Linux Small Knowledge translator-"dns Server"

This time chat "dns server".

The DNS (domain name System) server, also known as the domain name server.

Because when using the Internet, you must specify a DNS server, so you must have heard the name DNS.

So, what does this DNS server do?

When connecting to other hosts over the Internet, users typically enter a host domain name like "www.lpi.or.jp".

This domain name is well understood by the user. However, the computer identifies the host of the network through an IP address such as "202.218.212.222".

The task of the DNS server is to establish a correspondence between this domain name and the IP address.

Roughly speaking, the DNS server has 2 main functions:

First, according to the client's inquiry, the domain name is converted to an IP address (or IP address to a domain name), this function is called "full-service Resolver"[fn:2], the client performing this inquiry is called "stub Resolver"[fn:3].

Second, to manage and provide the data corresponding to the domain name and IP address, this function is called "Content Server".

Some DNS servers contain the above 2 features, and some DNS servers contain only the 1 features above.

The construction of DNS is very complex, in a word, the DNS server in most cases, only one is meaningless. In the Internet, multiple DNS servers work together to achieve the purpose of "Domain Name and IP Address Association".

The reason is very simple, the number of connected hosts on the internet is super large, it is impossible to manage all domain names by one DNS server.

Therefore, the DNS server uses a "decentralized management" approach. That is, the domain name and IP address of the associated data is not on a DNS server, but on a number of ~ dozens of servers reside.

That is, "based on the cooperation of multiple DNS servers" to complete the domain name to IP address resolution.

The construction of a DNS server is somewhat difficult, but I think it is easy to understand the concept of "multiple DNS servers running together".