Hi, basicly my ISP blocks port 25 but I want to send out email using my Red Hat 9 server. I know I have sendmail installed and I updated it via Up2Date but I want to change the SMTP port from 25 to anything else. Preferanbly, I would like to use Port 2525 since it is easy to remember. Any ideas how to do this?
Also, if this helps then I think I have sendmail.cf installed also.

Open up /etc/sendmail.cf
Find the line
O DaemonPortOptions=Port=smtp,Addr=127.0.0.1, Name=MTA

and change Port=smtp to Port=2525

You probably need to change Addr to your external IP too.

thanks for the reply. I have a follow up question: Where it says Addr, I have a dynamic IP so I have a hostname (mosherben.dyndns.org) so should I change it to this?

Does it work using 127.0.0.1? If not, then yeah you should probably use the domain name.

Any chance there is a similar way to configure Postfix to send mail over a different port as well?
I'm having major trouble getting mail to go out from Sendmail and Postfix, only recently I
managed to get mail between users on the system itself to start working. (except for root.
sending works for this account, but receiving doesn't.)
I'm quite new at configuring a mailserver but eager to learn. my ISP conveniantly blocked
the SMTP port, leaving me without the possibility to use the mailserver on my domain on
the internet, which is quite annoying.. I have mailing lists to maintain!