Listed here are a number of header checks that do work but they are ineffective for the most part.  Here is the problem.  When you look at these examples they have a Subject that you are searching for.  As a result you will be writing header checks until the day you die, not good.    My thinking is that you will want to discard ...

Header checks with Postfix can be used to deal with unwanted mail before your server wastes time with it.  Created the file /etc/postfix/header_checks and then add this line in your main.cf. header_checks = pcre:/etc/postfix/header_checks The format line for each header check follows this ...

One way to implement content filtering is to use regular expressions in your header, mime_header, nested_header and  body checks.  This should be simple matches to regular expressions.  The goal with this example is to eliminate non-English characters, since we cannot read them anyway.  This will drop all non-English ...