Postfix route unknown users (ONLY!) to default address

Question

I use postfix and would like to route all emails which are NOT configured to got to a fallback address. Is that possible? So e.g.

john@email.com -> configured in virtual file and is read by user account john bill@email.com -> is NOT configured as a user and has no entry in the virtual table -> should be added to the mail box: unknown_users@email.com

Thanks in advance

Leon

Answer 1

The answer is different for local and virtual addresses.

For local addresses, you can use luser_relay; this takes a single fallback address.

For virtual addresses, use virtual_alias_maps to add wildcards per recipient domain.

I should warn you that using catchalls is not recommended, as you cannot properly reject mail; in fact, you will never reject any mail with such a setup, and bouncing them later will produce backscatter spam (and gets you blacklisted PDQ.)