Google no longer returning AAAA records?

Brian E Carpenter brian.e.carpenter at
Fri Apr 17 05:28:29 CEST 2015

On 17/04/2015 15:17, Erik Kline wrote:
> On Thu, Apr 16, 2015 at 7:41 PM, Phil Mayers <p.mayers at> wrote:
>> On 16/04/15 01:57, Lorenzo Colitti wrote:
>>> For the avoidance of mystery: Google performs measurements of IPv6
>>> connectivity and latency on an ongoing basis. The Google DNS servers do
>>> not return AAAA records to DNS resolvers if our measurements indicate
>>> that for users of those resolvers, HTTP/HTTPS access to dual-stack
>>> Google services is substantially worse than to equivalent IPv4-only
>>> services. "Worse" covers both reliability (e.g., failure to load a URL)
>>> and latency (e.g., IPv6 is 100ms worse than IPv4 because it goes over an
>>> ocean). The resolvers must also have a minimum query volume, which is
>>> fairly low.
>> Lorenzo,
>> Thanks for the response.
>> Do you know if Google have given any thought as to how long they might find
>> it necessary to take these measures? Years, indefinitely?
>> Just curious.
> It seems to keep on finding things, so...

But the incentive is wrong. Forcing users to drop back to IPv4 offers
no incentive to fix the IPv6 problem. The correct incentive would be to
tell an operator that they will be blacklisted unless they fix {X and Y}.


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