On Apr 17, 2014, at 4:11 PM, Martin Rex <mrex@xxxxxxx> wrote: > Yoav Nir wrote: >> >> On Apr 17, 2014, at 9:35 AM, Dave Cridland <dave@xxxxxxxxxxxx> wrote: >>> >>> Right now, my MUA treats this as a message >>> "From John R Levine <johnl@xxxxxxxxx>". This means that any policy >>> on the message origination comes from looking solely at the taugh.com >>> domain. We'll pretend it has a DMARC policy. Herein lies the >>> Yahoo/DMARC issue, because unless your policy essentially stipulates >>> that the IETF is allowed to spoof you, we're stuck. >> >> Then perhaps this is what needs to change. John R Levine did not send >> you a message. He sent a message to the list. It is the list software >> that sent you a message. So perhaps the From field should have been >> ?From: IETF Mailing list on behalf of John R Levine <ietf@xxxxxxxx>?. > > But that is EXACTLY what the IETF mailing list exploder *IS* doing > exactly as it has been specified for ages: > > https://tools.ietf.org/html/rfc822#section-4.4.2 > https://tools.ietf.org/html/rfc822#appendix-A.2 > > https://tools.ietf.org/html/rfc5322#section-3.6.2 > > The "From:" field specifies the author(s) of the message, > that is, the mailbox(es) of the person(s) or system(s) responsible > for the writing of the message. The "Sender:" field specifies the > mailbox of the agent responsible for the actual transmission of the > message. > > From: Yoav Nir <ynir.ietf@xxxxxxxxx> > Subject: Re: (DMARC) Why mailing lists are only sort of special > Errors-To: ietf-bounces@xxxxxxxx > Sender: ietf <ietf-bounces@xxxxxxxx> > Date: Thu, 17 Apr 2014 13:50:30 +0300 > Message-ID: <B3467912-BDCA-4AE8-9939-60013DA99267@xxxxxxxxx> > To: Dave Cridland <dave@xxxxxxxxxxxx> > CC: "ietf@xxxxxxxx" <ietf@xxxxxxxx> > > > Something as old as Outlook 2003 will properly display a message > that is received with a "Sender:" as "<Sender> on behalf of <From>” A client as new as Mail.app on Mac OS X 10.9 does not. Obviously the Sender: field is not where the DMARC implementations use for checking policy. Yoav