So, I am setting up a backup mail server.
I got it relaying messages (saving them to queue and then, as soon as primary's up, deliver them to primary). It took following two lines:
relay_domains = $mydestination domain.tld smtpd_recipient_restrictions = permit_mynetworks check_relay_domains
However. I want a secondary not only to relay messages, but also to store them to local mailboxes (provided, the local mailboxes with needed names exist), so I could access them in case of emergency via, say, roundcube webmail.
How do I make Postfix both relay and receive messages at the same time?