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Manoj Kumar
Manoj Kumar

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how DNS resolver is happening

#webdev #beginners #tutorial #networking

🌐 How DNS Resolution Happens (Simple Step-by-Step Guide)

Hi everyone 👋

Whenever you open a website like google.com, it loads instantly.

But have you ever wondered… how does your system know where that website actually exists? 🤔

That’s where DNS resolution comes in. Let’s understand it in a simple way 👍

📌 What is DNS?

DNS (Domain Name System) is like a phonebook of the internet.

👉 It converts:

google.com → 142.250.183.206
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  • Humans use domain names
  • Computers use IP addresses

💡 What is a DNS Resolver?

A DNS Resolver is the system that finds the correct IP address for a domain.

👉 It acts like a middleman between:

  • Your device (client)
  • DNS servers

🚀 Step-by-Step DNS Resolution Process

Let’s see what happens when you type a website in your browser.

🔹 Step 1: User Enters URL 

www.example.com
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👉 Your browser starts the DNS lookup process.

🔹 Step 2: Check Browser Cache

The browser first checks:

  • “Do I already know this IP?”

👉 If yes → use it directly

👉 If no → go to next step

🔹 Step 3: Check OS Cache

Your operating system also stores DNS records.

👉 If found → request is resolved

👉 If not → continue

🔹 Step 4: Contact DNS Resolver

Now the request goes to a DNS Resolver (usually provided by your ISP or public DNS like Google DNS).

👉 This resolver will do the hard work for you.

🔹 Step 5: Root DNS Server

Resolver asks the Root Server:

👉 “Where can I find .com domains?”

Root server replies:
👉 “Ask the TLD server”

🔹 Step 6: TLD Server (Top-Level Domain)

Resolver asks the .com server:

👉 “Where is example.com?”

TLD responds:
👉 “Ask the Authoritative Name Server”

🔹 Step 7: Authoritative Name Server

This is the final source.

👉 It gives the exact IP address:

example.com → 93.184.216.34
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🔹 Step 8: Return to Client

  • Resolver sends IP back to your browser
  • Browser now connects to the server using that IP

🔁 Simple Flow 

User → Browser Cache → OS Cache → Resolver → Root → TLD → Authoritative → IP → Browser
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🧠 Real-Life Example

Think of DNS like asking for directions 🚗:

  1. You ask a local person (resolver)
  2. They guide you step by step
  3. Finally, you reach the exact location

⚡ Why DNS Resolution is Important?

  • Makes internet easy (no need to remember IPs)
  • Fast access using caching
  • Backbone of web browsing

🔐 Is DNS Secure?

Basic DNS is not encrypted ❌

But modern solutions like:

  • DNS over HTTPS (DoH)
  • DNS over TLS (DoT)

👉 Make it secure 🔒

✅ Conclusion

DNS resolution is the hidden process that:

  • Converts domain names into IP addresses
  • Helps your browser find websites
  • Works in milliseconds

Without DNS, we would have to remember IP addresses for every website 😅

Thanks for reading 😊

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