Re: [dmarc-ietf] A-R results for DMARC

["Murray S. Kucherawy" <[e-mail]>]

On Mon, Dec 7, 2020 at 7:16 PM John Levine <[e-mail]> wrote:

> I have never understood all of the indirection involved in defining
> stuff for A-R but I'm hoping Murray can help out.
>

What I think you're referring to is a distinction between the way we seem
to want to use A-R now versus how it was originally intended.

The original intent back in RFC 5451 was to relay only those details that
an MUA might care about, such as the DKIM result (so you can display
something representing a "pass" or "fail" on a message) and maybe the
domain name found in a passing signature (an early shot at caring about
alignment when rendering a message).  The community seems to have shifted
toward that being too strict and instead wanting to use it as a transport
mechanism for any evaluation detail about the message that might be
interesting to the MUA or any other downstream agent once it reaches its
final ADMD.  RFC 8601, for instance, registered "header.a" and "header.s",
DKIM properties that are almost certainly of no interest to MUAs.

So that ship has sailed, meaning yes, we could register these too if
they're going to be useful to downstream agents.  Though for that matter,
you could just start using them even without registering them to see if it
would be helpful, because 8601 allows for local conventions (the
tried-and-true "ignore what you don't know" thing that DKIM introduced).

-MSK