Shepherd writeup

1. Summary

The document shepherd is Scott Kitterman.  The Responsible Area Director is Barry Leiba.

RFC7001 defines the email Authentication-Results header field that presents the results
of an authentication effort in a machine-readable format.  The specification in that
document enumerated a small set of types of  properties that can be reported using this
mechanism.  That constrained set of types has proven to be too narrow.  Accordingly, this
document updates the specification to allow for additional property types ("ptypes")
beyond the original set, and creates a registry where new ones can be listed and their
defining documents referenced.

As an update to RFC 7001, this document is appropriately placed on the standards track.

2. Review and Consensus

This is a simple document and WGLC was quiet (no comments).  There was significant
discussion prior to WGLC with reviews and comments from three different reviewers.
The only significant technical issue that was discussed was the possibility that the version
number of the field might need to be increased.  The unanimous conclusion was that it
does not.

This draft is a precursor to draft-martin-authentication-results-tls.

Once this document relaxes the ptype constraint, other authentication types such as TLS
(mentioned above) are expected.  Multiple participants reported plans to implement these.

3. Intellectual Property

No IPR disclosures have been submitted and the author has indicated he is not aware of
any other IPR issues.

4. Other Points

The IANA considerations appear clear and complete.

This document creates an Email Authentication Property Types registry.  The standard for
update is expert review.