Google Public DNS Problems?

Joe Abley jabley at
Thu May 2 16:10:40 UTC 2013

On 2013-05-02, at 11:59, Charles Gucker <cgucker at> wrote:

>     That's not entirely true.    You can easily do lookup for
> and it will return the unicast address for the node
> in question (provided the local resolver is able to do the
> resolution).    This is a frequent lookup that I do when I don't know
> what actual anycast node I'm using.

Using to tell me about tells me what Akamai authoritative server Google last used to answer that query.

If I can rely upon there being an Akamai auth server every place there's a Google server, then that does seem fun and useful for identifying the Google node I'm using. Is that the case?

(If I ask, which is somewhere 30ms from Toronto, about then the answer I get just now is "Paris, France". L-Root and Google/ are not colocated. So the usefulness of this technique in general to identify Google nodes depends on deployment assumptions.)


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