Postfix Header Checks

[dirk]

Hi,

I've read that Postfix can perform certain actions on emails based on the contents of the email header (header checks). How do I make my Postfix act like that? For example, I want Postfix to delete all emails that have a spam score (from SpamAssassin) of 15 or more. The header of such emails contains a line like this:

X-Spam-Level: ***************

Thanks,

Dirk

[falko]

Here's a small introduction on Postfix header (and body) checks:
http://www.postfix.org/header_checks.5.html

Basically you have to do something like this:

postconf -e 'header_checks = regexp:/etc/postfix/header_checks'

Now create the file /etc/postfix/header_checks and put something like this into it:

/^X-Spam-Level: \*{15,}.*/      DISCARD

DISCARD will delete all messages with a spam score of 15 and above. You can choose another action than DISCARD, they are listed in the link I posted at the beginning.

Finally, restart Postfix:

/etc/init.d/postfix restart

[dirk]

Thanks, Falko.
For the REDIRECT action, I need Postfix 2.1 or above?

Dirk

[falko]

Yes, that's true, the REDIRECT action is new in Postfix 2.1.

[Icaro]

I'm having problems with REDIRECT action in header_checks.
My postfix is version 2.3.8-2+etch1.

In my main.cf I have:

header_checks = regexp:/etc/postfix/header_checks

And the "header_checks" file:

/^To: .*@(?!mydomain\.com>)/ REDIRECT root@mydomain.com

The problem is that the emails are not being redirected, only rejected.
also if I put REJECT "message" instead of REDIRECT the message I put in the REJECT action doesn't appear in the log....so it seems this actions doesn't work well...

Anyone can help me with this?

Thanks in advance and excuse my english.

[falko]

Originally Posted by Icaro

The problem is that the emails are not being redirected, only rejected.

What's in your mail log when this happens?

[Icaro]

Hi Falko, thanks for the reply. This appears in my log:

Mar 12 17:22:51 mail postfix/smtpd[7132]: NOQUEUE: reject: RCPT from cm35140.red.mundo-r.com[213.60.35.140]: 554 5.7.1 <itbsoft@gmail.com>: Relay access denied; from=<printer@mydomain.com> to=<itbsoft@gmail.com> proto=ESMTP helo=<RNPABFF9A>

[Icaro]

Falko, I found the error. The regular expression is not working. The message was rejected due to authentication problems. Once I solved these problems the message is sended so the problem I have now is that my regular expression is not working.

In the log I see lots of messages like this:

Mar 11 16:23:43 mail postfix/cleanup[21225]: warning: regexp map /etc/postfix/header_checks, line 2: Invalid preceding regular expression

And the header_checks file is:

/^From: .*printer@mydomain\.com>/ OK
/^To: .*@(?!mydomain\.com>)/ REDIRECT root@mydomain.com

Do you know what's wrong with this file, I'm trying that printer@mydomain.com can't send emails outside of mydomain.

Thans again.

[sjau]

Hmmmm, I'm also currently looking into that. Is there a way to REJECT all emails in which a given string occurs in any of the headers? This far I can only see examples that check specific headers.

Would this work:

*some_string* REJECT?