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?
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.
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.
I think Tony's decision was the right one - FOR 2821bis.
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 and this is why I wish to see a new effort for a modern,
consolidated SMTP Ipv6/4 technical/functional/migration spec. The key
word is consolidated, and I think this spec can augment 2821bis draft
Hector Santos, CTO