I have just installed Postfix for the mailer on my Linux 9 installation. I can telnet into port 25 fine. However, I cannot telnet into port 110. What could be wrong? I do NOT have a firewall running.

Port 110 is for pop3 (post office protocol). That's an entirely different cup o tea than postfix. Postfix is just an alternative client to sendmail which uses SMTP (server message transfer protocol) to deliver/receive it's mail (uses port 25 by default). So you did nothing wrong...there isn't really a problem at all. You're all set to config it! :mrgreen: