It's a DHCP IP, but its always the same anyways. Alright, I'll get a domain. But what's an MX record?

An MX recors is a Mail eXchange record stored on a DNS server that tells an SMTP server where to deliver mail.

Uhuh. So how do I make my email server work once I have a domain? And where can I get one without running into old dot-coms trying to sell me one. The internet's open to everyone, and that means a jobless 14-year old like me should be able to get a domain somewhere.

For information about configuring sendmail:
http://www.sendmail.org/
http://www.tldp.org

None of this post is really new in the thread. Just a reiteration, restatement.

Likely you already have a FQDN (fully qualified domain name) even if you just know your public IP. Try "nslookup <public ip>. You will probably get a line that has a name=<something>. The <something> is of course the FQDN. Put that in the local-host-names file and you should be able to send mail from the outside world to yourself the user@something.

Again, http://www.dyndns.org/ works great. I had a mail server at home which most locations could find using a dynamic IP and the dyndns update service. Now I have a static IP (and an alternative MX), which of course is nicer.

The effort is worth it. It is nice getting mail at home without resorting to an ISP holding (and archiving) it.