I went through it. It's a very thorough piece of work.
So far I only have two comments.
Section 3.5, near the bottom of page 23:
Local- part MAY be drawn from a namespace that does not contain the
user's mailbox
I'd suggest changing that to
Local- part MAY be drawn from a namespace unrelated to any mailbox.
The document never says who "the user" is, and I see no advantage to
language that implies that there is one.
Section 7:
Should this section reiterate all of the stuff in 4871, or since the
IANA registry already exists, just say what if anything is different
since 4871? I don't know which is better.
http://www.iana.org/assignments/dkim-parameters/dkim-parameters.xhtml
R's,
John
_______________________________________________
NOTE WELL: This list operates according to
http://mipassoc.org/dkim/ietf-list-rules.html