Spamassassin postfix authenticated users

Revision as of 21:25, 28 September 2009 by SeanG (talk | contribs)

Howdy, Here's a little How-To I wrote up after not being able to find a way of whitelisting authenticated users in spamassassin.

Please note that this configuration will need reviewing EACH and EVERY Upgrade of zimbra that you do, as not all settings will carry over.

Feel free to drop me a a line, or update this article, This example was written and tested on Zimbra NE 5.0.6


All of the following should be done as the user zimbra

Postfix Changes

Enable Auth User Header

This enables a header on all authenticated emails that shows who authenticated to send the email.

Received: from [0.0.0.0] (unknown [192.168.255.4])
	(Authenticated sender: myemail@mydomain.com)
	by smtp.mydomain.com (Postfix) with ESMTP id 08333374399
	for <geekygeeks@gmail.com>; Tue, 28 Oct 2008 10:45:37 -0400 (EDT)

Edit your zmmta.cf file, in /opt/zimbra/conf/ on your MTA Find the section that starts with: SECTION mta DEPENDS amavis

Right before the end of this section, and the line that says RESTART mta Add the line:

  POSTCONF smtpd_sasl_authenticated_header          yes 

Change the Header to not leak Usernames

This header leaks the user's login to whomever is sent an email, to change this we should rewrite that header to something we can match later from spamassassin, such as:

Received: from [127.0.0.1] (localhost [127.0.0.1]) by Authenticated User (smtp.mydomain.com) with ESMTP id BA7D13744DB

To do this, we need to edit /opt/zimbra/conf/postfix_header_checks

And add the Regex to match & rewrite.

/^Received: from (.* \([-._[:alnum:]]+ \[[.[:digit:]]{7,15}\]\)).*\(Authenticated sender: ([^)]+)\).*by \
(smtp\.mydomain\.com\) \(([^)]+)\) with (E?SMTPS?A?) id ([A-F[:digit:]]+).*/  REPLACE Received: from [127.0.0.1] \
(localhost [127.0.0.1]) by Authenticated User (smtp.mydomain.com) with $5 id $6

And Reload Postfix

postfix reload

SpamAssassin Changes

Now we need to create a rule, and give it a negative score, in order to lower all authenticated senders messages (but not whitelist!)

Create the Rule

Create and edit a new rule, in this example I will use /opt/zimbra/conf/spamassassin/20_user_auth.cf

Add the following lines to this file

# This is a spamassasin ruleset that gives a much lower spam rating for authenticated users
#
header LOCAL_AUTH_RCVD    Received =~  /Authenticated User \(smtp.mydomain.com\).* /

Add a Score to your new rule

In this example, I lower all authenticated senders spam scores by 8.

Edit /opt/zimbra/conf/spamassassin/50_scores.cf

Add the Line:
score LOCAL_AUTH_RCVD -8 -8 -8 -8

Restart Amavis

zmamavisctl restart

The Source

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