Using watermark to fight spam backscatter

Rose, Bobby brose at
Thu Apr 3 13:17:27 IST 2008

Are you using the vbounce plugin in SpamAssassin?  It has rules for that
kind of stuff. 

-----Original Message-----
From: mailscanner-bounces at
[mailto:mailscanner-bounces at] On Behalf Of Edward
Sent: Thursday, April 03, 2008 8:06 AM
To: MailScanner discussion
Subject: Using watermark to fight spam backscatter


More and more of our users are receiving large quantities of spam
backscatter. One received 200 messages this week. 

I've been investigating various options (Postfix rules:, BATV: but the
easiest to implement seems to be MailScanner's watermarking, especially
as my system already uses watermarking (we have a postfix + mailscanner
gateway in front of a cPanel exim + mailscanner box).

Watermarking is already successfully implemented and working properly
between the two machines. I've altered this setting for testing:

Treat Invalid Watermarks With No Sender as Spam = 0.1

But after changing this and checking the incoming mail I've noticed a
lot of backscatter doesn't come with From: <> but rather real e-mail
addresses (e.g. MAILER-DAEMON at Is this the right
area to be looking in? Could this be modified, or should I be using some
other feature to help cut down on this?


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