Drinking with a friend, he told me how his lecturer had revealed to his class that the US can turn off the Internet for the whole world if it wants to, because all of the DNS root servers are there. I wasn't convinced, because that would go against the decentralised nature of the Internet, and generally it sounds like a poor idea.

Now, I've seen TV programmes where some lad stands in a DNS server room saying "without this the Internet would break", but that sounds exaggerated.

The Wikipedia Root Name Server explains that there were once 10 DNS servers in the US, and that was it, but now they're distributed using Anycast - which is a distributed system.

I also found this interactive map which shows dozens of root servers around the world.

Map showing root servers

So what's the story? Have the worlds internet folk built a distributed DNS system which no one country can disable for the rest of the world? Does my friend's lecturer need to go back to school?

Or is this whole system, which looks remarkably robust, still relying on the USA?

  • Routing and Resolving of addressing will take time if there are less DNS servers. USA will never do that. It will affect their communication first then others. Your friends comment was an overstatement. – John Jan 30 '12 at 13:33
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    "USA will never do that" - certainly not the USA as we know it, but it's a question of capability rather than tendency. – puppybeard Jan 30 '12 at 15:00
  • Pakistan managed to block access to YouTube for the whole world for a brief period of time. – Andrew Grimm Jan 31 '12 at 10:28

http://en.wikipedia.org/wiki/Domain_Name_System Without name servers the DNS would not exist. But that's not the end of the internet, it's just the end of easy communication without having to remember sequences of numbers as addresses rather than words.
And of course the US can't (as you all but pointed out) shut down the DNS as they don't control all the DNS servers in the world (heck, any ISP and most larger companies run their own, you can run one in your own home if you want to). At most they can make things more inconvenient, slowing down traffic as routing tables need to adjust to make up for the servers that are no longer online in the network (that's easily deduced from the entry you list).
As to relying on the US or not, that depends on what you mean by the word. The internet as a whole can survive the destruction of its entire US component (including all the cables and other transmission hardware), but some places might be cut off from the rest of the world and be unable to access sites elsewhere (with the rest of the world being unable to access sites in the cut off areas. That's however got nothing to do with the DNS system but relies on the backbones, the individual data pipelines (usually underseas cables and/or high speed satellite connections) between major data hubs. This system was designed to be redundant, so that any part of it failing would have minimal long term impact on the rest. I've not been able to find a picture of the entire infrastructure.

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    "The internet as a whole can survive the destruction of its entire US component" that's the glaring problem. For it to be any other way would be to suggest that decentralisation, the main goal of ARPANET, (the forerunner of the internet, as most of us know) has been ignored by the whole world. – puppybeard Jan 30 '12 at 13:50
  • @puppybeard Your second link shows the answer well - the most immediate issue of the US disabling their DNS servers would be the US becoming cut off from the rest of the world. – Rory Alsop Jan 30 '12 at 18:19
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    @jwenting - you cant find a picture of the entire infrastructure because it is a crazy mess of fiber, and servers owned by literally thousands of different entities. I worked for an ISP in 1995. At the time we had a book that we could use for advanced routing. The book was a 3 inch binder (full) and it only covered those major backbones where through routing was permitted with our license. The number of back bone connections would triple over then next 2 years and then again the year after... Then in 1998 the internet really took off. – Chad Jan 30 '12 at 19:35
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    1) No-one said they own all the DNS servers in the world. They said they own all the Root Name servers. 2) You haven't shown that blacking out the USA will blackout any particular country. Citation needed. – Oddthinking Jan 31 '12 at 4:30
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    @Oddthinking I don't claim it will happen, just that it MAY happen (e.g. if a specific country has only a single backbone link with the world and that link runs through the US, maybe some Caribbean island). – jwenting Jan 31 '12 at 6:16

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