Am 27.08.2012 13:17, schrieb Jan Geep: > Good evening, > > I was wonder if there is someone who could help point me in the right > direction so I can solve a spam problem I have. > > I am running a mail server with Ubuntu + Postfix + Maia Mailguard + > Dovecot, all has been working well until recently people have started > receiving spam email that appear to be sent from my domain. > > For example > > From: myn...@example.com > To: myn...@example.com > Subject: Fwd: Re: Scan from a Hewlett-Packard ScanJet 1234 > > But the return path is along the lines of: > > Return-Path: <somen...@spammer.com> > > (see header and main.cf for mail servers below for more information) > > Would any one have any suggestions as the best way to block these type > of emails. Some information that might be important, some of our users > work remotely and so can connect into the gateway running Dovecot and > receive (imaps) / send (smtp) (authenticated) from any location in the > world, I am not sure if this makes it harder to block the spam.
you must not block this because from-headers are not relevant for the smtp-protocol, relevant is envelope (return-path) it is valid to have such from headers and happens really often in confirmation-mails, sometimes in list-sofwtare etc.
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