[pfx] Re: How to use two LMTP deliveries simultaneously?

[Viktor Dukhovni via Postfix-users]

On Sun, Feb 08, 2026 at 10:25:14AM -0500, Wietse Venema via Postfix-users wrote:

> PROBLEM: your server will accept spam for recipients that do not
> exist in enfer-du-nord.net. Later it discovers that the recipient
> does not exist, and returns that spam to someone who did not send
> the spam. Your server may end up being denylisted for beong a
> backscatter source.
> 
> Insteead, use recipient_bcc_maps.

Well, actually, I am impressed that the OP considered virtual
alias_maps, that would also be my approach.  However, not as a PCRE
wildcard rewrite, but rather as a per-recipient rewrite for each user.

    user1@foo.example   user1@foo.example, us...@db.foo.example
    user2@foo.example   user2@foo.example, us...@db.foo.example
    ...

Or if the input domain is already a virtual alias domain, different
from the underlying mailbox domain (which the server might not
accept from external clients):

    user1@foo.example   user1@virtual.invalid, user1@db.virtual.invalid
    user2@foo.example   user2@virtual.invalid, user2@db.virtual.invalid
    ...

With transport mappints for "virtual.invalid" and "db.virtual.invalid".
Of course with an existing mailstore the above would need additional
aliases of the "@virtual.invalid" form for each underlying mailbox.
I always start with that, but it should be possible as a retrofit.

One can do clever things with per-recipient regex BCC rewrites, but
those can be tricky to get right.

-- 
    Viktor.  🇺🇦 Слава Україні!
_______________________________________________
Postfix-users mailing list -- postfix-users@postfix.org
To unsubscribe send an email to postfix-users-le...@postfix.org