Am Fri, 11 Sep 2026 10:44:45 -0500 schrieb Al Iverson <[email protected]>:
> ESPs handle this by encoding a copy of the recipient's email address > into an opaque identifier in a hidden header or the message-ID header, > or an unsub link. Which means a unique message for each recipient. It > can be painful for some use cases, but if you can figure it out, it > should address the problem. Unfortunately not this kind of situation but imagine this one: A Granny inviting all her relatives and friends to her 80 birthday, about 20 recipients in that email, 8 of which are at hotmail or outlook. One is not interested and mistakes 'junk' and 'trash' (oh yes, this is the main cause of S3150 I fear). We get a complaint - we block the email account of Granny, our customer and until short time ago, we sent her a note to please contact XY @ hotmail to check why she/he reported your email as spam - most likely the recipient confused junk and trash - please tell him/her not to put your email in junk, this causes a complaint and damages our ISP mailserver reputation. Well, now we can not tell her anymore which of the 8 microsoft recipients reported her email. 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. I probably would need to switch to a complete different MTA if there is one that does that out of the box and still uses the MILTER interface which we need for a lot of other stuff like SRS, Forwarding, Spamfiltering, etc... -Benoît- _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
