Hello Fabian, not answering your question and not solving you problem, but after your introduction I feel compelled to say:
[email protected] (Fabian Müller), 2020.08.16 (Sun) 02:15 (CEST): > 1. take e-mails on port 25, check via mysql if it's for a domain it is > responsible for and then forward via lmtp to dovecot which then takes > care of everything else (including rejecting unknown users). I'd recommend to deny delivery right at the front door, i.e. let OpenSMTPd do the rejection. That way the sender gets the Non-Delivery-Notification from her/his own mail server. Otherwise the sending server sees the "250 2.0.0 XXYYZZ Message accepted for delivery" and thinks all is well. Later, when dovecot rejects, your server has to send the NDN, possibly to a spammer, which might bounce and all of that. Marcus
