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Re: I-D Action:draft-klensin-rfc2821bis-10.txt

2008-04-16 11:12:26

Hector Santos <hsantos(_at_)santronics(_dot_)com> wrote:
John Leslie wrote:

My hope has been that an IPv6-only host speaking SMTP to the rest of
the world would:

- look for an MX RR pointing to an AAAA RR
  - if it finds one, use that AAAA RR
  - if not, look for an MX (explicit or implied) pointing to an A RR
    - if it finds one, pass the email to a friendly relay speaking IPv4
    _ if not, give the usual error

- advertise an MX RR pointing to an A RR
  (in addition to any pointing to AAAA RRs)

I'm confused. To me, when you say "IPv6-only", that implies it doesn't 
support IPv4 in any direct way.  Isn't that correct?


   The distinction I intend is that the host has no IPv4 connectivity.

This strikes me as a more reasonable long-term algorithm than
requiring all mail from an IPv6 user to go through a SMTP server with
both IPv4 and IPv6 connectivity.

It may be that the consensus here prefers Hector's solution: if so,
I suppose I should shut up. But please think long-term: we want something
that can work today and continue working for 20 years, by which time
IPv4 should be as rare as IPv6 is today.

I don't think I have been any different from what you desire.  We might 
said it in different ways but I think we all want the same thing.

   It's hard to tell...

   Undeniably, we could stipulate that an IPv6-only domain MUST pass
all outgoing email to an IPv4-capable host. That is not what I want.
Your posting led me to believe it was what you wanted.

My only real point about the IPv6 related considerations was how it 
would be stated in a kludged up, "spaghetti" 2821bis in such a way
that will promote interoperability issues with the dominant IPv4
market for now and the foreseeable future.

   It's hard, again, to tell what you mean by this. I certainly do
not desire a "spaghetti" 2821bis. To me, a 2821bis that's hard to
understand and implement _can't_ promote interoperability.

I think Tony's decision was the right one - FOR 2821bis.

   I'm forced to face the unfortunate fact that anything I write will
be interpreted as an attack on Tony by some people (fortunately _not_
by Tony himself).

   The folks who are best at protocol design _don't_ automatically
forget an idea when the majority rejects it. (And neither do I.)
They do, however, shift their concentration to a different area.
I believe I have done so. Others may disagree...

I could elaborate more about IPv6 concerns but overall I think we
still do not know what all the real issues with IPv6 implementations
in a IPv4 world [may be]

   We don't need to know "all" the issues in order to design "an"
algorithm for interaction. I have suggested one. (Its mirror image
should work in the opposite direction.)

and this is why I wish to see a new effort for a modern, consolidated
SMTP Ipv6/4 technical/functional/migration spec.

   Are you volunteering?

The key word is consolidated, and I think this spec can augment
2821bis draft standard.

   "Augment" is certainly OK... "Override" probably isn't.

John Leslie <john(_at_)jlc(_dot_)net>