Re: [dmarc-ietf] Description of 'n' value for the 'psd' tag AND/OR Clarify the Tree Walk

[Todd Herr <[e-mail]>]

On Wed, Apr 17, 2024 at 1:18 AM Neil Anuskiewicz <neil=
[e-mail]> wrote:

>
>
> On Apr 16, 2024, at 2:18 PM, Todd Herr <todd.herr=
> [e-mail]> wrote:
>
> 
> Colleagues,
>
> DMARCbis currently describes the value of 'n' for the 'psd' tag in a
> policy record as follows:
>
> The DMARC policy record is published for a PSD, but it is not the
> Organizational Domain for itself and its subdomain. There is no need to put
> psd=n in a DMARC record, except in the very unusual case of a parent PSD
> publishing a DMARC record without the requisite psd=y tag.
> I don't think this is entirely accurate, especially the second sentence
> ("no need ... except in the very unusual case"), and here's why. Either
> that, or the description of the Tree Walk needs to be changed.
>
> The Tree Walk is intended for both DMARC Policy discovery and
> Organizational Domain discovery, and section 4.7 (DMARC Policy Discovery)
> says the policy to be applied will be the DMARC record found at one of
> these three locations:
>
>    - The RFC5322.From domain
>    - The Organizational Domain of the RFC5322.From domain
>    - The Public Suffix Domain of the RFC5322.From domain
>
> Meanwhile, section 4.8, Organizational Domain Discovery, gives the
> following three options for where the Organizational Domain is:
>
>    1. DMARC record with psd=n
>    2. The domain one level below the domain with a DMARC record with the
>    tag psd=y
>    3. The record for the domain with the fewest number of labels.
>
> The Tree Walk, as described in section 4.6, defines two explicit places to
> stop, both of which rely on discovery of a DMARC policy record with a psd
> tag defined.
>
>
> One of your concerns is that without a PSD tag, but I think the default is
> PSD=n. Does,that address that concern or did I misunderstand the concern?
>
>
The default for the psd tag is 'u', not 'n'.

See
https://www.ietf.org/archive/id/draft-ietf-dmarc-dmarcbis-30.html#name-general-record-format

-- 

Todd Herr | Technical Director, Standards & Ecosystem
Email: [e-mail]
Phone: [phone]


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