I've been interested in offering customers to train manually train the SpamAssassin Bayes filter for ham and spam (to reduce false positives and negatives). However, I can only find documentation to this for local mailboxes and IMAP. Most users however, retrieve their mail through POP and use Outlook (Express) as mail client. Is there a way to train SpamAssassin with such a setup (e.g. forwarding mail with Outlook (Express) using SMTP)?
Only if you can somehow get the users to forward an un-mangled message, complete with original headers, as an attachment. You can then have a script strip off the attachments and feed those to sa-learn.
The fundamental problem with normal forwarding is that from a SA perspective, the forwarded message looks very little like the original. New headers, different encoding, extra text often added to the body, superflous mime sections dropped, others added.
Since SA learns from the message headers and some of the message encoding has an impact on learning, these changes cause problems..
