Google Public DNS
December 6th, 2009
Google announced Google Public DNS a few days ago.
I don’t really understand why I’d want to use it or why this project is a good idea for Google, but now we have one more DNS server for testing purposes that has an IP address that is easy to remember :-)
December 6th, 2009 at 5:10pm UTC
It’s quite simple – officially you try to improve the response time by reducing the time for lookups. Under the table this is also fighting the increased DNS redirect mechanisms implemented by large ISPs. Controversial, to say the least.
December 6th, 2009 at 9:26pm UTC
@wnagele: I did some unscientific tests with dig and for me it’s not faster. I used my local NAT DNS resolver that is set by default on my local network and compared it with response times from 8.8.8.8 with domains I usually don’t lookup (so there won’t be any cache hits).
Lookups with cache hits were faster than cache misses, but 8.8.8.8 was always slower than my local NAT DNS resolver. Don’t ask me how this local NAT DNS resolver works inside of my router and how the caches will actually behave.
December 7th, 2009 at 1:15am UTC
This was probably exactly the wrong test. The system (reading the FAQ) is aiming to especially speed up frequently requested sites by re-caching them automatically without any client needing to request for them. That’s all nothing new really and is only in the media because G is doing it. But requesting something not cached will most likely show worse results then your local resolver because of the added round-trip between the G-resolvers and you. That’s however something you can scale pretty well using Anycast these days, but i guess that’s something for later.
Anyway, i guess you’d be surprised how many ISPs out there have a fucked up resolver running for their customers. And i guess that is the clients that this service is aiming at, besides the redirected customers of some major ISPs. :)
December 7th, 2009 at 6:50pm UTC
@wnagele: But isn’t there a high probability that a frequently requested site will be in the DNS cache of my ISP anyway? :-)
December 7th, 2009 at 7:54pm UTC
jup … but that’s all about definition of frequently and the user base of the cache