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).
Added change submitted by Sam Lantinga allowing multiple "remote:" patterns in the recvdpat file.
Changed "sender" and "deliver" scripts to use their own mini-shell language to avert a security hole caused by expanding e-mail addresses into shell scripts.
Fixed bug causing traceback during --show-pending for messages with no subject.
Fixed incompatibility with older python versions during --show-msg (was using os.path.sep, which is a newer feature)
Added SPF support.
fixed order dependencies in subject headers
For a similar project, see ASK - The Active Spam Killer. This is a much more user friendly solution than SpugSpam.