Public bug reported: Keeping DKIM signature intact allows passing DMARC without from munging (I have references all about this if needed). However, mailman modifies the cc header when a subscriber has the nodup setting and someone sends to the list with that subscriber cced. Mailman doesn't email them and removes them from the cc, presumably so for further replies mailman can email them without it being a duplicate and they get all the good mailman headers instead of a plain email from the cc. Anyways, best if Mailman just not modify the cc if we are in the situation where it matters for passing DMARC. The attached patch does that. Note, I'm sending this as an employee of the Free Software Foundation and my copyright is already going to them. ** Affects: mailman Importance: Undecided Status: New ** Patch added: "nodup-dkim.patch" https://bugs.launchpad.net/bugs/1845751/+attachment/5292024/+files/nodup-dki... -- You received this bug notification because you are a member of Mailman Coders, which is subscribed to GNU Mailman. https://bugs.launchpad.net/bugs/1845751 Title: cc modification due to nodup setting breaks DKIM & thus DMARC To manage notifications about this bug go to: https://bugs.launchpad.net/mailman/+bug/1845751/+subscriptions