Milter-regex is a sendmail milter plugin that allows to reject mail
based on regular expressions matching SMTP envelope parameters and
mail headers and body.

In order to build milter-regex, sendmail needs to be compiled with
milter support, installing the libmilter library.

This is the default for the sendmail in the base system.
Some of the sendmail ports omit libmilter by default (SENDMAIL_WITHOUT_MILTER).

This program is developed on OpenBSD by the maintainer.

WWW:  http://www.benzedrine.cx/milter-regex.html