On Fri, Mar 5, 2021 at 4:26 AM Viktor Dukhovni <postfix-us...@dukhovni.org> wrote: > > 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.
What I'm going to to do is start with a minimal postfix install and rebuild from scratch and do some testing. Best way to learn this, I think. Thanks for your help.
