Until today, since I started getting into the depth of DNS some years from now, I always thought that there are 13 major super-computers used as a Global DNS servers which were responsible for caching in all the domain names on the IPv4 and IPv6 internet and that’s all I knew about this matter.
Today I had to review my knowledge on the subject of DNS protocol, BIND server etc. in order to be able to fix an issue with a newly configured BIND dns server. In relation to that I red a bunch of interesting articles online discussing a matters concerning root DNS servers.
Here are two major articles worthy to read:
1. DNS Root Name Servers Explained for Non-Experts – by Daniel Karrenberg
2. DNS Root servers in the World
This blow off the myth about 13 major super-servers running on top of backbones to serve DNS requests online. By the way it’s interesting fact that I’ve learned that myth from some O’reilly’s books that were explaining the Redhat Linux distrubution long time ago.
It could be that long time ago this was true but not anymore!
As of today’s date: Tue Mar 16 17:19:02 EET 2010, there are 425 DNS root servers which are an Internet’s bone today.
Interestingly enough full list of the root servers is available via isoc.org’s website along with many more information on the subject of how root DNSes works, how the DNS is served on the Internet as well as the RFC which explain the proper way to implement a DNS server.
Another wrong idea about Global DNS servers that I kept with me over the years is that most of the root servers are geographically located in USA.
A good proof to this delusion is root-servers.org website which contains a wonderful Google map with pinpointed geographical locations of all root servers .Along with this there is a plenty of extensive information on root DNS servers.
Another misbelief when talking about DNS servers is that the A-root server is the main DNS server in the Global DNS cluster.
Another good reading location concerning DNS Root servers is The DNS Root Name Server FAQ .