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From: Eero Volotinen on 26 Oct 2009 15:15
I am running ssl+sasl authenticated mailgateway and problem is that in
some cases clients from world are sending mail from "blacklisted" networks.

The main problem is that spamassasin is analyzing received headers and
it might tag message as spam by received by headers.

So, How I can remove headers only from outgoing mail using:
http://www.posluns.com/guides/hedrem.html


--
Eero

From: Magnus =?iso-8859-1?Q?B=E4ck?= on 26 Oct 2009 15:27
On Monday, October 26, 2009 at 20:15 CET,
Eero Volotinen <eero.volotinen(a)iki.fi> wrote:

> I am running ssl+sasl authenticated mailgateway and problem is that
> in some cases clients from world are sending mail from "blacklisted"
> networks.
>
> The main problem is that spamassasin is analyzing received headers
> and it might tag message as spam by received by headers.
>
> So, How I can remove headers only from outgoing mail using:
> http://www.posluns.com/guides/hedrem.html

Yes, header_checks can be used. Howeer, you'd want to avoid doing this
to all email. To affect only messages submitted by your clients, define
two cleanup(8) services (one with these header checks and one without)
and use separate SMTP listener for your SASL clients (which you might
have already).

http://www.postfix.org/postconf.5.html#cleanup_service_name

--
Magnus B�ck
magnus(a)dsek.lth.se

From: Eero Volotinen on 26 Oct 2009 15:39

> Yes, header_checks can be used. Howeer, you'd want to avoid doing this
> to all email. To affect only messages submitted by your clients, define
> two cleanup(8) services (one with these header checks and one without)
> and use separate SMTP listener for your SASL clients (which you might
> have already).
>
> http://www.postfix.org/postconf.5.html#cleanup_service_name
>

Looks like some other people are also tackling with almost same problems:
http://www.irbs.net/internet/postfix/0706/0131.html

--
Eero

From: Noel Jones on 26 Oct 2009 15:43
On 10/26/2009 2:15 PM, Eero Volotinen wrote:
> I am running ssl+sasl authenticated mailgateway and problem is that in
> some cases clients from world are sending mail from "blacklisted" networks.
>
> The main problem is that spamassasin is analyzing received headers and
> it might tag message as spam by received by headers.

I don't think SA does that by default, but some admins do
unreasonable things. A nearby university rejects mail with a
blacklisted IP anywhere in the headers, event the Subject!! A
local government department adds spam points to mail with no
Received: headers, or with a RFC1918 IP somewhere in the
headers. (of course, they're the same guys who until recently
choked on DKIM signatures.) You just can't win sometimes...

set in main.cf:
smtpd_sasl_authenticated_header = yes

and use a header check something like:
(all one line, beware wrapping)
/^Received: (.*by myserver.example.com \(Postfix\) with
ESMTPS?A id.*)$/ REPLACE X-Submission: $1

Or better, to just rewrite the header on outgoing mail, use
the above rule in smtp_header_checks rather than header_checks.


-- Noel Jones

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