PMDF System Manager's Guide

On an e-mail firewall, the issue of postmaster mail can need a bit of extra consideration.

Domain names visible on the Internet are required to be able to accept mail addressed to postmaster@domain. PMDF itself will send warning messages and, (by default), copies of users' bounce messages to the postmaster.

It is critical that the postmaster address be a valid address for receiving mail. The normal recommendation for postmaster mail, therefore, is that it be directed to a local account (in the PMDF sense, i.e., delivered via the local channel) on the PMDF system itself. However, for an e-mail firewall it is possible that you will not want to have to have someone log on regularly to the e-mail firewall to check postmaster mail. If you do want mail to a different system, be sure to ensure that the connection between the e-mail firewall system and that other system is a very reliable connection; and be prepared that if something happens to break that connection, you will want to immediately change the postmaster address on the e-mail firewall to some other functioning address or be prepared for the potential for serious e-mail problems. (Bouncing postmaster mail is not pretty.)