Chapter 1 – Introduction to Web & Internet Basics

The Internet - Global Network Connecting the World

Table of Contents

What is the Internet?

The Internet is a global network connecting millions of computers for communication and data sharing. It allows devices worldwide to connect and exchange information.

How is data transferred?

Data transfer on the internet occurs through packets. When you send data (like an email or load a webpage), it's broken into small packets that travel through various network devices to reach their destination. These packets are then reassembled at the receiving end.

The process involves:

How to access a website

To access a website, you need to:

  1. Enter URL: Type the website address (like www.example.com) in your browser
  2. DNS Resolution: Your computer contacts DNS servers to convert the domain name to an IP address
  3. Connection: Browser establishes a connection with the web server using the IP address
  4. Request: Browser sends an HTTP/HTTPS request for the webpage
  5. Response: Server sends back the HTML, CSS, JavaScript, and other files
  6. Rendering: Browser interprets and displays the webpage

Who assigns the IP Address?

IP addresses are assigned by:

In-depth Working of DNS

DNS works through a hierarchical system:

  1. Root Servers: 13 root servers worldwide that know about top-level domains
  2. TLD Servers: Handle specific top-level domains (.com, .org, .net, etc.)
  3. Authoritative Servers: Contain the actual DNS records for domains
  4. Recursive Resolvers: Your ISP's DNS servers that do the actual lookups

When you type a domain name:

Problems in Data Transfer and MAC Address

Common data transfer problems include:

MAC Address: Media Access Control address is a unique identifier assigned to network interfaces. It's a 48-bit (6-byte) address typically expressed in hexadecimal format.

MAC addresses are used for:

What is Port Numbers

Port numbers are 16-bit numbers (0-65535) that identify specific applications or services running on a device. They allow multiple applications to use network services simultaneously.

Common Port Numbers:

IPv4 & IPv6

IPv4: Internet Protocol version 4 uses 32-bit addresses (4 bytes) in dotted decimal format (e.g., 192.168.1.1). It provides about 4.3 billion unique addresses.

IPv6: Internet Protocol version 6 uses 128-bit addresses (16 bytes) in hexadecimal format (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). It provides approximately 340 undecillion unique addresses.

Key Differences:

MAC Address Format

MAC addresses are 48 bits (6 bytes) long and are typically represented in hexadecimal format with colons or hyphens separating each byte.

Format Examples:

MAC Address Structure:

Port Number Format

Port numbers are 16-bit unsigned integers ranging from 0 to 65535.

Port Number Ranges:

Port Number Examples:

Port Protocol Service
80 TCP HTTP
443 TCP HTTPS
53 UDP/TCP DNS

Local Area Network, Switch & Router

Local Area Network (LAN): A network that connects computers and devices in a limited geographical area like a home, school, or office building.

Network Switch: A device that connects multiple devices on a computer network. It uses MAC addresses to forward data to the correct destination within the LAN.

Router: A device that connects multiple networks together. It routes data packets between different networks using IP addresses.

Key Differences:

Public and Private Addresses

Public IP Addresses: Globally unique IP addresses assigned by ISPs that can be accessed from anywhere on the internet.

Private IP Addresses: IP addresses used within private networks that are not routable on the public internet.

Private IP Address Ranges:

Network Address Translation (NAT) allows multiple devices on a private network to share a single public IP address.

Modern Routers

Modern routers combine multiple functions:

Modern routers often include parental controls, Quality of Service (QoS), and guest network features.

What is a VPN?

VPN (Virtual Private Network): A technology that creates a secure, encrypted connection over a less secure network, such as the internet.

How VPN Works:

  1. User connects to VPN server
  2. Authentication occurs
  3. Encrypted tunnel is established
  4. All internet traffic is routed through the VPN
  5. Data appears to come from the VPN server's IP address

VPN Benefits:

What is Web Development?

Web development is the process of creating websites and web applications that run on the internet. It involves:

Web Development Technologies:

Basic HTML Structure Example

<!DOCTYPE html>
<html>
<head>
  <title>My First Webpage</title>
</head>
<body>
  <h1>Hello, World!</h1>
  <p>This is my first webpage.</p>
</body>
</html>

What is the MERN Stack?

MERN Stack: A popular full-stack JavaScript framework for building web applications.

MERN Components:

MERN Stack Advantages:

Who is a Full-Stack Developer?

Full-Stack Developer: A developer who works on both the frontend and backend of web applications.

Responsibilities:

Skills Required:

Key Concepts Summary

Topic Description
Internet A global network connecting millions of computers for communication and data sharing.
Web Basics Interconnected documents and resources accessible via the Internet.
IP Address A unique number assigned to each device on the network.
DNS Domain Name System translates domain names to IP addresses.
Web Browsers Applications that read HTML and display web pages.

Chapter 1 Summary

Key Takeaways

What You Learned

In this chapter, you explored the foundational concepts of the World Wide Web:

Next Steps

Now that you understand the web's infrastructure, you're ready to learn HTML - the language used to create web content. In Chapter 2, you'll discover:

Practice What You've Learned

Ready for the next chapter? Continue to Chapter 2 →

Reference Video for Chapter 1