On Thu, 7 Oct 2004 11:53:32 -0400, Dan Barker wrote
You will connect to the 'net via your cellphone, a dial-up, or a wireless
network. Most likely, the ISP won't route port 25 traffic to your "home"
system's SMTP servers, so you must use the remote ISP's SMTP
servers. They have no idea who you are, and your home server has no
idea from where you might connect.
Configure your home server to use SMTP AUTH, preferably on the "submission"
port (which other ISPs shouldn't block.) Then you can send using your home
server from anywhere.