Hi,
Reading the postconf explanation of reject_unknown_recipient_domain and
reject_unknown_sender_domain, I'm having trouble understanding where
these find their use.
For incoming mail: The first test criteria for both is that Postfix not
be the final destination for the recipient/sender domain, so when
Postfix is not set up with a catchall and rejects unknown users, am I
correct to think there is no use for these here?
Likewise for outgoing messages: The criteria for the domain needing to
have valid, well formed MX -- even without reject_unknown_sender_domain,
Postfix won't be able to send such mail anyway. Is this a matter of
instantaneous rejection vs. queue and bounce after retries?
Are these two settings more applicable to relay scenarios?
