I am running the IMAP daemon on Red Hat Linux 8.0. It runs with SquirrelMail 1.4.1 and Apache 2.0, and most everything is working fine. I have also written a mail checking program to check my mail on other mail accounts which also works. The oddity is that if I am on the Mail/Web server machine and do:

telnet localhost 143
or
telnet 192.168.1.104 143

I get the standard IMAP console.

However, if i try to access the machine using its WAN address or its domain name from either a remote machine or even that machine itself, telnet fails to connect as does my mail checking program.

I have a lot of ports forwarded to this machine, and 143 is one of them, I've checked that 1000 times. If anyone has any idea what causes this problem, I would love to know.
Thanks.

However, if i try to access the machine using its WAN address or its domain name from either a remote machine or even that machine itself, telnet fails to connect as does my mail checking program.
Either your IMAP daemon is not listening for connections on the WAN address, or connections to it are being blocked by a firewall.