DNS Working

What Is the Domain Name System (DNS)?

The Domain Name System (DNS) is often called the “phonebook of the internet”. It translates human-friendly domain names (like www.thejat.in) into machine-readable IP addresses (such as 192.0.2.7).

DNS acts as the distributed database that maps these names to IP addresses.

Computers communicate using IP addresses – a series of numbers. But remembering long numeric for every website would be nearly impossible for humans. DNS solves this problem b allowing us to use easy-to-remember names instead of numbers.

The Problem DNS Solves

Every device connected to the internet has a unique IP address. For example:

• You might try to remember something 192.0.1.1 for Google
• Or 207.0.1.1 for YouTube

Now imagine memorizing dozens or even hundreds of such numbers. It would be extremely difficult – and impractical.

Additionally, IP addresses can change over time due to server updates, load balancing, or infrastructure changes. If you had to remember IP addresses manually, every change would break your access to the website.

DNS as a Phonebook

DNS works much like the contact list (phonebook) on your smartphone.

Instead of remembering someone's phone number, you save it under their name. When you want to call them, you simply search their name and tap to dial – you phone handles the rest.

Similarly:

• You type www.google.com
• DNS looks up the corresponding IP address
• Your browser connects to the correct server
• The website loads

You don't see the IP address – the system handles it automatically.

What Is a DNS Resolver?

A DNS resolver (also called a recursive resolver) is a server that acts like a middleman between your device and the rest of the DNS system. Its job is to find the IP address corresponding to the domain name you typed in your browser.

Think of it like this: You want to call a friend, but you don't know their phone number. You ask a receptionist (DNS resolver) who can look it up in the directory (DNS system) and give it to you.

Where DNS Resolver Exist

1. On Your ISP's Network
   1. Most devices automatically use the DNS resolver provided by the Internet Service Provider (ISP).
   2. This means the resolver is a server maintained somewhere in your ISP's infrastructure, often geographically close to you for speed.
2. Public/Third-Party Resolvers
   1. You can configure your device or router to use external DNS resolvers such as:
      1. Google Public DNS: 8.8.8.8 and 8.8.4.4
      2. Cloudflare DNS: 1.1.1.1
      3. OpenDNS: 208.67.222.222 and 208.67.220.220
   2. These are servers hosted by companies that provide DNS resolution services worldwide.

How a DNS Resolver Works