Yahoo and IPv6

Warren Kumari warren at
Tue May 10 02:15:57 UTC 2011

On May 9, 2011, at 9:14 PM, Owen DeLong wrote:

> On May 9, 2011, at 9:25 AM, Valdis.Kletnieks at wrote:
>> On Mon, 09 May 2011 18:16:20 +0300, Arie Vayner said:
>>> Actually, I have just noticed a slightly more disturbing thing on the Yahoo
>>> IPv6 help page...
>>> I have IPv6 connectivity through a HE tunnel, and I can reach IPv6 services
>>> (the only issue is that my ISP's DNS is not IPv6 enabled), but I tried to
>>> run the "Start IPv6 Test" tool at and
>>> it says:
>>> "We detected an issue with your IPv6 configuration. On World IPv6 Day, you
>>> will have issues reaching Yahoo!, as well as your other favorite web sites.
>> The *really* depressing part is that it says the same thing for me, on a *known*
>> working IPv6 network.
> FWIW, it is happy with my connection and consistently reports positive results.
> I'm running my own addresses through HE tunnels and tunnels
> to Layer42.
> The tunnels ride over Comcast and Raw Bandwidth DSL.

Yup -- while not perfect, the Yahoo! testing has been working well for me.

Yahoo has to tread a very careful line between giving too little and too much information --  I have tried walking a few non-technical folk through troubleshooting their v6 connectivity by phone and it is really very hard to do, and that is interactively. Writing something that someone can download, print and then follow is nigh impossible. No matter how well this guide is written, a number of folk will manage to screw it up, and of *course* that will be Yahoo's fault....

Jason's page at gives way way more information (and the page at also gives some more), both of these pages are much too complex for the average user.

>> And then when I retry it a few minutes later, with a tcpdump running, it works.
>> And then another try says it failed, though tcpdump shows it seems to work.
>> For what it's worth, the attempted download  file is:
>> % wget
>> --2011-05-09 11:44:39--
>> Resolving 2001:4998:f00d:1fe::2000, 2001:4998:f00d:1fe::2002, 2001:4998:f00d:1fe::2003, ...
>> Connecting to|2001:4998:f00d:1fe::2000|:80... connected.
>> HTTP request sent, awaiting response... 200 OK
>> Length: unspecified [image/png]
>> Saving to: `eye-test.png.1'
>>   [ <=>                                   ] 2,086       --.-K/s   in 0s      
>> 2011-05-09 11:44:39 (154 MB/s) - `eye-test.png.1' saved [2086]
>> Looking at the Javascript that drives the test, it appears the *real* problem
>> is that they set a 3 second timeout on the download - which basically means
>> that if you have to retransmit either the DNS query or the TCP SYN, you're
>> dead as far as the test is concerned.
> Well, if you're having to retransmit those intermittently, then, it does seem you
> have some level of brokenness with your network, no?
> Owen

More information about the NANOG mailing list