Quoting from K. Richard Pixley's mail on Mon, Feb 10, 2003 at 10:04:05AM -0800:
Thanks. I'm trying that now, but finding it unsatisfactory. The problem
is that many mailing lists, and certainly most errant human senders,
recognize bounce messages and say to themselves, "Doh! wrong address.
guess I won't use that again." In contrast, mail that is simply dropped
on the floor gets resent, and resent, and resent, and resent...
I really want unknown addresses bounced. If there isn't a well known or
common way to do this now, then I'll prolly start hacking.
You will also have to remove 550 (or whatever your smtp server uses
for unknown user) from the antispam option for the bounces to be sent.
--
Sunil Shetye.