Technology Internet

What is DNS and how does it work?


In the internet world, devices do not go by names; they go by IP addresses! Domain Name System helps you to visit or search websites through domain names. When you search any website, then DNS matches the domain name with the server’s unique ID where that website is hosted. In simple terms, DNS resolves domain names to IP addresses.

DNS works the same as your phonebook, where you save the contacts. In the phonebook, you write a contact number with the name of that particular person. Same like that, DNS records website names with their identifiers called IP addresses.

A brief history of DNS

At the starting of the internet, it was very easy for people to remember specific IP addresses for a particular computer. As the internet grows, more people and devices are making the internet more vast and complex. Now, it’s impossible to remember a huge number of IP addresses.

However, it was simple to type the IP address of any specific website to connect with that website, but gradually people started asking for an easy to remember words that can be recognized uniquely.

In the early 80s, only one person assigned those addresses and maintained a list of devices on the internet. His name was Elizabeth Feinler, who listed all the IPs of internet devices in a text file known as Hosts.txt. As the internet grew, it was impossible to create a complete list of devices on the internet. In 1983, researcher Paul Mockapetris developed a new system named DNS. Till then, DNS is working almost in the same way as it was working 38 years ago.

How Does DNS Work?

The internet is a collection of massive networks of devices. In this complex network, every device is recognized by its unique IP address. An IP address has four fields, and each field has 8-bits that are separated by periods. For example, is an IP address in which the bytes are represented in dotted-decimal format.

If you have to connect a website by searching an IP address instead of that website’s domain name, imagine how difficult it is to remember that IP address. You can’t visit many websites because it’s difficult to remember IP addresses. Thanks to DNS, they translate domain names and lookup for the IP address against that name, and connect to the website.
The domain name was introduced to let users select and easy to remember names for their websites.

Now, let us discuss the working of the domain name system in simple steps.
Let’s suppose if we want to connect a website through the domain name, when you type any website name and hit enter, then it will first run a check to see whether you visited that website previously or not. If your device’s DNS cache has that website, then it skips the rest of the DNS process, and you will be directed to that website.

If you did not visit that website previously, it wouldn’t get that website in your DNS cache. In this case, the request is sent to the resolving name server. Resolving name server is your internet service provider that gets the query and looks up for that website in its DNS cache, and sends a response if it gets that website in its DNS record.

If the ISP server did not find that website, it sends a request to the root name server. Root name servers are placed at the root of the DNS hierarchy responsible for storing DNS data and managing system working. There are 13 sets of root servers placed strategically all around the world. If the root server does not find that specific IP address, it directs the name server or resolver to a top-level domain (TLD) server by providing the server’s IP address.

Top-level domain server stores information for top-level domains such as .com, .org, .net, etc. If we search the .com domain, then a particular TLD manages that request. If the TLP address does not have the IP address of that website, it directs the resolver to the final level.

Now the request will be sent to Authoritative name servers, and this server is responsible for having all the IP addresses. When it gets the IP address of that specific domain name, it sends IP to the resolver, and then the resolver stores that record into its DNS cache and sends it to your PC. After this process, you can access that specific website!

Bottom Line

DNS stands for domain name system that resolves any website’s domain name into an IP address. The need is to identify any device with a unique number, and the IP address does the job well. As the internet expanded, people found it difficult to remember IP addresses to reach any website. To solve this problem, Paul Mockapetris introduced DNS.

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