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Understanding DNS: The Internet's Essential Phonebook

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Omkar Salunke
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What is DNS and Why is it Important?

Imagine you're in India and I want to call your favorite chaiwala, but instead of remembering his phone number, you just remember his name. DNS, or Domain Name System, works similarly—it’s the phonebook of the internet. It translates human-friendly website names like flipkart.com into computer-friendly IP addresses like 192.168.1.1. Without DNS, you'd need to remember long strings of numbers for every website! For example:

  • You type www.amazon.in in your browser.

  • DNS converts it into the IP address of Amazon's server, allowing you to shop for your favorite items.

DNS is crucial because:

  1. It makes the internet user-friendly.

  2. It ensures websites are accessible without needing to remember complex numbers.

  3. It enables smooth communication between devices across the globe.

Types of DNS Records You Should Know

DNS records are like instructions stored in a database that tell your browser what to do. Here are some key types:

  1. A Record (Address Record): Maps a domain name to an IP address.

  2. CNAME Record (Canonical Name): Redirects one domain to another.

  3. MX Record (Mail Exchange): Directs emails to mail servers.

    • Example: Emails sent to @gmail.com go to Google's mail servers.

  4. TXT Record: Stores text information for verification or security purposes.

    • Example: Used for verifying domain ownership in India’s popular payment gateways.

  5. NS Record (Name Server): Points to the authoritative DNS server for a domain.

    • Example: Tells your browser which server has the correct DNS info.

  6. PTR Record (Pointer Record): Performs reverse DNS lookup, converting an IP address back to a domain name.

DNS Hierarchy Explained (Roots to Authoritative)

Think of DNS hierarchy as a delivery chain in India, starting from a central hub and ending at your local post office:

  1. Root Servers:

    • These are the "headquarters" of DNS.

    • They know where to find information about all top-level domains (TLDs) like .in, .com, .org.

    • Example: If you search for irctc.co.in, root servers direct you to .in servers.

  2. TLD Servers:

    • These handle specific domain extensions like .in (India), .com, or .gov.

    • For example, .in servers know where IRCTC’s authoritative server is located.

  3. Authoritative Name Servers:

    • These are the "local post offices" that store actual information about a domain.

    • For example, IRCTC’s authoritative server will return the IP address for irctc.co.in.

  4. Recursive Resolvers:

    • This is your "delivery agent"—usually managed by your Internet Service Provider (ISP) like Jio or Airtel.

    • It fetches data from root, TLD, and authoritative servers and delivers it back to your browser.

Here’s how it works in simple terms:

  • You type swiggy.com.

  • Your ISP’s resolver asks root servers where .com domains are managed.

  • Root servers direct it to .com TLD servers.

  • TLD servers point it to Swiggy’s authoritative server.

  • The authoritative server gives the IP address, and via — you’re browsing Swiggy

How DNS Works - Domain Name System - Digital Varys

Example

Let’s say you want to order food from Zomato (zomato.com):

  1. You type the URL in your browser.

  2. Your ISP (e.g., JioFiber) sends a query to its recursive resolver. is a computer that acts as an intermediary between a user and a DNS nameserve

  3. The resolver checks with root servers, which point it to .com TLD servers.

  4. The .com servers direct it to Zomato’s authoritative server.

  5. The authoritative server provides the IP address of Zomato's website.

  6. Your browser connects you to Zomato, and you start browsing menus!

Why Should You Care About DNS?

In India, where millions access websites daily for shopping, education, or entertainment, DNS ensures:

  • Faster and reliable connections (think of ordering on Flipkart during Diwali sales).

  • Secure browsing with proper configurations like TXT records for email verification or anti-spam measures.

So next time you visit your favorite Indian website or app, remember—DNS is silently working behind the scenes like magic!

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