ASSP is a mail proxy, which opens SMTP sessions with mail senders on part 25. If it doesn't like the mail, it refuses to accept it. If it does it opens an SMTP session with qmail, which is on another, deliberately anonymous, port, and passes on the mail. The main purpose of this is to get rid of bounce messages from incoming mail with addresses for which we do not accept mail.
Over the next few weeks, as time allows, I will be turning on some additional filters that should get rid of the most egregious incoming spam at the source.
ASSP also processes outbound mail, adding any address to which you send to a white-list, where it stays for 36 days. So if there is an address from which you want to receive even the worst spam, just send e-mail to them once a month.
Done. Currently in /u/wmcowan/sfw/assp/assp/bin/roll-log.