John C Klensin wrote:
> --On Wednesday, April 02, 2008 11:25 AM -0700 Lisa Dusseault wrote:
>> WWTHD (What Would Ted Hardie Do): be blunt. "After much
>> discussion on the topic, this specification does not extend
>> the A rule to AAAA records, but neither does it preclude a
>> parallel treatment."
That leaves an ambiguity about behavior from which neither SMTP clients
nor domain administrators can figure out what to do. To me, that
ambiguity is the one case that is a showstopper. It also, IMO, creates a
"known technical defect" and that would exclude even publishing
something as Proposed, much less Draft.
I see no way to avoid making a choice.
I think I and several others have said this before, but I can live with
anything that (i) does not create an ambiguity and (ii) does not
deprecate the existing (back to 974) behavior.
I'm sorry to say that I see a way to deal with v6, without dealing with it.
Unfortunately, I see Lisa's language as too specific as well as too varied.
"does not extend...to...but neither does it precludes" is, I believe,
semantically equivalent to saying "is out of scope". That's language that is
more typical in IETF specifications.
So I think the choice is between
1. The current draft language, which treats "direct" addresses as a list and
names two entries, A and AAAA, explicilty, versus
2. Language which cites A but declares all other details out of scope, using
"In the absence of indirect addressing, via a DNS MX record, this
specification provides for use of direct addressing via IPv4 DNS A records. Use
of other direct addresses is out of scope."
FWIW, I vote for 1. v6 is too real to ignore.
I also suspect a diligent IESG would enforce including it as a requirement.