Re: [dmarc-ietf] ARC questions
Dave Crocker <dcrocker@gmail.com> Mon, 23 November 2020 22:30 UTC
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To: John Levine <johnl@taugh.com>, dmarc@ietf.org
References: <dcc265f9-a143-5093-eba0-94ee059c7cc7@mtcc.com> <CAMSGcLCzN5q_p_TtUqv5CvwC0ZTkAY9eFaT_za-1WJXgRUmF4A@mail.gmail.com> <CAHej_8nN+827KB+tTuyoeZXoUaKzcYoeizNmwSY-fKTquroPMA@mail.gmail.com> <e3d428f4-1a29-4c6f-4a31-96a24a347e54@gmail.com> <rph9gd$2mp3$1@gal.iecc.com>
From: Dave Crocker <dcrocker@gmail.com>
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Date: Mon, 23 Nov 2020 14:30:30 -0800
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Subject: Re: [dmarc-ietf] ARC questions
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On 11/23/2020 1:27 PM, John Levine wrote: > In article <e3d428f4-1a29-4c6f-4a31-96a24a347e54@gmail.com>, > Dave Crocker <dcrocker@gmail.com> wrote: >>> I believe, though, that the intent of ARC is that it be scalable in >>> ways that manual enumeration of known legit mailing lists and >>> forwarders is not. >> "if you know which hosts are legit" buries an assumption that is >> problematic, namely that you know who handled the message. The fact >> that a message purports to be handled by a mailing list you trust does >> not mean it actually was. > Pretty close, but not quite. > > You know that a message came from a mailing list because you have your > list of IPs or DKIM signatures of lists you trust. Except that was not stated or, really, even implied in the text of the message I was replying to. Rather, something like that seemed to be taken as an assumption, but without any clear foundation. For these kinds of discussions, which are mostly about understanding these capabilities clearly, accurately, and precisely, the core requirement is to separate the essential bits of information and the basis for knowing each bit. > ARC deals with the problem that most list software forwards everything > with a subscriber's address on the From: line and does a lousy job of > spam filtering. Forgive me but I believe misbehavior by mailing lists has never been meaningfully documented for this work. Quite the contrary. List mail has been collateral damage, not because lists have misbehaved but because they got caught by a spontaneous change in the email service by some providers. d/ -- Dave Crocker dcrocker@gmail.com 408.329.0791 Volunteer, Silicon Valley Chapter American Red Cross dave.crocker2@redcross.org
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- Re: [dmarc-ietf] ARC questions John Levine
- Re: [dmarc-ietf] ARC questions Kurt Andersen (b)
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Douglas E. Foster
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Douglas E. Foster
- Re: [dmarc-ietf] ARC questions Joseph Brennan
- Re: [dmarc-ietf] ARC questions Todd Herr
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions Doug Foster
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions Todd Herr
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John Levine
- Re: [dmarc-ietf] ARC questions John Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Dave Crocker
- Re: [dmarc-ietf] ARC questions John Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Seth Blank
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Douglas Foster
- Re: [dmarc-ietf] ARC questions Murray S. Kucherawy
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Murray S. Kucherawy
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Murray S. Kucherawy
- Re: [dmarc-ietf] ARC questions Alessandro Vesely
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John Levine
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions John R Levine
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Michael Thomas
- Re: [dmarc-ietf] ARC questions Benny Pedersen
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Brandon Long
- Re: [dmarc-ietf] ARC questions Michael Thomas