1. watch log for pop/imap auth, notify Postfix to allow relay Spam prevention requires preventing open relaying through email servers. However, legitimate users want to be able to relay. If legitimate users always stayed in one spot, they'd be easy to describe to the daemon. However, what with roving laptops, logins from home, etc., legitimate users refuse to stay in one spot. pop-before-smtp watches the mail log, looking for successful pop/imap logins, and posts the originating IP address into a database which can be checked by Postfix, to allow relaying for people who have recently downloaded their email. Contrary to other similar tools pop-before-smtp needs no hacking in the mail daemons. On the other hand it requires the pop3/imap daemons to run on the same machine as pop-before-smtp and postfix. From Debian 3.0r0 APT