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How many root domain name servers are there? I believe that many inexperienced people are at a loss about this, so this article summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

The root domain name server is the top-level domain name server in the Domain name Resolution system (DNS), and they are responsible for managing the authoritative domain name server address of the top-level domain. As an important part of the Internet infrastructure, all domain name resolution operations are inseparable from them. Below we will analyze why there are only 13 root domain name servers in the world from the perspective of DNS protocol implementation.

At the time of the initial design, the total size of the DNS message was 512 bytes, which was structured as follows:

;; QUESTION SECTION:;. IN NS;; ANSWER SECTION:.518400 IN NS a.root-servers.net..518400 IN NS b.rootMurray servers.net.There; ADDITIONAL SECTION:a.root-servers.net. 3600000 IN A 198.41.0.4b.root-servers.net. 3600000 IN A 192.228.79.201

The first 12 bytes is fixed header information.

QUESTION SECTION (query question section):

Root-label: 00, 1 byte;class, 2 bytes and;the qtype: 2 bytes.

A total of 5 bytes.

ANSWER SECTION (answer part):

Root-label: 1 byte;ttl: 4 bytes;class: 2 bytes;type: 2 bytes;rdlength: 2 bytesnameserver name: aroot-serversnet: 20 bytes.

A total of 31 bytes.

The rest of the record section after that has the same structure as the answer section part, that is:

Root-label: 1 byte;ttl: 4 bytes;class: 2 bytes;type: 2 bytes;rdlength: 2 bytesnameserver name: 20bytes.

But other parts of the record can be compressed by DNS, which will be compressed into 4 bytes, so the other parts of the record have a total of 15 bytes.

ADDITIONAL SECTION

Nameserver name: aroot-serversnet: 20 bytes;ttl: 4 bytes;class: 2 bytes;type: 2 bytes;rdlength: 2 bytes;address: 4 bytes.

But the name field can be compressed to 2bytes, so this part takes up a total of 16 bytes.

So the total bytes are: 12+5+31+16n+15m (n is generally equal to m) = 48+31n=512 bytes

So we get n ≈ 14.968.

So we can actually deploy no more than 15 root servers, coupled with the buffer reserved by the early design, so now there are only 13 root domain name servers.

After reading the above, do you know how many root domain name servers there are? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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