Q.What is DNS?

The Domain Name System (DNS) is the internet's phonebook. It translates human-friendly domain names like google.com into machine-readable IP addresses like 142.250.183.78. Without DNS, you would have to remember long strings of numbers for every website you visit.

Here is how it works in a nutshell:

• When you type a URL into your browser, your computer first checks its local cache.
• If the address isn't cached, it queries a DNS resolver (usually provided by your ISP).
• The resolver then asks a series of DNS servers — starting from the root server, then the Top-Level Domain (TLD) server (like .com or .org), and finally the authoritative name server for that specific domain.
• The authoritative server returns the correct IP address, and your browser loads the site. …

Think of the internet as a vast city. Every building — every website, every server — has a precise street address: an IP address, a string of numbers like 192.0.2.1. Humans are terrible at remembering long strings of numbers. We remember names: "Google," "YouTube," "NCERT." The Domain Name System, or DNS, is the service that bridges this gap. It is a distributed, hierarchical database that maps domain names to their corresponding IP addresses.

When you type a website address into your browser, your computer doesn't know where to go. It first asks a DNS resolver — usually run by your internet service provider — "What is the IP address for example.com?" The resolver then begins a chain of queries. It asks a root server (the top of the hierarchy) where to find the .com nameserver. The root server points it to the .com nameserver, which in turn points it to the authoritative nameserver for example.com. That final server holds the actual IP address and sends it back. Your browser then uses that IP to connect to the website's server and load the page.

DNS is not a single computer. It is a global, distributed system. This design is crucial: if one server fails, others take over, and no single point of failure can bring the entire internet down. The hierarchy — root, TLD (top-level domain like .com, .in, .org), and authoritative nameservers — ensures that the load is spread and that every domain can be found efficiently.

A lookup can happen two ways. In a recursive query, the resolver does all the work on the client's behalf and returns just the final answer. In an iterative query, each server in the chain returns only its best next pointer, and the resolver itself follows the chain step by step. Most home devices only ever see a recursive query — the multi-step chase happens between the resolver and the DNS servers, invisibly. …