From: Michael Thomas [mailto:mike(_at_)mtcc(_dot_)com]
Hallam-Baker, Phillip wrote:
* A responder (i.e. a server) should post a notice
somewhere that says
'This is what I accept'. The sender can then work out if they can
provide that.
How does the signer know who the verifier(s) will ultimately be?
In a connectionless protocol with forwarding they can't. That is why we
don't use receiver side policy in DKIM and instead require the
signatures to not harm legacy infrastructure.
That side of policy is only really significant for encryption where you
need to know the encryption key in advance. The lack of this capability
is one of the principle problems with S/MIME.