SSP is about providing the receiver with a means to check whether a
required message characteristic is missing.
Um, required by whom or what?
In the case of SSP as currently written the answer is: the domain from
whom the message itself claims to originate.
Note though that the question of "required by whom or what" is separate
from the assertion that SSP needn't check anywhere for any requirement
whatsoever. In fact, we must first agree that SSP is about checking for
such a requirement before we can discuss from whom or what. It is this
fundamental characteristic of SSP that issue 1521 calls into question.
Arvel
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