Google launches DNS service [Updated]
The title of this blog sounds like a news item, and it kind of is. What I’ve just found on the Net: Google is launching their own version of DNS. DNS stands for Domain Name Server, and is responsible for translating a web address (for example www.michielvdvelde.nl) to an IP (Internet Protocol) address (for example 80.84.236.164), which is then used to access the server the web site is running on.
In the past, there have been several leaks and security issues with DNS (according to Wikipedia, DNS was not designed with security in mind). Recently there was a large leak found that would allow a malicious person to poison the cache of a DNS server, redirecting traffic to another computer.
Google attempts to rectify those mistakes, as well as provide a DNS caching system which would speed up DNS requests. This comes from Google’s blog announcement:
The average Internet user ends up performing hundreds of DNS lookups each day, and some complex pages require multiple DNS lookups before they start loading. This can slow down the browsing experience. Our research has shown that speed matters to Internet users, so over the past several months our engineers have been working to make improvements to our public DNS resolver to make users’ web-surfing experiences faster, safer and more reliable.
Using the Google Public DNS
Google’s Public DNS servers are available with IP addresses 8.8.8.8 (primary) and 8.8.4.4 (secondary). If you’re curious and want to use the Public DNS system Google has set up, they provide a how-to on their web site.
I will try out their DNS service and give you a detailed review later. For me, it sounds interesting, but I am a little skeptical as redirecting your DNS traffic to Google provides them with even more information about you than they already have, but Google says not to worry. Right. We’ll see how that turns out in the future, though.
Update: DSN resolve time comparisons
I ran a quick DNS resolve time comparison in the command prompt to see what was faster; the Google DNS or my ISP’s (my Internet Service Provider is Het Net aka KPN (from the Netherlands)).
For the test I used nslookup and the domain I used was google.com. I only ran it ten times for each of the four DNS IP addresses (primary and secondary for both sources), but it should still provide us with some information as to the speed of the Google Public DNS when compared to my ISP’s default DNS servers. Below a scheme of my findings:
The result of the DNS resolve time comparison I ran
As you can see, the average values for both primary DNS servers lay quite close together, but Google appears to be faster. The secondary DNS servers are significantly slower than the primaries, and the difference between the two is also larger.
When it comes to the primary DNS server averages, Google wins by a hair (only 3 milliseconds). With the secondaries, my ISP’s DNS servers beat Google’s by as much as 18 milliseconds.
The DNS resolve time comparison displayed in a graph
In all fairness, I have to say that my ISP’s DNS servers are most likely (actually: definitely) located closer to my location than Google’s. So depending on where you live, this comparison might not be applicable to you. With that in mind, it can be said that the Google Public DNS is faster, because its packets (requests and responses) have to travel further along the Internet highways.
Still, for people living in the Netherlands and having Het Net (which shares its DNS servers with KPN, as it technically now ís KPN), it might not make a difference for you. I will use the Google DNS myself for the time being, and I will report more about this in a future post. I am especially interested in comparing the Google times with the times of other DNS providers around the world, so if you want to help me with this, please comment on this post (with a valid email address) and I will contact you!
Updated the results for a stupid mistake on my part; all values were a power of 10 greater. My apologies.
Geaographical coverage – added 5/12/2009
I did some more reading on the subject, and found an interesting piece of information that basically voids my conclusion that Google Public DNS might be faster due to the locations of the servers. This is from their web site:
Google Public DNS is hosted in data centers worldwide, and uses anycast routing to send users to the geographically closest data center.
Like I said, this voids my conclusion that the Google DNS might be faster than my ISP’s because of the distance between me and the server(s), at least to some extend. Google follows with the next disclaimer:
Note, however, that because nameservers geolocate according to the resolver’s IP address rather than the user’s, Google Public DNS has the same limitations as other open DNS services: that is, the server to which a user is referred might be farther away than one to which a local DNS provider would have referred. This could cause a slower browsing experience for certain sites.
So it doesn’t completely void my conclusion, but it does decrease the potential gain of the Google Public DNS, at least in the Netherlands. I am writing a script that will allow me to measure DNS resolve times for a host of ISPs (mostly from the Netherlands), as well as OpenDNS, so I should be able to provide a detailed performance report in a few days.