smtpd_CLIENT_restrictions= reject_unknown_reverse_client_hostname <- applies to everyone check_RECIPIENT_access hash:/etc/postfix/unknown_client_override reject_unknown_client_hostname <- applies to those not in the fileYes, that will work, as long as you keep the default "smtpd_delay_reject = yes".
Too cool. Postfix rocks**2 Thanks Noel Homer Smith CEO Lightlink Internet.