We assume that you have the kind of Internet access which seems to be most common at universities and online services nowadays: You dial into your provider's network using PPP over a serial connection. Your incoming mail is spooled at the provider's POP or IMAP server, while outgoing messages are to be sent via SMTP. You don't have a domain name of your own, so everything has to use one address.
We assume that you have already installed a fairly recent version of Eric Allman's sendmail (version 8.8.8 is current at the time of this writing and should work fine).
This document is partially referring to specific properties of Debian GNU/Linux systems; users of different distributions will have to take some care.
Make sure you have the following information at hand:
The configuration we are planning has two main goals:
To achieve this, we will make use of sendmail's