What is DNS?

Admin
23 Nov, 2023

What is DNS - DNS (Domain Name System) converts a domain name (like example.com) to an IP address (like 104.239. 197.100). 

For example, when a web address (ie a URL such as programmingstech.blogspot.com) is typed into a browser, the DNS server returns the IP address of the web server associated with that name that the browser uses to load the web page. Are. 

So, this was the basic information about DNS, if you want to know about it in detail then you keep reading this article further because in today's article, we will know in detail what is DNS? How does DNS work? And how does DNS find an IP address and direct us to a website?

DNS

What is DNS?

Definition - The full form of DNS is a Domain Name System. The function of DNS is to convert the domain name typed by the user into an IP address.

Every website has its own unique IP address. When you enter the domain name of a website in the web browser, DNS provides the IP address of that website.

Example -: When you type a domain name like google.com in your web browser, it is converted into a valid IP address like 197.51.67.87 or similar through DNS.

Providing the IP address of the domain name through DNS is also important because, without the IP address, we will not be able to access that website. All web browsers on the Internet work through IP addresses only.

There are many numbers present in the IP address which is difficult to remember but it is quite easy to remember the domain name of the website. But to access the website through the domain name, we need the IP address of this domain name which provides us with DNS. 

DNS can also be considered as the phone book of the Internet. Because it contains a database of unique IP addresses of all domains. 

Although now there are many websites in the world, will the IP address information of all these websites be stored in a single DNS server? No, this is a difficult thing to do and is also not advisable from a security point of view.

Just as the Internet is spread all over the world, there are many Domain Name servers spread all over the world where information is stored.

All these servers are connected to each other. If information is not found in one DNS, it automatically contacts another DNS and obtains the information.

DNS eliminates the need to remember IP addresses and enter a large number of IP addresses into a web browser. Instead, you can enter a domain name like example.com and then access that website or webpage.

History of DNS

About 40 years ago, when the Internet was very little used, the number of websites was limited. This made it easy to remember the IP address. But as the Internet gradually expanded, so did countless websites.

Now it is not possible to remember the IP addresses of so many websites. To overcome this problem, a computer scientist named Paul Mokapatris developed DNS (Domain Name System) in 1980.

After the advent of DNS, people only had to remember domain names. As we type a domain name into a browser, DNS converts it into an IP address and takes us to that website.

What is Public DNS?

Public DNS is available to everyone. Anyone can access the website present in this DNS through the internet. In this DNS everyone can see and access the IP address of your website.

What is Private DNS?

Private DNS is a little different. Not everyone can use it. This DNS is behind the company's firewall, in which only the records of the internal site are stored. Private DNS is often used by those people who have to show their website only to a limited number of people. For example – when you login to a website to do your work, no one can access it, because your information is stored in the internal site of the company.

How does DNS work?

All the devices that are connected to the Internet have their own unique IP address. DNS converts the domain name typed by the user in the browser into an IP address, through which you access that website.

After the advent of DNS, you do not have to remember the complex IP addresses of all the websites. You only have to remember the domain name, which is quite easy.

When we search for a domain name like Google.com on our web browser, the Internet does not understand this language. It understands only the language of the IP address, and it communicates in it. If you type the IP address of the website instead of the domain name, you can still access that website. But there are many numbers present in the IP address which is very difficult to remember. This is why we use domain name to visit any website.

DNS is the phone book of the Internet, which contains a database of unique IP addresses of all domains. When you type in a domain, DNS finds the correct IP address and takes you to the website.

There are many steps in DNS to find the IP address of a website, in which first the domain name is converted into machine language i.e. IP address so that the server can understand which website you have to go to. 

When you search a website on the Internet, all the IP addresses related to that domain name are mapped and after finding the correct IP address, the website is loaded in the browser. This process of mapping IP address to domain name is called DNS resolution.

Types of DNS Server

1) DNS Resolver Server   

It is also called a resolver. It is a server in the Internet which converts domain name into IP address.

2) Root Server 

When you type a domain name in the browser, the root server is the first step in the process of converting it into an IP address.

3) TLD (Top Level Domain) Server 

The name after the dot (.) at the end of any domain is called TLD (Top level Domain). It searches for a specific address that hosts the last part of the domain. For example – in www.google.com “.com” is called TLD.

4) Authoritative Name Server 

The data of IP addresses of all websites is stored in this server.

How does DNS direct us to the website by finding the IP address?

  1. When a domain name is typed in the browser, the browser first searches the IP address of that domain in its cache memory, because if the website has been opened before, it will be stored in the cache memory.
  2. If the IP address is found in the cache memory of the web browser, the website opens.
  3. But if the IP address is not found even in the cache memory, it sends a request to your device's operating system like Windows, Android and Mac.
  4. After this, the operating system sends this request to the ISP (Internet Service Provider). Who has an IP address stored.
  5. If the IP address of that website is found then the process ends here and the website opens.
  6. If there is no IP address found then the resolver transfers the request to the root server.
  7. The root server forwards this request to the top-level domain. TLDs are like .com, .gov, .org, .edu etc. The requested website is connected to the same TLD server. If the request is from Google.com it will connect to the .com TLD server.
  8. Now finally after obtaining the information from the top-level domain server, the information about the actual name server is obtained from the authoritative name server, from where the IP address of the domain is known.
  9. After receiving the IP address of the website, it is sent to the client, i.e. your computer or device, which is saved in the cache memory of the browser so that you do not need to repeat it the next time you type the same website.
Although this seems like a long process, it happens so quickly that we don't even realize it.

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