[mail-vet-discuss] Auth-Results installed base

[SM]

Hi Doug,
At 18:39 03-11-2008, Douglas Otis wrote:
>The motivation for this header is in support of a questionable Sender-
>ID or SPF path registration scheme.  Sender-ID is being sold as a
>replacement for source authentication.

The Authentication-Results header was introduced in 2004 as there 
wasn't a standardized method to convey the results of DomainKeys verification.

>Not having this border header as a substitute for DKIM validation
>ensures ISPs will provide access to unmodified messages.  To ensure
>security, verifying the DKIM signature should be done by the MUA
>making the annotation, rather than depending upon an injected third-
>party header.

If you go back through the DomainKeys and DKIM archives, you might 
find that it was deemed unpractical to expect all MUAs to do DKIM 
verification.  That doesn't preclude MUAs from doing DKIM 
verification if they support it.  It can be problematic in cases 
where the DKIM signature is time sensitive.

Regards,
-sm