Annoying sendmail feature of the day
Why is it, when you've got this spiffy little (undocumented) protocol for chatting between a mailer daemon and a sendmail filter program, that all of the packages I've found with precompiled sendmail filter programs include sendmail as a prerequisite?
Sure, the protocol is undocumented, which means that it's at risk of changing, but you really don't need that dependency. Sure, there aren't any other MTAs that support sendmail filters yet, but postoffice 1.3.x will (the ongoing library is up to a whopping 244 lines, and may bloat to about 500 lines by the time I'm done with it), and the wire protocol is simple (if braindamaged) enough so that it can be reimplemented without too much pain.
It's probably foolish to wonder why these dependencies are there; it's Open Source®™© software, so a certain degree of obfuscation is to be expected (and, lemme tell you, sendmail has been around long enough to be one of the undisputed masters of obfuscated code. The person who decyphered the "milter" wire protocol is a far more patent programmer than I am.)