Personal SMTP

[paul wheaton]

Every time I move my computer, I end up needing to find a new SMTP server or use yahoo
mail.
It seems that the primary function of an SMTP server is to accept the mail you are trying
to send and then forward it to the recipients SMTP server - if there are any problems, it
will try again later.
Why not have something like that built into a mail program? Or even have something like
that running in the background? Whenever your computer is on and connected, it could be
doing its thing.

[David Weitzman]

There isn't really a good reason for people not to run their own outgoing SMTP servers, although I can think of two possible explanations:
1) ISP's want to control your life. You're easier to track if you use someone else's outgoing server.
2) Imagine the evil if even one in every hundred mail users had open relays on their computer (but yes, this would be prevented if mail programs connected to the receiving server directly without a local SMTP server running).
I actually wrote an extremely simple outgoing SMTP server once to tinker with DNSJava (and I intend to write a more complete one sometime soon as part of my mail server project). I remember thinking at the time how stupid it was to stick an ISP in the middle of outgoing transactions. Unless there's something about accessing and using MX records I don't understand, it's still stupid.

[Frank Carver]

I use a small Linux distribution ( http://www.e-smith.org/ ) running on an otherwise unused PC for this. It not only works as a great firewall, gateway and web cache for my other machines, but also includes a direct-distribution SMTP router.
I think it's only Windows machines which typically need an external SMTP router.