Different userdb per inet_listener

Hello,

we are running Dovecot (2.3.4.1-5+deb10u6) with PostgreSQL passdb and userdb and for remote Postfix:

auth_mechanisms = plain login inet_listener { address = 127.0.0.1 port = 12345 }

It works perfectly.

Now we would like to disable authentication for Postfix (SMTP), but allow it for Dovecot (IMAP & POP3). Something like "receive-only".

Is there any way we can configure different passdb for mentioned inet_listener?

Or is there any variable with "auth requetor name" we can use in SQL query to differentiate the result?

Regards Miloslav