Noel Jones:
We use the built-in feature for this: http://www.postfix.org/postconf.5.html#smtpd_reject_footer
Aha, good point
It's a really nice idea, but in practice few people ever use the contact or correction info provided in a reject message -- some end-user mail programs seem to go to great effort to hide potentially helpful info from the user, so a lot of people never see it. A couple times a year someone actually uses our online contact form, seldom enough that I'm always surprised. But it makes me feel better to know it's always there, waiting to help some poor soul.
mostly I don't look at MX but on dedicated submission points... Andreas
