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Re: filtering non-local aliases with procmail

1999-01-07 21:44:53
At 04:57 08-01-99 +0200, era eriksson wrote:

Generally, by the time your MTA has accepted a spam message, You Have
Already Lost. Procmail can be a good compliment to MTA filters but
they should really be your first and most important line of defense.

Certainly, but if a spammer sends one message addressed to say, 10 users at
this one domain, ONE copy of the message comes in.  But lets say those 10
users are all at different services -- you turn around and pump 10 times as
much data back OUT of your system.  I got two copies of a 3.5MB file
attachment from some bonehead last month (spammed two addresses with a
massive powerpoint presentation) - imagine pumping that through a free
remailer on a thin connection to a dozen or more people...

Yes, you've lost part of the battle if you've already accepted the message,
but if you can kill it right then before forwarding it along, you are much
better off.  Same thing goes for removing spam so someone on a dialup
doesn't have to download it over POP or IMAP (of course, antispam should be
a published policy).

There are various Sendmail hacks available; 8.9.1 comes with a lot of
the antispam stuff turned on by default. A good place to start

Lots of the antispam stuff has to do with securing sendmail from being
abused into a relay.  Generic spamcrap will still flow freely through.


---
 Please DO NOT carbon me on list replies.  I'll get my copy from the list.

 Sean B. Straw / Professional Software Engineering
 Post Box 2395 / San Rafael, CA  94912-2395

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