Re: [BEHAVE] Happy Eyeballs and DNS64 not sending synthetic AAAA RRs

> -----Original Message-----
> From: behave-bounces@ietf.org [mailto:behave-bounces@ietf.org] On
> Behalf Of Andrew Sullivan
> Sent: Thursday, August 04, 2011 12:07 PM
> To: behave@ietf.org
> Subject: Re: [BEHAVE] Happy Eyeballs and DNS64 not sending synthetic
> AAAA RRs
> 
> On Thu, Aug 04, 2011 at 02:37:47PM -0400, Marc Blanchet wrote:
> >
> > I'm not sure I get your point. If we are in a DNS64 scenario, the
> network between host and the NAT64, as well as the host itself,  is
> IPv6-only. Therefore, there is no such "fall back using IPv4".
> >
> 
> Right.  Every now and then someone talks about what happens when you
> use DNS64 in a dual stack environment.  The answer is, "Doctor, it
> hurts when I do this."
> 
> Don't do it.
> 
> I get why people want to make DNS64/NAT64 more robust than it may be
> as defined.  But this is an attractive nuisance: it's never really
> going to work all the way anyway.  (The twisty problems of detecting
> the DNS64 are already illustrating this.)

A nuance to this problem is that some networks will have a mix
of hosts:

  (a) IPv4-only, which use a 'normal' DNS server
  (b) dual stack hosts, which use a 'normal' DNS server
  (c) IPv6-only hosts, which use a DNS64 server so they
      can use a NAT64 to visit IPv4-only servers.

http://tools.ietf.org/html/draft-wing-behave-dns64-config-03 discusses
the pros/cons of a bunch of mechanisms to provide the correct DNS
server to all three of those host types.

I don't know if there is interest in this problem.  (But I find it
an interesting problem.)

-d

> A
> 
> --
> Andrew Sullivan
> ajs@anvilwalrusden.com
> 
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