ProxSMTP is a flexible tool that allows you to reject, change or log
email based on arbitrary critera. It accepts SMTP connections and
forwards the SMTP commands and responses to another SMTP server. You
need to be able to write the filtering scripts that integrate it with
your particular needs.

Author:	Nielsen <nielsen at memberwebs.com>
WWW:	http://memberwebs.com/stef/software/proxsmtp/