Postifx header_checks not working

I have the main.cf config:

header_checks = regexp:/etc/postfix/header_checks

And the /etc/postfix/header_checks:

/^Subject:.*viagra.*/i DISCARD
/^Subject:.*pills.*/i DISCARD
/^Subject:.*f\*ckbuddy.*/i DISCARD
/^Subject:.*f\*ckfriend.*/i DISCARD
/^Subject:.*f\@ck.*/i DISCARD

/^From:.*viagra.*/i DISCARD

Notice I have added the /i to make case insensitive. Not sure if it allows this?

I have tried sending emails from a hotmail to my server with pills in the subject but still no luck! Also is there a return to sender method instead of DISCARD?

Solution 1:

If postmap -q "<put test header here>" regexp:/etc/postfix/header_checks is correctly returning DISCARD (or the appropriate action for the match) but postfix is not actually performing said action, then there is probably a receive_override_options=no_header_body_checks somewhere in main.cf or master.cf that is turning off the header checks. In the master.cf file, it would be a -o option in one of the service configuration entries.

There are 4 options for receive_override_options:

• no_unknown_recipient_checks Do not try to reject unknown recipients (SMTP server only). This is typically specified AFTER an external content filter.
• no_address_mappings Disable canonical address mapping, virtual alias map expansion, address masquerading, and automatic BCC (blind carbon-copy) recipients. This is typically specified BEFORE an external content filter.
• no_header_body_checks Disable header/body_checks. This is typically specified AFTER an external content filter.
• no_milters Disable Milter (mail filter) applications. This is typically specified AFTER an external content filter.

The no_address_mappings options will typically be located in main.cf while the other options, in master.cf

The "-o receive_override_options" overrides main.cf settings to avoid duplicating work that was already done before the content filter. These options are complementary to the options that are specified in main.cf

Source: Postfix After-Queue Content Filter

Solution 2:

• regex: and pcre: patterns are case-insensitive by default. However, the i flag should work.
• You can use REJECT instead of DISCARD to inform the sender.
• Did you use postmap /etc/postfix/header_checks and reloaded postfix?
• You can test regexes online at many sites. http://www.pagecolumn.com/tool/pregtest.htm allows POSIX regexes.

• If available, using pcre regexes is usually faster then using the Posix implementation with regexp:. Use header_checks = pcre:/etc/postfix/header_checks

• What are the log files saying?

Solution 3:

In the header_checks(5) manual page, there is this paragraph which says that for a while now the default for all regular expressions is to view them as case insensitive:

COMPATIBILITY
      With Postfix version 2.2 and earlier specify "postmap -fq" to query a table that contains case sensitive patterns. By default, regexp: and pcre: patterns are case insensitive.

So adding a flag to your regular expression would not fix your problem.

As others have mentioned, your first step is to verify that it works with a:

postmap -q "<string to test--i.e. Subject: Viagra>" /etc/postfix/header_checks.re

The output is going to be the action for the line. (DISCARD in your case)

If that works, you may be missing the line to include the header or a line that prevents the inclusion as others have mentioned.

header_checks = regexp:/etc/postfix/header_checks.re

Since you say you have that line there, the latter much be the problem.

Note that I have a .re extension. I don't think that matters, but it may be a good idea to have some kind of extension to know what the file contains.