Re: [BEHAVE] Learning IPv6 translator's prefix - draft-wing-behave-learn-prefix-03

> -----Original Message-----
> From: behave-bounces@ietf.org 
> [mailto:behave-bounces@ietf.org] On Behalf Of Anthony Roberts
> Sent: Wednesday, July 22, 2009 7:35 AM
> To: Brian E Carpenter
> Cc: Behave WG; Dan Wing; Chen Gang
> Subject: Re: [BEHAVE] Learning IPv6 translator's prefix - 
> draft-wing-behave-learn-prefix-03
> 
> Hi Brian,
> 
> With respect to BIS/BIA, adding a way to discover the prefix will not
> prevent application developers from implementing their own 
> workarounds when
> needed to run on operating systems that don't yet support this. In the
> absence of a better alternative, developers will resort to 
> discovering the
> prefix themselves via DNS and synthesizing addresses within their
> application.

Sure.

> At a minimum it seems prudent to specify the circumstances when
> applications may attempt discovery/synthesis.

That implies the application can determine if the underlying IP stack
does, or doesn't, have BIS/BIA and translation built in.  Or can 
determine if that underlying support is (somehow) inadequate (e.g.,
buggy or has known incompatibilities with whatever the application
needs).

> It would also be possible to
> extend the DNS64 to provide AAAA records with names based on 
> IPv4 literals
> in a well known .arpa DNS zone; that would at least contain address
> synthesis to one of the places it already has to exist.

Not sure what you mean - can you provide an example or explain it
differently?  I'm stuck on "names based on IPv4 literals".

-d

> Regards,
> 
> -Anthony
> 
> On Tue, 21 Jul 2009 12:13:57 +1200, Brian E Carpenter
> <brian.e.carpenter@gmail.com> wrote:
> > On 2009-07-20 22:58, Chen Gang wrote:
> >> I guess that my point hasn't been clarified enough,
> >> 
> >> What I am saying is that NAT64 draft is based on the Ipv6 
> only host,
> >> But the question here is how could "http://1.2.3.4" be processed by
> >> network
> >> stack,
> >> will IPv4 socket api be called or will IPv6 socket api be called.
> > 
> > Firstly, should we really be spending effort on this problem? What's
> > wrong with an error response to the user? Address literals 
> are supposed
> > to be for diagnostic use only. "No IPv4 available" would be an
> appropriate
> > diagnostic message.
> > 
> > Secondly, as others have observed, RFC3338 documented a solution 7
> > years ago, to which we need to add a way to determine the correct
> > v6 prefix to use. The same goes for RFC2767.
> > 
> >     Brian
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