Yes, I know this. I actually wrote something to create a RBL based on virus senders. I'd just like to be able to drop (or maybe teergrube) the connection in the BEGINNING instead of after the hangup.
Look into the sendmail config option BAD_RCPT_THROTTLE. The value is the max number of allowed invalid recipients after which sendmail starts delaying responses to sender. (Basically after each RCPT it sleeps before sending "user unknown.")
Unfortunately the delay is (was) hardcoded to 1 second, but it'll at least slow them down a little.
-- Kelson Vibber SpeedGate Communications <www.speed.net>
