postfix-users April 2010 archive
Main Archive Page > Month Archives  > postfix-users archives
postfix-users: Bounces resulting from forwarded Mails

Bounces resulting from forwarded Mails

From: Michael Weissenbacher <mw_at_nospam>
Date: Wed Apr 07 2010 - 09:29:02 GMT
To: Postfix users <postfix-users@postfix.org>

Hi List!
I am having the problem that our Postfix Mail Server generates too many
bounces which unfortunately results in getting listed (at least at
backscatterer.org). Having digged deepter into the problem i already
read and followed [1] as well as the obvious stuff like correct
local_recipient_maps. The problem i now have is like the following:
- our server accepts mail for localuser@localdomain.com
- there is a entry in /etc/postfix/virtual that forwards this mail to
foreignuser@foreigndomain.com (which is a legitemate destination and
usually accepts mails without a problem)
- the foreign server detects spam or a virus and rejects the delivery, i
get an entry in mail.log like:
  status=bounced (host email.foreigndomain.com[1.2.3.4] said: 554 mail
server rejected message: spam or virus detected (#5.3.0) (in reply to
end of DATA command)
- our server of course then generates a bounce to a fake sender which
either fails because the sender doesn't exist or it triggers some spam trap

I've basically got 2 solutions in mind but i'm unsure on how to
implement them (or if they even make sense):
- It it possible to not generate bounces which go to external
destinations at all. Can i define anywhere that bounces may only go to
known local users?
- It it possible to send the bounces (or only external bounces) via an
alternate relayhost. That way i would prevent that our main smtp host's
ip is getting listed.

tia,
Michael

[1] http://www.postfix.org/BACKSCATTER_README.html