Subject: RE: (ngtrans) Re: including ipv4 address space into ipv6 address space

From: "Michel Py" <[email-masked]>
Date: Tue, 13 Nov 2001 10:31:06 -0800

> From: Christian Huitema [mailto:[email-masked]] 
>> it should indeed be possible to request an A record over IPv6,
>> or an AAAA record over IPv4.

I have done the later many times, mostly because I am too lazy ^H^H^H
busy to upgrade the laptop that I am using in the field to get an
IPv6-compatible nslookup. It works on most servers these days.

If it is debatable to allow or not AAAA (or any v6 RR) queries over v4,
it would be really helpful to leave it fully open at least for nslookup.

Michel.

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From: Keith Moore <[email-masked]>
Date: Tue, 13 Nov 2001 13:51:11 -0500

> it would be really helpful to leave it fully open at least for nslookup.

it's not even debatable, unless you expect DNS caches to keep separate
cached information obtained from v4 and cached information obtained via
v6.  nor is it useful to do so.  

even v4-only apps can benefit by being able to determine that there are 
v6 addresses for a destination - for instance, a v4-only email message 
transfer agent (MTA) can recognize that a particular recipient address
is accessable only via IPv6, and relay that message to its destination
via a willing dual-stack MTA.  if it does not know of a willing MTA,
it can at least emit a useful error message.

Keith

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From: "Jeroen Massar" <[email-masked]>
Date: Tue, 13 Nov 2001 21:57:37 +0100

Keith Moore <[email-masked]> wrote:

> cached information obtained from v4 and cached information 
> obtained via v6.  nor is it useful to do so.  

Is there a reason to NOT allow one to query AAAA or A over IPv6 or IPv4
???
There would be no advantage afaik...

If one would argue to block AAAA queries over IPv4 one should also block
CHAOS class requests and only allow them over the CHAOS protocol...
Also if a company/entity wants to block this.... they should do that on
their side with bind's view or similar approaches.

The current setup, IPv4 and IPv6 can query anything they want, only has
advantages... for example one can determine that the host it exists but
only on IPv6...
It also allows for 'fallback' scenarios used today for HTTP/SSH/etc...
If it gets 'blocked' one would need to do a IPv4 query (for the A) and
an IPv6 query (for the AAAA)..... that's lunacrist ;)

Greets,
 Jeroen