ANSWER: spam scanning stopped working

[Kurt Yoder]

So when I installed mimedefang, it created an /etc/mail/spamassassin
directory which wasn't there before. Spamassassin looks in this
directory for its rules first *if it exists*. Since
/etc/mail/spamassassin didn't exist before, this wasn't a problem.
When mimedefang created it, it only added a rule for itself, and no
other rules were found.

So my solution was to link /etc/mail/spamassassin to
/etc/spamassassin (on Debian). So now Spamassassin finds its rules
again, and everything's working. Thanks for everyone's help!

--
Kurt Yoder
Sport & Health network administrator