Hi,

I accidently had fiddler web debugging tool active while doing a search in google and noticed a wierd request to going to

http://o-o.resolver.o.[MY_IPADDRESS].[HEXID].l.google.com/gen204

The google server replies to it with a :

HTTP/1.1 204 No Content
Date: Fri, 02 May 2008 09:33:14 GMT
Content-Type: text/html
Server: gws
Content-Length: 0

The request occured from a search search result page ending like :

©2008 Google</font></center><link rel=prefetch href="http://o-o.resolver.o.[IPADDRESS].[HEXID].l.google.com/gen204"></body></html>

It doesnt seem to be doing it on every page and i have only so far being able to see it happen that one single time. I'm guessing it's inserted randomly to a few requests.

Only thing I can guess from that is that google is trying to figure out which dns server the user is using to resolve their domain name. Perhaps to optimise the location of the dns servers?

Doing a search for "o-o.resolver.o .google.com" on google

reveals several squid log files containg similar request (with different ip's and hex ids) but nothing else. There doesnt seem to be any information about them.

I was wondering if anyone else here has seen it themselves. Or else knows anything else about it.