On Fri, Mar 05, 2021 at 03:41:06AM -0500, Steve Dondley wrote:
> Here are postfix config file: https://pastebin.com/bZxjHF5y
I don't usually go chasing pastebin URLs...
> Hopefully something jumps out at you.
There are only two common ways a message without duplicated recipients
gets delivered to the same mailbox twice:
1. Address rewriting (including BCC maps) duplicates a recipient,
and "enable_original_recipient" is not set to "no".
2. A message with multiple recipients is delivered via multiple
transport:nexthop combinations, the separate messages then
get augmented with (or rewritten to) a common recipient.
A third less common way is via local(8) aliases, because local
delivery splits the envelope to one recipient at a time before
alias(5) expansion.
I don't recommend use of local aliases for anything other than
":include:" or "|command" support. Do all ordinary address -> address
rewriting via virtual aliases instead.
Either or both may be happening in your case, and your job is to
find out which.
The first is easy, make sure "enable_original_recipient = no".
The second can happen if your "content_filter" does not specify an
explicit fixed nexthop. Normally, that would be something like:
scan:[127.0.0.1]:10024
but if for some reason your content filter is just a transport name,
then implicitly the "nexthop" is the recipient domain, and recipients in
different domains are delivered separately (creating multiple copies of
the message into the filter).
So long as the envelope is not split, and within a single envelope
address duplication is suppressed, delivery will not be duplicated by
Postfix if not already duplicated before it got to Postfix.
If you internalise the above logic, you won't need to guess, you
can just find where the envelope splits, prior to BCC rewrites.
It is also best to avoid adding the BCC address more than once, so
ideally enable address rewriting either only before or only after the
content filter. Look for "receive_override_options" in FILTER_README.
--
Viktor.
