Unit 7.3
IP Addresses and the Domain Name System (DNS)
Learning Objectives
By the end of this chapter, you will be able to:
- ✅ Define an IP address and its purpose.
- ✅ Differentiate between IPv4 and IPv6.
- ✅ Define the Domain Name System (DNS) and explain its function.
What is an IP Address? 📍
Internet Protocol (IP) Address: A unique numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
Think of it as a digital street address for your computer, phone, or any other connected device.
It ensures data packets are routed to the correct destination across the internet.
The Two Flavors of IP: IPv4 vs. IPv6
IPv4 (The Original)
Example: 192.168.1.1
- The first widely used version.
- 32-bit address space.
- Supports ~4.3 billion unique addresses.
- We've nearly run out! 📉
IPv6 (The Future)
Example: 2001:0db8:85a3::8a2e:0370:7334
- The new standard.
- 128-bit address space.
- Supports a virtually limitless number of addresses.
- Solves the address exhaustion problem. 📈
The Problem with Numbers
Computers are great at remembering numbers like:
142.250.190.78
Humans? Not so much.
Which is easier to remember?
142.250.190.78 or google.com?
Challenge: How do we bridge the gap between human-friendly names and computer-friendly numbers?
The Internet's Phonebook: DNS 📖
Domain Name System (DNS): A global, decentralized system that translates human-readable domain names (like www.google.com) into the numerical IP addresses that computers use to communicate.
Without DNS, we'd have to memorize IP addresses for every website we want to visit.
It's a critical, yet often invisible, service that makes the web user-friendly.
How DNS Works: A 4-Step Journey 🔍
- 1. Request: You type
www.google.com into your browser and hit Enter.
- 2. Query: Your computer sends a request to a DNS server, asking "What is the IP address for
www.google.com?"
- 3. Lookup & Respond: The DNS server looks up the domain in its database, finds the corresponding IP address (e.g.,
142.250.190.78), and sends it back to your computer.
- 4. Connect: Your browser now uses that IP address to connect directly to Google's web server.
⚡ This entire process happens in milliseconds! ⚡
Practical Application: DNS in Nepal 🇳🇵
When you visit a local Nepali website, the DNS process is essential for a fast connection.
Example: Visiting a local news site
- You type
www.ekantipur.com.
- Your Internet Service Provider (e.g., WorldLink, NTC) has its own DNS server. It quickly resolves this local domain name to an IP address, often for a server located within Nepal.
- This local resolution reduces latency, making Nepali websites load faster for users inside the country.
What if DNS Suddenly Stopped? 🤯
Discussion Question: What would happen to the internet if the global DNS system went offline?
- Human-friendly domain names (
google.com, facebook.com) would stop working.
- Email routing, which relies on domain names, would fail.
- The internet would still technically function, but you would need to know the exact IP address of every server you wanted to connect to.
- In short, the web as we know it would become almost unusable for most people.
Summary & Key Takeaways 🎯
- An IP address is a unique numerical label for a device on the internet, acting like a digital street address.
- DNS is the internet's phonebook, translating easy-to-remember domain names into the IP addresses computers need.
- IPv6 was created to solve the problem of running out of the ~4.3 billion available IPv4 addresses, ensuring the internet can continue to grow.
Thank You!
Any questions?
Next Topic: Unit 8.1 - Introduction to Web Development