SpugSpam - a Spam Solution for UNIX Freaks
SpugSpam is a script that runs a confirm-response spam filter. It is designed to be flexible, and intended for use within your procmail pipeline. It is not intended to be user friendly, so if you are asking yourself "what's a procmail pipeline?" then SpugSpam is probably not for you.
Revision 1.2* supports SPF checking, the basic confirmation engine, rule based pre-filtering and (limited) remote management through e-mail. It will most likely take you a few hours to set up, but if you're looking for this sort of thing, it's probably worth it.
You'll need the PySPF package to take advantage of the SPF support in versions 1.1 and above (please use this - lots of spammers use authentic e-mail addresses and the owners of those addresses don't deserve confirmation messages if the message comes from a sender that isn't authorized by their SPF record).
For a similar project, see ASK - The Active Spam Killer. This is a much more user friendly solution than SpugSpam.