Re: [DNSOP] Why would a v4 client send AAAA query?

Naveen Kottapalli <naveen.sarma@gmail.com> Thu, 29 August 2019 01:21 UTC

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From: Naveen Kottapalli <naveen.sarma@gmail.com>
Date: Thu, 29 Aug 2019 06:51:12 +0530
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To: Joe Abley <jabley@hopcount.ca>
Cc: dnsop@ietf.org
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Subject: Re: [DNSOP] Why would a v4 client send AAAA query?
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Hello Joe,

Thanks for answering my question appropriately. I got the answer am
looking for.

Also, thanks for *not suggesting unsolicitedly. * It shows how matured you
are.

Thanks,
Naveen


On Wed, 28 Aug 2019, 06:04 Joe Abley, <jabley@hopcount.ca> wrote:

> Hi Naveen,
>
> On 27 Aug 2019, at 20:23, Naveen Kottapalli <naveen.sarma@gmail.com>
> wrote:
>
> > Can one of you tell why would a v4 client send AAAA query or a by client
> send a A query when the resolved address cannot be used?
>
> Sometimes you can't tell if you can use an address until you find out what
> it was. You might have some but not all routes for a particular address
> family, for example.
>
> Sometimes you request DNS resource records on behalf of other devices that
> have different connectivity from your own.
>
> Sometimes devices make queries for reasons other than sending datagrams
> across a network.
>
> Sometimes the connectivity a device can have can change, depending on what
> network it joins or changing conditions on a network it has already joined.
>
> A device might have both v4 and v6 connectivity and still use v4 to send a
> query with QTYPE=AAAA or v6 to send a query with QTYPE=A. Perhaps the
> device knows that the v4 address its using tends to respond quicker than
> the v6 address it has tried in the past, or perhaps it's random selection,
> or local policy, or something else.
>
> Bill's answer was pithier, though.
>
>
> Joe
>