And it is easy enough to do "F2F" in a manner that does not break the
authentication-based service.
How?
The system sending the mail signs it. That's one of the great
advantages of DKIM, the signature doesn't have to match other header
addresses such as To: or From:.
A user whose domain publishes adsp=discard couldn't successfully use
such a service, but that's a limitation of ADSP, not of F2F mail or of
DKIM.
R's,
John
_______________________________________________
NOTE WELL: This list operates according to
http://mipassoc.org/dkim/ietf-list-rules.html