I can hardly believe I actually followed that whole post start to end! Thanks Mark. -------------------------------------------- On Sat, 4/4/15, Mark Sapiro <m...@msapiro.net> wrote:
Subject: Re: [Mailman-Users] DMARC mitigation - was: Templates To: mailman-users@python.org Date: Saturday, April 4, 2015, 1:38 PM On 04/04/2015 09:59 AM, Laura Creighton wrote: > > ps -- anybody know why all mail I see from people on yahoo.com (including JB > here) arrives to me as from yahoo.com.dmarc.invalid. > > It very much seems to be a python.org thing, but, ah, why is python.org > seeing fit to add this stuff? It's DMARC mitigation. Mailman has features for this, but on this list at least they are turned off. See <http://wiki.list.org/DEV/DMARC> for something about DMARC in general and Mailman's mitigation features. The problem is yahoo.com, aol.com and a few other domains publish DMARC policies of 'reject'. For our purposes, this means that a message with a From: address in one of those domains that is not validly DKIM signed by that domain will be rejected by a lot of ISPs. List transformations will break the incoming DKIM sig so the only way to get such a message accepted by many large ISPs is to munge the From: domain in some way. See the archives of this list from last April at <https://mail.python.org/pipermail/mailman-users/2014-April/> for much discussion of this. Mailman's From: address munging will replace, e.g. From: Mark <mark_sap...@yahoo.com> with, e.g. From: Mark via Mailman-Users <mailman-users@python.org> and add the original From: to Reply-To:, but that doesn't happen with python.org mailing lists because the incoming MTA at mail.python.org deals with this differently by just appending .dmarc.invalid to From: addresses @yahoo.com, @aol.com and a couple of other domains. Some people think this approach is less disruptive than Mailman's way - i.e. users when replying are astute enough to just remove the .dmarc.invalid, or if not, maybe they'll figure it out after seeing the bounce DSN. -- Mark Sapiro <m...@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org https://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: https://mail.python.org/mailman/options/mailman-users/jebva%40yahoo.com ------------------------------------------------------ Mailman-Users mailing list Mailman-Users@python.org https://mail.python.org/mailman/listinfo/mailman-users Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: http://www.mail-archive.com/mailman-users%40python.org/ Unsubscribe: https://mail.python.org/mailman/options/mailman-users/archive%40jab.org