OK, thanks, Wietse. I've set up my web hosting service's smarthost as my smtp_fallback_relay (instead of making it my relayhost as before), and I'm trying the following as my smtp_reply_filter:
if !/^5[0-9][0-9][ -]5\.1\.[0-9] / /^5(.*)$/ 4$1 endif which should change any 5xx-series reply code to a 4xx-series code, except it will keep the reply unchanged if there is a 5.1.x (address status error) enhanced status code. Rich Wales [email protected]
