[Mimedefang] Rejecting spam - users unsubscribed from distribution lists

[Ingeborg Hellemo]

I need some advice. We are a small university running Mimedefang with 
SpamAssassin and greylisting.

For the last couple og months we have been rejecting spam with a 
SpamAssassin-score over 15 with the error message "554 5.7.1 Spam-score 
(16.887) too high".

The problem we have recently discovered is that some distribution lists allows 
high scoring spam to be sent out. It then gets rejected by our mailserver and 
our users get unsubscribed from the lists as if we had returned "User unknown".

I'm not very fond of silently dropping high scoring spam on the floor since 
any "real" senders will not be notified of their message not getting through.

How do you handle this?


--Ingeborg
-- 
Ingeborg Østrem Hellemo  --  ingeborg at cc.uit.no  (Univ. of Tromsø, Norway)