We run some rules in Sendmail and Mimedefang that cause rejection
before Mimedefang would run the SpamAssassin library against the
messages.
In the order the rules get hit, rejection counts from yesterday:
29,148 messages : Host sending mail was in our local blocklist
note below *
42,132 -------- : Sender domain unknown
done by Sendmail, standard ruleset
46,037 -------- : Sender address was a user unknown @columbia.edu
done by Sendmail, local ruleset
1,222,373 -------- : RBL, host sending mail was in Spamhaus
done by Mimedefang
44,091 -------- : RBL, URI in text was in Spamhaus
done by Mimedefang, local code
60,178 -------- : SpamAssassin score was 8.0 or higher
includes some local rules
I know the RBLs would be done by SpamAssassin in many installations.
We found it more efficient to knock off the low-hanging fruit first,
and then run SpamAssassin on what's left.
(* Currently done as sendmail access.db, to be converted to an RBL
to be checked by Mimedefang. Based on spam reports from our users.)
Joseph Brennan
Columbia University Information Technology
