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

2008-04-15 20:30:02


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 standard.


Hector Santos, CTO