Subject: Re: How does DNS Queries handle for IPv6 dual stack

Re: How does DNS Queries handle for IPv6 dual stack

From: Zan Lynx <zlynx_at_acm.org>
Date: Tue, 9 Feb 2016 10:27:30 -0700

On 02/09/2016 10:09 AM, kritesh tripathi wrote:
> Hi All,
>
> Is anybody have idea about DNS Query handling by ares lib in IPv6 dual
> stack scenario.
>
> For Example -
>
> If Preferred Network-IPv6 in Dual stack and Primary DNS Server-Ipv6
> ,Secondary DNS Server=Ipv4 then
>
> 1- Is DNS quad A query send first and if it is unsuccessful then
> Standard A query send
> or
> 2- DNS Quad A Query and Standard A query send in parallel which is
> resolved first .. will use accordingly .

I wrote an application that uses c-ares and does A and AAAA queries. I
handled it myself, basically just using whichever query returned first
and caching the other one for possible use later.

I think it is not very difficult to write code for yourself to do this
whichever way that you want it done.

If you are asking about the right way to do it, I don't know if there is
one "correct" way, but there is Happy Eyeballs:
        https://en.wikipedia.org/wiki/Happy_Eyeballs
Received on 2016-02-09