Here at ThousandEyes, we’ve always been curious about the performance of various public DNS resolvers — especially since Google threw their hat in the ring back in 2009. We satisfied our curiosity this week, so we thought we’d share the results.

Here’s how we did it. We measured the latency to each resolver from approximately 3000 points around the globe with a minimum of 50 points per country. This means that these results are based on the best-case resolution time, assuming you tried to retrieve a DNS record that was in the public resolver’s cache. The results shown are the average over a 24-hour period.

Using this data, we determined which DNS provider’s resolvers were fastest (on average) as seen by each of the vantage points. We picked a winner per country based on the provider that was most frequently the fastest in that country. The map below is colored accordingly. As you can see, if you are in the US, chances are that your fastest public resolver is an OpenDNS resolver. But if you’re in India, it’s probably Google.

Fastest DNS providers per country, UltraDNS (yellow) applies to Hong Kong.

Global Results:

United States Results:

Most regions have a clear frontrunner — OpenDNS in North America, Central America, and Africa, Google in South America and the Asia-Pacific region, and Dyn in eastern Europe. In western Europe, however, there is a bit more contention for the top spot, with each of the top three providers making a strong showing. At a country level, Level3 DNS resolvers did not make it to the top anywhere while Ultra’s DNS resolvers made it to the top in Hong Kong (though you can’t see it on the map).

Now that our initial curiosity about the performance of different public DNS resolvers has been satisfied, our next task is to understand how the performance of public resolvers compares to the default resolver provided by your local ISP. That’s definitely more involved and will be the subject of an upcoming article.