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Spoofing Emails to My Own Domain

Dear Experts,

I am facing a problem that someone is spoofing my domain address and sending
emails to my own domain users.

I have set valid SPF, DKIM, DMARC for my Mail server. How can I sort this
problem with postfix to stop this spoofing ?

If I filter emails based on SPF this also block many legitimate email with
spf not set properly.

Bilal Ahmad

Network Administrator

Comments

Re: Spoofing Emails to My Own Domain

By Bastian Blank at 07/10/2019 - 04:21

On Tue, Jul 09, 2019 at 09:25:10PM +0500, <a href="mailto:bilal. ... at kfueit dot edu.pk">bilal. ... at kfueit dot edu.pk</a> wrote:
Envelope sender or header from?

First is "fixed" by SPF. Second is completely normal, just check your
mail sent to this very mailing-list.

Bastian

Re: Spoofing Emails to My Own Domain

By Dominic Raferd at 07/09/2019 - 12:37

On Tue, 9 Jul 2019 at 17:26, <bilal. ... at kfueit dot edu.pk> wrote:
If you use opendkim/opendmarc as milters to postfix then opendmarc
should block emails that spoof your domain (as I see you already have
dmarc setting p=reject). If this is not happening then probably you
have some incorrect settings in opendkim.conf or opendmarc.conf. For
instance, in opendmarc.conf you need 'RejectFailures true'.