I currently have my MX records point to Linux box running FC4, sendmail. Rather than use an internal DNS to forward email to my exchange server I use the mailertable function.

This obviously forwards on all my NDR attacks which I want to stop! I have been monitoring the addresses used for NDR and feel I can remove 90% by adding just a few addresses.

Is there anything that I can do on my linux machine before the email is forwarded to my exchange server.

I originally wanted to put something in /etc/alias so that certain emails where sent to /dev/null but get the feeling that this isn't even used.

Anyone got any solutions for this, otherwise I will have to look at sorting this out on the Exchange side