Re: [dmarc-ietf] Proposed text for p=reject and indirect mail flows

I'm happy with that suggestion.

Barry

On Thu, Mar 30, 2023 at 6:00 AM Scott Kitterman <sklist@kitterman.com> wrote:
>
> Would you feel any better if the MUST NOT was followed by 'to preserve interoperability '?  That's implicitly there and I believe technically correct.  If you value other properties of the system higher than interoperability, then the advice may not apply, which is fine.
>
> Scott K
>
> On March 29, 2023 3:32:10 PM UTC, "Brotman, Alex" <Alex_Brotman=40comcast.com@dmarc.ietf.org> wrote:
> >I’m just not sure how we determine what is high-value.
> >
> >comcast.com: p=reject
> >comcast.net: p=none
> >xfinity.com: p=quarantine
> >
> >The top one is corporate, middle is consumer, bottom is consumer (but not actually used) & customer comms (sub-domains).  They’re all used in various ways for internal messaging.  Should I tell our corporate admins that they need to no longer publish p=reject?  They’re violating the RFC by doing so?  There are very few consumer-oriented messages that originate from comcast.com.  Are we doing it right?  It makes things a little harder when one of our employees wants to use a mailing list.  But that still feels like the right thing to do.
> >
> >If it’s not obvious, I’m having a hard time with “MUST NOT”, and dictating to domain owners what is in their best interests, regardless of our perceived value of their domain.
> >
> >--
> >Alex Brotman
> >Sr. Engineer, Anti-Abuse & Messaging Policy
> >Comcast
> >
> >From: dmarc <dmarc-bounces@ietf.org> On Behalf Of Barry Leiba
> >Sent: Wednesday, March 29, 2023 10:15 AM
> >To: Todd Herr <todd.herr=40valimail.com@dmarc.ietf.org>
> >Cc: dmarc@ietf.org
> >Subject: Re: [dmarc-ietf] Proposed text for p=reject and indirect mail flows
> >
> >I'm very much against text such as this, as I think it encourages deployments that are contrary to interoperability and to the intent of p=reject.
> >
> >I contend that p=reject (as with the similar construct in the older ADSP) was intended for high-value domains and transactional mail, and that it was never intended for use in domains where general users send general email.
> >
> >I stand by the MUST NOT that I proposed.
> >
> >Barry
> >
> >
> >On Wed, Mar 29, 2023 at 10:33 PM Todd Herr <todd.herr=40valimail.com@dmarc.ietf.org<mailto:40valimail.com@dmarc.ietf.org>> wrote:
> >On Tue, Mar 28, 2023 at 9:06 PM Pete Resnick <resnick@episteme.net<mailto:resnick@episteme.net>> wrote:
> >
> >If you agree that interoperability is increased, then I'd suggest that you actually do agree that the proposed text is appropriate.
> >
> >
> >I don't know that I agree that interoperability is increased...
> >
> >I'm having trouble squaring proposed language that says "Domain owners MUST NOT publish p=reject because it breaks interoperability" with the following language from section 5.8:
> >
> >
> >Mail Receivers **MAY** choose to accept email that fails the DMARC
> >
> >mechanism check even if the published Domain Owner Assessment Policy
> >
> >is "reject". In particular, because of the considerations discussed
> >
> >in [@!RFC7960], it is important that Mail Receivers **SHOULD NOT** reject
> >
> >messages solely because of a published policy of "reject", but that
> >
> >they apply other knowledge and analysis to avoid situations such as
> >
> >rejection of legitimate messages sent in ways that DMARC cannot
> >describe, harm to the operation of mailing lists, and similar.
> >
> >It seems inconsistent to state with certainty that authorized mail will be rejected due to authentication breakage when there is no requirement that a reject policy be honored (and we have plenty of evidence that Mail Receivers are following the 'SHOULD NOT reject messages' guidance).
> >
> >Language that would be more consistent in guidance to the domain owners might look something like this:
> >
> >After careful analysis of the aggregate report data as described in section 5.5.5
> >(Collect and Analyze Reports), Domain Owners **MAY** choose to change their
> >policy from 'none' to 'quarantine' or 'reject'. If, in the Domain Owner's judgement,
> >unauthorized and deceptive use of its domain name in the RFC5322.From field puts
> >at risk the trust it has built with its recipients, then it is **RECOMMENDED** that
> >the Domain Owner make use of the p and/or sp tags to set policy to 'quarantine' or
> >'reject' for those streams most at risk of loss of trust.
> >
> >If going that route, probably want to consider expanding on 5.5.5, too; I need to think about it some more.
> >
> >--
> >Todd Herr | Technical Director, Standards and Ecosystem
> >e: todd.herr@valimail.com<mailto:todd.herr@valimail.com>
> >m: 703.220.4153
> >
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