I’ve been a big fan of Google’s services for many years. GMail, Google Calendar, Google Talk, Google Voice, and Google Docs are all a regular part of my day. (Admittedly, I haven’t quite figured out how I’ll use Google Wave, but I’m sure there’s a use for it somewhere.) So when I heard about Google offering a DNS service, I was very interested. DNS (the Domain Name Service) is a vital part of the Internet. It is what allows people to visit Funnel Fiasco without having to remember that the IP address is 188.8.131.52. Or to visit www.facebook.com without typing in 184.108.40.206.
A while ago, I switched from using my ISP’s DNS service to OpenDNS. OpenDNS gives users the option to filter domains by content, which is a somewhat useful tool for parents and businesses. Unfortunately, OpenDNS, like most ISP DNS services, returns a search page when a domain isn’t found. Sure, that might be handy for web browsing, but other services expect to be told a domain doesn’t exist when it doesn’t exist. Google said that they’ll return appropriate responses for non-existent domains.
Before I made the switch, I decided to investigate which DNS service gave me the fastest responses. I tested 8 DNS servers from 4 different services (Google, Comcast, OpenDNS, and Level3) at different times over the past few days. The final result surprised me. Google’s service was slower than both Level3 and OpenDNS, and slower than one of the two Comcast servers I tested. Box plots are below, although it seems some of the calculation is off (for example, a DNS resolve time < 0 ms is not reasonable).
Average hostname resolve times in milliseconds
So what’s the conclusion? Well, it looks like the Level3 servers (220.127.116.11 and 18.104.22.168) are the fastest. Tests by intMain.net support my own conclusions. Google’s DNS service might be faster for some people, but not for everyone. If Google adds more servers, that might change. In the meantime, it looks like I have some resolv.conf edits to make.
(P.S. Box plots created thanks to software from Vertex42.com)