[ietf-dkim] Re: New issue: What is the purpose of SSP? {3.5}

[Frank Ellermann]

Michael Thomas wrote:

> We have to have MUST requirements for the SSP protocol, but
> there isn't a MUST USE SSP requirement for any given DKIM
> verifier.

+1

In other words SSP-MUST means "if you do SSP you MUST get it
right".  An example from the also voluntary SPF:  If the
receiver aborts SPF-evaluation for his own private reasons
(no TempError, let alone PermError) it's fine, but then this
receiver shouldn't add a dubious Received-SPF: NONE (or even
NEUTRAL) trace header field, because that would be a lie.

Frank