OT Sendmail

[Peter Nitschke]

Slightly off-topic.

Some twonk has started using randomly generated email addresses based on a
domain that I host as the return address for a massive spamming session.
I am getting hammered with rejection noticed from msn, yahoo etc

Is there a way for sendmail to block these rejection notices outright?
 I tried adding   mailer-daemon@*  REJECT to the /etc/mail/access to no
avail.

I can kill them with MS, but would prefer to block them before they even
get that far to save bandwidth and CPU on the mail server.

Thanks in advance for any help on this one.

Peter