I too would be interested in the question about "abnormal amount of emails to postmaster". We get about 15K a day of these and just recently started to pipe them into /dev/null. It is more of a burden to delete them manually. Anyone else have high postmaster email counts?
I'll bet you're both using Sendmail and have Mailer-Daemon aliased to postmaster. If so, change the Mailer-Daemon alias to /dev/null That should eliminate the various bounce messages without stopping anything that is actually addressed to postmaster.
(One of the things I like about Exim is that it doesn't use Mailer- Daemon; and the default handling of undeliverable bounce messages is much more sane.)
-Pat
