We have our postfix configured to handle mail for our websites. For every website we have configured a bounce handling user with
local_recipient_maps = hash:/etc/postfix/recipient_maps
The file recipient_maps looks like:
site1_bounce@our-domain.com site1_bounce/
site2_bounce@our-domain.com site2_bounce/
...
We're using lmtp for postfix to communicate with dovecot with local delivery:
local_transport = lmtp:unix:private/lmtp-dovecot
When one of our websites sends mail it uses the postfix VERP feature by using the senmail command options
/usr/sbin/sendmail -XV -t -i
All of this works nicely, and we're getting bounces in different IMAP folders.
By checking the reputation of our mail server I stumbled over one RBL that black lists our mail server, http://v4bl.org. If I understand the informations correctly the reason for this is because we fail 1 test that can be checked out here
http://multirbl.valli.org/fcrdns-test/
If I choose "test by sending an email" I'm getting 1 error, namely, the test program tries to send an email to our envelope RCPT TO address, that is e.g.
site1_bounce+testuser=testdomain.tld@our-domain.com
which obviously fails because we don't have a local mail account for every generated VERP address.
One real world case would be that a recipient mail server accepts a mail from our postfix and sends a bounce mail later to the RCPT TO address.
So how do we map those VERP addresses back to our bounce handling mail accounts? We tried our luck with
alias_maps = regexp:/etc/postfix/verp_alias_maps
with verp_alias_maps being:
/^site1_bounce\+.+@our-domain.com/ site1_bounce
/^site2_bounce\+.+@our-domain.com/ site2_bounce
...
but it appears as postfix ignores our ailas_maps file.
