OSEC

Neohapsis is currently accepting applications for employment. For more information, please visit our website www.neohapsis.com or email hr@neohapsis.com
 
Subject: Re: Spam Deferred Trick
From: Ralf Hildebrandt (news-list.postfix.usersinnominate.de)
Date: Wed Oct 11 2000 - 07:21:24 CDT

On 11 Oct 2000 13:52:31 +0200, Big Brother <adminclouddancer.com> wrote:

>What I see is an incoming message for an non-existant user. Postfix
>generates a bounce message to the sending host.

Why don't you reject mail for non-existant users directly at the SMTP port
via local_recipient_maps ?

> That sending host
>terminates the connection for the bounce message (spam software most
>likely), postfix kicks it into the deferred queue to try, try again.

The bounce is sent to the MX that handles mail for the envelope sender
address, not to the originating server!

>The other minor note is an external host .forward to a local
>non-existant user, the bounce message just goes into a mail loop. I
>didn't find a message thread on adding a header field to detect this
>(as in procmail).

local_recipient_maps is your friend 

-- 
ralf.hildebrandtinnominate.de
Dipl.-Informatiker                                       innominate AG
system engineer                                      networking people
tel: +49.30.308806-62  fax: -77   http://innominate.de  pgp at request