About a week ago, I noticed e-mail was not being delivered. At first, I thought this was a sendmail config problem, thinking maybe something didn't restart correctly when the White Dragon rebooted. After several very unsucessful atempts to get what seemed something very simple, I decided to abandon sendmail, and try an other e-mail server.
So, we installed Mercury again-- our trusty e-mail server of old. It didn't work either. At this point, I was confused. Then, a thought dawned on me, I check on our ISP's site, and my suspicions were confirmed. Due to the most recent set of viruses-- SPAM sending viruses, our ISP firewalled outgoing connections to port 25. Unfortunately, I don't think we can remove this block despite the fact we are not your typical brain-dead user that wouldn't notice something like a SPAM virus.
To get around this, we set up a mail relay on a diffrent port on a remote computer. It's setup to only accept connections from our network and relay anything we send it. Then, our server here was modified to use that relay when sending mail.
It's kind of a long route for getting e-mail out, but it works. It's too bad most people are too stupid to be trusted with an unfirewalled internet connection-- makes things harder for those of us who can.