What is Domain Name System (DNS)?

In this session, we will learn about the concept of Domain Name System (DNS), why it is used, components, and operating principles.

 

 

1. What is DNS?

 

 

When we use the Internet to search, surf the web, or e-mail, we enter the domain name (www. Naver.com) in the address bar of the web browser and access Naver.

 

In other words, the actual naver.com server communicates with an IP address composed of numbers, but we need to use an easy-to-remember domain name and then convert the domain address (www.naver.com) we entered into a numeric IP address, and the system in charge of this is DNS.

 

 

 

 

 

 

 

2.  Why DNS ?

 

 

To be honest, no one would enter the Google IP address directly into the Internet window to access Google, right? Even if there is, there will be no one who memorizes and remembers the IP addresses of many sites.

 

Because you cannot memorize long and complex IP addresses, you will use DNS to use text addresses.

 

 

 

 

 

 

3. Components and Principles of Operation

 

 

① Domain Name Space

: The root DNS server exists at the top, and all nodes connected to the Internet are organized in a continuous hierarchy.

 

 

② Name Server (Name Server)

: Information on the tree structure of the domain namespace is required to translate addresses. Name service to convert server domain names with this information to IP addresses

 

 

③ Resolver

: It delivers DNS client requests to the name server and receives domain names and IP addresses from the name server and provides them to the client.

 

 

 

< DNS operating principles>

Domain names have a specific order.

 

Name by service is located, expressed in order of organization type, country name.

 

Kr

: A domain defined for each country's use and based on the country code defined in ISO 3166 [4]

 

com

: Domain for commercial organizations such as enterprises

 

edu

: Domain for educational institutions

 

 

net

: Domain for systems related to network service providers

 

 

org

: Domains for non-governmental organizations that do not belong to other TLDs.

 

 

int

: Domain for organization created by international conventions

 

 

GOV

: Originally a domain for government agencies or organizations, but decided to register only the federal government, including the current state government of the United States.

 

 

mil

: Domains defined for use by US Department of Defense agencies

 

 

arpa

: Special domain used to map IP addresses to domain names

 

 

 

★ DNS operation process

1. DNS Query (from Web Browser to Local DNS): "Do you know the IP address of the website I want?" Delivered to the Local DNS server.

 

2. DNS Query (from Local DNS to Root DNS): "Do you know the IP address of the website I want?" Delivered to the Root DNS server

 

3. DNS Response (from Root DNS to Local DNS): "I don't know, but I'll tell you the name and IP address of the name server that manages the Com domain, so please ask there."

 

4. DNS Query (from Local DNS to com NS): "Hello. Do you know the IP address of www. naver.com?"

 

5. DNS Response (from com NS to Local DNS): "I don't know, but I'll tell you the name and IP address of the name server that manages the Com domain, so please ask there."

 

6. DNS Query (from Local DNS to naver. comNS): "Hello. Do you know the IP address of www. Naver.com?"

 

7. DNS Response (from naver.com NS to Local DNS): "I don't know, but the web goes by the name www.g.naver.com. "I'll give you the name and IP address of the name server that manages the g.naver.com domain, so please ask there."

 

8. DNS Query (from Local DNS to g.naver.comNS): "Hello. Do you know the IP address of www.g.naver.com?"

 

9. DNS Response (from g.naver.com NS to Local DNS): "Yes, www.g.naver.com's IP addresses are 222.222.222.22 and 333.333.333.33"

 

10. DNS Response (from Local DNS to Web Browser): "Yes, www. naver.com's IP addresses are 222.222.222.22 and 333.333.333.33"

 

I've learned about many things in DNS. Even if you don't know the depth, please be familiar with the concept.

 

 

 

 

 

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