Re: [dmarc-ietf] Doing a tree walk rather than PSL lookup

Dave Crocker <> Tue, 24 November 2020 15:36 UTC

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To: Todd Herr <>, IETF DMARC WG <>
References: <20201123213846.EB14127C8160@ary.qy> <> <> <> <>
From: Dave Crocker <>
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Date: Tue, 24 Nov 2020 07:36:40 -0800
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Subject: Re: [dmarc-ietf] Doing a tree walk rather than PSL lookup
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Just to be clear, I'm not challenging the need.  Rather I'm just looking 
for text that explains the need.  And I'm not finding it...

On 11/24/2020 7:28 AM, Todd Herr wrote:
> There are two reasons (at least) for needing the Organizational 
> Domain, and they are discussed in RFC 7489:
>  1. DMARC also allows for the explicit or implicit expression of
>     policy for sub-domains at the Organizational Domain level. This
>     matters for those times when _dmarc.RFC5322.From.domain is
>     non-existent and RFC5322.From.domain is a sub-domain of the
>     Organizational Domain.
>  2. The default mode for authenticated identifier alignment, relaxed,
>     requires only that the Organizational Domains for both identifiers
>     are the same, and so the Organizational Domain must be known in
>     order for relaxed alignment to be ascertained.
Except that I do not find either of these points provided in the document.

> What is perhaps missing from RFC 7489 is the reason that the authors 
> chose to make these two items part of the specification.

That would, of course, also be nice to include.


Dave Crocker

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American Red Cross