May I just point out, it won't be the best of thing to run a mail server from home, especially an SMTP server since Dynamic IP addresses are all gathered into a "Do Not Accept" list that is a part of the Spamhaus project. Add in the fact that many residential ISPs charge an arm and a leg for Static IPs and tend to be a pain in the butt when it comes down to setting up the line for a mail server, you're better off finding a free mail service or using the x10Histing servers for your mail, or finding a mail relay service. What you're asking for is something that would normally come with expensive business circuits.
Most recently, Verizon Communications blocked outgoing SMTP traffic on port 25 to all of their residential/Dynamic IP customers. I was one of the people who were affected by this as the port was blocked last night throughout my area. I had to change every mail account I had in Windows Mail to an alternate port for each account with SSL, and I'm currently in the process of setting up my honeypots to send mail to the various spam databases I contriulbute to using different ports. PITA if you tell me :/