Re: [dmarc-ietf] DMARC bis: ticket 49: remove normative requirement on policy tag placement

[Scott Kitterman <[e-mail]>]

On Friday, May 15, 2020 2:26:30 PM EDT Seth Blank wrote:
> https://trac.ietf.org/trac/dmarc/ticket/49
> 
> The penultimate paragraph of https://tools.ietf.org/html/rfc7489#section-6.3
> states:
> 
> the "v" and "p" tags MUST be present and MUST
>    appear in that order.
> 
> While the v= tag pretty universally appears first, the p= tag does not in
> many records, and no implementation appears to care.
> 
> The v= tag must appear first, or the policy discovery mechanism as defined
> in https://tools.ietf.org/html/rfc7489#section-6.6.3 would break.
> 
> But there doesn't appear to be any real reason to keep the normative
> requirement that the p= tag MUST be second in the record after the v= tag,
> nor does this requirement seem to have any impact on interoperability or
> general record parsing in theory or in practice.
> 
> Should we remove this normative requirement?

Section 6.6.3, step 6, sub-step 1 already says:

>        1.  if a "rua" tag is present and contains at least one
>            syntactically valid reporting URI, the Mail Receiver SHOULD
>            act as if a record containing a valid "v" tag and "p=none"
>            was retrieved, and continue processing;

I don't see a problem with changing the MUST for p= to SHOULD and adding a 
MUST p= or rua=.  That's consistent with what we already tell receivers they 
SHOULD do.

Scott K