I’m having all sorts of fun playing around with Linux these days, both on my personal systems and on servers. Earlier, I had to configure Sendmail to receive outside mail. I’ve used larger mail solutions on Linux before, such as Qmail, but I didn’t need anything near that complex since I just needed to make sure that this server could receive specifically routed messages.
When I first started digging around, I couldn’t even find out how to change any of the settings, but it was clear that the server was only listening on the localhost loopback address. Even my usual solution of googling for answers wasn’t turning up much. Finally, after searching for about half an hour, I found this extremely helpful guide, which I will simply direct you to if you wish to get Sendmail configured on your box.