There are more than 13 root servers. Much more.

Many people talk about root servers, domain names, IP addresses, and these words sometimes sound like a secret society codes. Here’s an explanation of the number of root servers. Some people claim that the root servers are “controlled by the US Government”, and that this “control” means the US government (the “evil American imperialists”) can shut down the Internet in any given country, or even in the whole world, because they have the root servers under their (governmental) control. (by the way, I am not one of these people; just find it interesting to quote)

Kim Davies of IANA wrote this last week trying to explain how the root servers work:

I am at the UN Internet Governance Forum, being held this week in Rio de Janeiro, Brazil. A recurring theme you can hear here is one that has vexed the technical community many times before — “Why are there 13 root servers?” This question is usually followed by questions like “Why are most of the root servers in the US?”

So let’s dispel these myths.

There are not 13 root servers.

What there are is there are many hundreds of root servers at over 130 physical locations in many different countries. There are twelve organizations responsible for the overall coordination of the management of these servers.

So where does the 13 number come from?

There is a technical design limitation that means thirteen is a practical maximum to the number of named authorities in the delegation data for the root zone. These named authorities are listed alphabetically, from a.root-servers.net through m.root-servers.net. Each has associated with it an IP address (and shortly some will have more than one as IPv6 is further rolled out).

But when we think of servers, we probably think of physical machines that sit on a desk, or perhaps lined up in racks in a specialized computing facility. By any measure, there are not 13 servers as there is not a correlation between the number of named authorities, and the number of servers.

The majority of named authorities are spread across multiple cities, often multiple countries. The “I” root, for example, is located in 25 different countries. But ignoring the physical diversity, even those authorities that are just in one physical location — the reality is they are comprised of networks of multiple servers that handle the millions of DNS queries the root servers receive every hour.

Another thing you may hear is that some of these root servers are just copies, whilst others are the “real” name servers. The reality is that every single root server is a copy, and none of them are more special than the others. In fact, the true master server from which the copies are made is not one of the public root servers.

So next time you hear there are 13 root servers, or that they are mostly in the US, just remember this map, courtesy of Patrik F?ltstr?m:


View Larger Map

Note from Veni: There is one such a server in Bulgaria. I blogged about it last year. That makes Bulgaria again on the cutting edge of technology, and I am quite happy to be able to contribute to this happening.
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Wikipedia gives this explanation:
No more names can be used because of protocol limitations – UDP packet can only carry 512 bytes reliably and a hint file with more than 13 servers would be larger than 512 bytes – but the C, F, I, J, K, L and M servers now exist in multiple locations on different continents, using anycast announcements to provide a decentralized service. As a result most of the physical, rather than nominal, root servers are now outside the United States.

4 thoughts on “There are more than 13 root servers. Much more.”

  1. And Athenian one at Omonia square? Hard to believe.

    Anyway, it is good to know that the Force is equally distributed.

    Your blog is great, and we all know you’re one of the keepers of the Force.

    Stefan

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