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John Kozubik

Review of the performance documentation, located here:


neither bolsters nor negates my contention that Google will use their DNS as an adjunct to PageRank, and thus "discourage" caching.

On the one hand, they (rightly) point to "(t)he trend towards lower DNS TTL values" and "cache isolation", but their solution to this is simply to accept these trends and throw more hardware and geographic redundancy at the problem - which is easy, if you're Google.

On the other hand, Google is going to be prefetching name resolution. Their explanation is a bit hazy, but it does not stand to reason that search results will be more relevant based on prefetched name lookups...

So, in addition to examining the default cache settings for name resolution in things like Chrome and Android, I'd also like to see how a "normal" name lookup is formed vs. a prefetched lookup. My contention would imply the ability for Google to distinguish between the two...

Chris Carlin

As if the ISPs that are serving the DNS queries are any better?

I'd say at least Google is in a position to do something positive with the data. And in the end, using Google for DNS is a choice that a user could unmake pretty easily if he's not being served well... the default ISPs have far more propensity toward evil with their semi-captive audiences.

I'd say Google's plan is the best of evils in this case.

John Kozubik

Well, the point of the above post was not to focus on whether Google Public DNS is a good or a bad thing ... I think it's bad, from the point of view of Internet monoculture, but that's really just an aside ... or a personal comment.

The point here is that I have yet to hear a plausible rationale for the existence of this service, other than a very hazy "google aggregates a lot of data and somehow makes money off of that".

So, the point of the post was what I believe to be a plausible rationale. I think they are going to start to adjunct PageRank with "out of band" data to improve search relevance.

If you want to delve into the infrastructure ramifications of the service, the NANOG link I posted contains a thoughtful discussion.

Account Deleted

Your rationale is bogus. Try reading the Privacy page for Google Public DNS. It clearly states:

We don't correlate or combine your information from the temporary or permanent logs with any other data that Google might have about your use of other services, such as data from Web Search and data from advertising on the Google content network.

Account Deleted

Also, I tried reading that NANOG thread, but gave up after 10 or so messages about silly not-very-funny jokes :-(.

John Kozubik

I don't think the privacy policy in any way precludes Google from using DNS trails to provide "better" search results to the public at large.

If some random web browser shows up and searches for "widgets" and Google has noticed that people who nslookup this widget site tend to also nslookup sites X, Y and Z in some connected fashion afterwords, then Google can adjunct PageRank with that information.

That's not disallowed by the privacy policy. They wouldn't be combining the data with "other data that Google might have about your use of other services" - they would be combining it with PageRank to generate new search results for the public at large.

(never mind how much trust we should place in their privacy policy - let's assume for the sake of discussion that it is never diluted and always enforced)


I think the actual reason behind Google's move is that it should make Chrome (and by extension, Chrome OS) slightly faster.


If Chrome is doing DNS pre-resolution to make things seem faster then they probably want to make sure that DNS requests are handled as quickly as possible. My bet is that Google figured that the best way to speed up DNS was to host it's own DNS service.

I have to admit, when I switched over to Google's DNS Chrome was ever so slightly faster (though Firefox 3.0 remained about the same). While it's only a slight improvement, Google is trying to make the fastest browser and every slight improvement helps.

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