Hi Platonides, Please see my comments inline below :) This would result in multiple addresses in the Reply-to: header like this: Reply-to: sender(a)example.com, list(a)lists.wikimedia.org Pressing reply should then open a message with both addresses in the To: field. If desired dmarc_moderation_notice can bet set on a per-list basis to explain why the message was rejected. This will not change the from addresses displayed in archives and unless you have a static contact book entry for the list address the sender name should appear in the thread as “First Last via list". I’m not sure about gmane, but in this case it might be more straightforward to reject DMARC senders and avoid inconsistencies between archives. Best, —Keith

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Danny, On 26/07/2017 08:59, Danny B. wrote: There is a setting for this too :) Every individual member of the list has a "nodupes" setting, which tells Mailman to detect that their email address has already received a direct copy, and tells Mailman to not send the mailing list copy too. On the one mailing list I have access to the membership list for, everyone (41 members) has this setting set. I think it's a default for our list, but I don't know if it's the default globally too. Simon --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 As a mail server administrator who has been forced to deploy DMARC to combat spammers spoofing my domains in their emails, I have to say that I rather resent the characterization of my choice to use DMARC to enforce SPF and DKIM checks as me configuring my domain to not allow its users to send emails to mailing lists. Without DMARC, spammers would be able to send emails with fake From: headers to make it appear as if the spam is coming from me - and, actually, they do try according to the DMARC data I receive back from Google - which negatively impacts my domain's ability to send legitimate mail. With all due respect, saying that "DMARC is not for providers of people using mailing lists" strikes me as rather ignorant. It's also worth noting that DMARC is itself only a way for email providers to specify to recipients how strictly the already existing SPF and DKIM checks should be applied, nothing more. I, for one, think that even if it is suboptimal, changing the From: header to the mailing list's address is the best solution and appreciate the plan to do this. It will allow mail providers who have chosen to secure their email delivery using DMARC to use these mailing lists, and perhaps even allows the WMF to, in the future, adopt DMARC - we have already seen on OTRS examples of spammers using fake wikimedia.org From: headers in spam emails, and wide DMARC deployment would have a significant impact in reducing spam of this nature across the entire Internet. I think it's also worth noting that the very large Outages mailing list <https://puck.nether.net/mailman/listinfo/outages>, which is popular amongst network admins including myself, has changed the From: headers of its emails to be via the mailing list as proposed here for as long as I have been a member of the list. In summary, I strongly feel that this is a relatively easy change that is a major step in the right direction towards supporting an important technology that will help combat spam across the entire Internet, and I wholeheartedly support it. - -- Sincerely, Andrew "FastLizard4" Adams <https://en.wikipedia.org/wiki/User:FastLizard4> <https://fastlizard4.org> &lt;FastLizard4(a)gmail.com&gt; GPG Key ID: 0x221A627DD76E2616 On 7/25/2017 16:01, Platonides wrote: