Filtering mails with specific "From:" headers

[Francois Goudal]

Hi,

I have a postfix mail server, with a spam assassin.
I have some spam that is not detected by spamassassin which is then
delivered to the user's mailboxes.

I noticed that most of that spam has a From: which matches our domain
name (for example, sometimes, I get a mail to me, "that comes from me")

Let's say in the examples that our domain is @foo.bar

This mail server is the destination for @foo.bar messages. All users
that have a @foo.bar address also use this server as an SMTP for their
outgoing mail servers, using authenticated SMTP.

So, when a user @foo.bar is sending an email, it is authenticated on
that server.

This means that any email that is relayed to this server using
non-authenticated SMTP with a From being @foo.bar is not legit.
Do I have a way to specify a rule in postfix to filter our these emails
? (with a From: @foo.bar in a non-authenticated SMTP session)

Best regards.

[Martin Gregorie]

On Thu, 28 Jun 2012 16:10:33 +0200, Francois Goudal wrote:

> Hi,
>
> I have a postfix mail server, with a spam assassin.
> I have some spam that is not detected by spamassassin which is then
> delivered to the user's mailboxes.
>
> I noticed that most of that spam has a From: which matches our domain
> name (for example, sometimes, I get a mail to me, "that comes from me")
>

Make sure that your 'trusted_networks' are set correctly.


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martin@ | Martin Gregorie
gregorie. | Essex, UK
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