I seek clarification about reject_unlisted_recipient and smtpd_reject_unlisted_recipient
If smtpd_reject_unlisted_recipient is enabled, WHEN does this check take place in the scheme of smtpd_*_restrictions? I'm not sure, but it looks like it might happen only if and after a PERMIT in the recipient restrictions? Can someone say for certain if/when/where this check happens? If smtpd_reject_unlisted_recipient is enabled, what effect does adding reject_unlisted_recipient to smtpd_*_restrictions have? Is one or the other ignored? If only using reject_unlisted_recipient, I think it would need to be located in smtpd_*_restrictions before things like permit_mynetworks, otherwise local senders will cause bounces for sending to invalid addresses instead of getting an immediate rejection. Is this right? If smtpd_reject_unlisted_recipient forces the check to happen after a PERMIT (see my first question), that's a better solution for this because otherwise external systems can use it as an address verify service??
