[dmarc-ietf] Re: I-D Action: draft-ietf-dmarc-arc-to-historic-00.txt

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

On Sun, May 10, 2026 at 3:14 AM Tero Kivinen <[e-mail]> wrote:

> >     But when you set up the forwarding that means you do trust google.
> >
> > I, personally, might.  But there's no reason for the two operators
> > to trust each other just because I said so.
>
> The operators does not need to trust each other. There is no system
> wide trust. I as an user of the system X, will trust system Y, as I
> myself set it up to forward emails to my system X address. If I do not
> trust system Y, why would I set up the forwarding in the first place?
>
> The system X only trust system Y when it is processing my emails, it
> does not affect anybody else on the system X.


Unless the model has changed since I last worked hands-on in this space,
the system/operator validates DKIM and ARC and acts on the results.  In
such a world, it's possible for Y to reject mail from X if X develops a
sufficiently poor reputation.  I understand that's a desirable outcome.

But you're saying user@X and user@Y can assert a trust relationship that
the operator is expected to honor.  This might preclude the idea that Y can
reject mail from X without inspecting the user-specific identities involved.

This seems contradictory to me.  DKIM and ARC act at the domain level.
Involving user-specific logic seems like complexity that belongs at a layer
above where those two operate.

-MSK