> On 2026-09-11 at 15:10:45 UTC-0400 (Fri, 11 Sep 2026 21:10:45 +0200) > Benoît Panizzon via mailop <[email protected]> > is rumored to have said: [snip] > > Coding around this issue also is not tivial - adding a customer header > > with a base64 encoded recipient list would be feasible - but it is one > > email in the postfix queue - can I tell postfix to clone that email and > > send it to each recipient separately? If so, I have the same issue, I > > added the header probably with a MILTER when the RCPT TO phase is done > > so at that moment I only have ONE message with a recipient list. > > It is in fact trivial to fix this with Postfix: > > default_destination_recipient_limit = 1 > > OR: > > smtp_destination_recipient_limit = 1 > > This forces Postfix to deliver a message that has been > submitted with multiple recipients as multiple > one-recipient messages. It is invisible to the sending user. [snip]
We've been using this setting for more than a decade. Postfix handles it very well, and it's almost completely transparent to our users. What changes is that delivery errors are focused on one recipient instead of multiple, which actually simplifies non-delivery notices for end-users (many users find it confusing to read an error report that lists multiple recipients, because intuitively their immediate question is "which one is having the problem?"). The queue has more entries in it as a result, which is fine since Postfix has a well designed queue, and it's also convenient for postmasters who need to manually act on messages for a specific recipient without impacting any of the other recipients addressed in the original message(s) -- in short, easier queue management. -- Postmaster - [email protected] Randolf Richardson, CNA - [email protected] Inter-Corporate Computer & Network Services, Inc. Vancouver, Beautiful British Columbia, Canada https://www.inter-corporate.com/ _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
