in the mail queue messages. I am unable to telnet out on port 25 to a known good host, so I know I am missing something. When I try to telnet from the firewall, it works fine, but none of my internal hosts appear able to telnet out on port 25 to a mail host, which is why I am assuming mail is not working for outgoing messages. Any ideas? Thanks, Chris
