What is DNS (domain name server)? (Powercert animated videos)

What is? DNS (Domain Name System)?How it works?

This article is derived from the subtitles of the following video links ：
What is? DNS( Domain name server )？(Powercert animated videos)

In the Internet world , Computers are not like humans , Have a name . They are named after numbers , This is because computers and other similar devices communicate with each other on the Internet , Identification method , Also is to use IP Address . People are used to using names instead of numbers . Whether it's talking directly to another person , Or identify a country , place , Or business , People use names instead of numbers .

So in order to build a bridge between human beings and computers , Make communication more convenient , The network engineering developer developed DNS.

• DNS Convert names to numbers
• DNS Convert the domain name into IP Address

So if you enter a web address into the browser ,DNS Can turn names into numbers , Because computers only know numbers .

For example, you want to go to a website , You need to open the browser , Enter the domain name , Let's take it yahoo.com give an example .

Strictly speaking , You don't have to type yahoo.com To get yahoo The web page of , You can type IP Address , If you already know . But because we are not good at remembering and processing numbers , Especially when there are thousands of Web sites on the Internet , We can enter the domain name directly , And then let DNS Help us transform into IP Address .

Go back to the previous example , When you type in your browser yahoo.com when DNS The server will search its database , Find a match for that domain name IP Address , When it's found , It will convert that domain name into yahoo Website IP Address , When all this is done , Your computer can communicate with yahoo The web server started to communicate , And get its web page .

therefore DNS It's basically a directory , When you want to find a number , You won't find the numbers first , But first find the name , Then you can find the number .

Now let's analyze ,DNS What steps are needed to complete the work ：

1. When you enter in your browser yahoo.com when , If your browser or operating system can't find it in their cache IP Address , It sends a request to the next level , That is to say Resolution server .

Resolution server （ Pathfinder ）

• take IP The address is stored in the cache

2. Resolution server Is essentially your network provider , So when the parser receives the request , It checks its cache , See if there is yahoo.com Of IP Address , If it can't find it , It will then send a request to the next level , That is to say Root domain server .

Root domain server

• The root domain server is DNS At the top or bottom of a class .
• There is a total of 13 Group root domain name server , They are strategically distributed in every corner .
• They are 12 Managed by different organizations .
• Each group of root domain servers has its own unique IP Address

3. When Root domain server Yes, yes yahoo.com Ask for IP Address request , Root domain server Actually I don't know IP What's the address , But I know where to find IP Address , then Root domain server Will Pathfinder Point to the top-level domain name server .com Domain name of , then Pathfinder Would ask Top level domain server Go get yahoo.com Of IP Address .

Top level domain service area (TLD server)

• Stored the top-level domain name IP Some information about the address
• such as . COM/.NET/.ORG

4. This one TLD The server management .com domain name , That is to say yahoo.com Of . When TLD The server Received enquiries yahoo.com Of IP Address time ,TLD The server I do not know! yahoo.com Of IP Address , but TLD Will give Pathfinder Point to the next level , That is, the last level , Primary domain server .

Primary domain server / The server

• Responsible for knowing all domain names including IP Address

5. Again , Pathfinder Will ask Primary domain server yahoo.com Of IP Address , They are the last decentralization , When Main domain name service area from Pathfinder When asked , Primary domain server Will yahoo.com Of IP Address response , Last Pathfinder Will tell your computer yahoo.com Of IP Address , So your computer can get yahoo The web page of .
   

It should be noted that , Once the passer-by receives IP Address time , It will store it in the cache , So that the next time yahoo.com Access to use , So you don't have to go through so many steps again .