A short tutorial on how to modify your postfix confguration so that unknown virtual mail users get rejected before content-filtering. By Athanasios Alexandrides

NOTE: This document is deprecated. Instructions have been incorporated into the tutorial Making Virtual Mail Users in Mac OS X Server

The way Apple has implemented virtual domains creates a few inconsistencies throughout the Mail Service composed of Postfix, Cyrus, SquirrelMail, Mailman, amavisd-new, SpamAssassin and ClamAV. One of them being, that mail for unknown virtual mail users gets accepted to the queue, passed on to the content-filter and only later rejected. While this may seem no big deal, it actually uses up processing power for no good reason.

This document will guide you through solving this issue and is targeted at experienced Mac OS X Server users.