As someone pointed out, you can interchange steps 1 and 2 in the
specification, putting the existence check first. And then, of
course, you can decide that the existence check is done outside
If the existence check is removed, I would advocate putting in
language that says an existence check SHOULD be
performed before doing ADSP.
That seems reasonable. My objection (and I think also Dave's) is
that it's a bad idea, but that it's not part of DKIM or ADSP.
It's unfortunate that DNS won't let us specify ADSP policies that
cover only non-existent originator domain names, but wishing for such
an ability does not mean that we suddenly can.
The NXDOMAIN result for the originator domain cannot(*) correspond
with an ADSP policy (one of "unknown" / "all" / "discardable"), and
therefore it cannot be part of ADSP.
Would it be an acceptable compromise to add the above (or similar) to
(*) Otherwise we could declare 99.9999% ADSP deployment today.
Hmm, maybe we should do that instead....
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