Found by talking SMTP to port 25 of the test server once it answered
again (2026-10-10): RCPT TO:<dmarc-reports+bs.mixdep.ru@selfpost.mixfed.ru>
was refused with "550 5.1.1 User unknown in relay recipient table".
With INBOUND_RELAY_ENABLE and DMARC_REPORTS_ENABLE both true the server's
own name is a relay domain (for the reports) and relay_recipient_maps
lists the relay's recipients only. smtpd_reject_unlisted_recipient
applies after the restriction list, so the OK that
check_recipient_access gives a report address does not help: every
report was refused. The table of report addresses is added to
relay_recipient_maps in that combination.
Checked on the server by setting the parameter in the running container
and reloading Postfix: the domain's report address is answered 250, the
former server-wide mailbox and an unknown local part 550, a foreign
domain and an inbound domain without recipients 554. e2e: the combined
case requires relay_recipient_maps to name both tables.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>