[exim] Caching Spammers to Speed Processing

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Author: Marc Perkel
Date:  
To: Exim Users Mailing List
Subject: [exim] Caching Spammers to Speed Processing
Just wondering if anyone else is doing this trick. Here's what I'm
experimenting with.

As you all know - running messages through Spam Assassin is a lot of
system load. So - if that can be avoided - mail can be processed faster.

So I've been thinking about temporary black lists that are triggered by
the sins of spammers - but cleared out every hour or so. For example - a
spammer sends a high scoring spam to 3 or more people in a single
connection. The spammer keeps coming back trying to dictionary attack me
and I have to process this same spam over and over.

I do front end spam filtering for other people and recipient veryify
doesn't always work.

So - my idea.

After the first spam to 3 or more people I add the IP address of the
host to a list. That list returns DEFER when the host reconnects to send
more spam. Every hour - I empty the list. The idea being that just in
cast there are non-spammers on that host then they only get delayed an
hour rather than rejected.

Same idea for verifying senders. If a sender email address fails
verification and a spammer is hitting me over and over with the same bad
email address - then why do a callback EVERY time? Instead - I put that
email in a list and that from address is blocked.

Again - th list lives only one hour - to keep it from growing into a
HUGE list. The idea being - reducing system load and reducing callbacks
and spam assassin loads.

So - anyone have any thoughts on this idea? And interest? So far the
code to do this is really simple.

--
Marc Perkel - marc@???

Spam Filter: http://www.junkemailfilter.com
    My Blog: http://marc.perkel.com
My Religion: http://www.churchofreality.org
~ "If it's real - we believe in it!" ~