Lesson 04 — IPv4 & IPv6 Addressing

Lesson Overview

Imagine trying to send a letter without knowing the recipient’s address.

The postal service would have no idea where to deliver it.

Computer networks work in exactly the same way.

Every device connected to a network requires a unique address so that information can be sent to the correct destination.

This unique address is called an Internet Protocol (IP) Address.

Whether you’re deploying AWS EC2 instances, configuring Kubernetes clusters, securing enterprise networks, or troubleshooting cloud applications, understanding IP addressing is one of the most important networking skills.

In this lesson, you’ll learn how IPv4 and IPv6 work and why IP addressing forms the foundation of modern networking.

Learning Objectives

After completing this lesson, you will be able to:

Explain what an IP address is.
Understand the purpose of IPv4 and IPv6.
Differentiate between public and private IP addresses.
Understand subnet masks and CIDR notation.
Explain basic subnetting concepts.
Understand how IP addressing supports enterprise and cloud networking.

What is an IP Address?

An IP Address is a unique logical address assigned to every device connected to a network.

It allows devices to:

Identify one another.
Send data.
Receive data.
Communicate across local networks.
Access the Internet.

Without IP addresses, computers would not know where to send information.

Think of an IP address as the postal address of a computer.

Why IP Addresses Matter

Every connected device requires an IP address.

Examples include:

Laptops
Mobile Phones
Servers
Printers
Firewalls
Routers
Cloud Virtual Machines
Kubernetes Nodes
IoT Devices

Whenever two devices communicate, they exchange information using IP addresses.

IPv4 Addressing

IPv4 (Internet Protocol Version 4) is the most widely used addressing system today.

An IPv4 address consists of 32 bits divided into four sections called octets.

Example:

192.168.1.10

Each octet ranges from 0 to 255.

Examples:

10.0.0.5

172.16.100.25

192.168.1.100

IPv4 Structure

192 . 168 . 1 . 10

|     |     |    |
Octet Octet Octet Octet

Each octet contains 8 bits.

Total:

8 + 8 + 8 + 8 = 32 Bits

Why IPv6 Was Created

When IPv4 was designed, the Internet had very few connected devices.

Today we have:

Smartphones
Laptops
Tablets
Smart TVs
Cloud Servers
IoT Devices
Autonomous Vehicles
Industrial Equipment

IPv4 provides approximately:

4.3 Billion Addresses

That seemed enormous decades ago.

Today it is no longer enough.

IPv6 was created to solve this problem.

IPv6 Addressing

IPv6 uses 128-bit addresses, providing an almost unlimited number of unique IP addresses.

Example:

2001:0db8:85a3:0000:0000:8a2e:0370:7334

IPv6 addresses are written in hexadecimal and separated by colons.

Advantages include:

Vast address space
Improved efficiency
Better scalability
Simpler routing
Built-in support for modern networking

As cloud adoption continues to grow, IPv6 usage is steadily increasing.

IPv4 vs IPv6

IPv4	IPv6
32-bit Address	128-bit Address
Four Decimal Octets	Eight Hexadecimal Groups
~4.3 Billion Addresses	340 Undecillion Addresses
Widely Used Today	Increasing Adoption
NAT Commonly Used	NAT Often Not Required

Both protocols are important for modern IT professionals.

Public vs Private IP Addresses

IP addresses are divided into two categories.

Public IP Addresses

Public IP addresses are reachable from the Internet.

Examples include:

Company websites
Cloud servers
Public APIs
Email servers

Public IP addresses are assigned by Internet Service Providers (ISPs) or cloud providers.

Private IP Addresses

Private IP addresses are used inside internal networks.

They cannot be accessed directly from the Internet.

Common private address ranges include:

Range	CIDR
10.0.0.0 – 10.255.255.255	10.0.0.0/8
172.16.0.0 – 172.31.255.255	172.16.0.0/12
192.168.0.0 – 192.168.255.255	192.168.0.0/16

These ranges are widely used in:

Homes
Offices
Enterprise Networks
Cloud Virtual Private Clouds (VPCs)

Static vs Dynamic IP Addresses

Static IP Address

A static IP address never changes.

Common uses:

Web Servers
Database Servers
Firewalls
DNS Servers

Dynamic IP Address

A dynamic IP address is automatically assigned by a DHCP server.

Common uses:

Employee laptops
Mobile devices
Guest Wi-Fi
Home networks

Most end-user devices receive dynamic addresses.

Subnet Mask

A subnet mask identifies which part of an IP address represents the network and which part represents the host.

Example:

IP Address

192.168.1.100

Subnet Mask

255.255.255.0

This tells the device which computers belong to the same local network.

Subnet masks are essential for routing traffic correctly.

CIDR Notation

Modern networks use CIDR (Classless Inter-Domain Routing) notation.

Instead of writing:

255.255.255.0

We write:

/24

Examples:

CIDR	Subnet Mask
/8	255.0.0.0
/16	255.255.0.0
/24	255.255.255.0
/32	Single Host

CIDR notation is used throughout cloud platforms such as AWS, Azure, and Google Cloud.

Basic Subnetting

Subnetting divides a large network into smaller networks.

Instead of one large network:

192.168.1.0/24

An organization might create:

Finance

192.168.1.0/26

HR

192.168.1.64/26

IT

192.168.1.128/26

Servers

192.168.1.192/26

Benefits include:

Better performance
Improved security
Easier management
Reduced broadcast traffic

Subnetting is a core skill for Cloud Engineers and Network Engineers.

IP Address Assignment

When a device connects to a network, it typically follows this process:

Device Starts

↓

DHCP Request

↓

IP Address Assigned

↓

Default Gateway Assigned

↓

DNS Server Assigned

↓

Network Communication Begins

You’ll learn about DHCP in a later lesson.

IP Addressing in Cloud Computing

Every cloud platform relies on IP addressing.

Examples include:

AWS EC2 Instances
Azure Virtual Machines
Google Compute Engine
Kubernetes Pods
Load Balancers
Virtual Private Clouds (VPCs)

As a Cloud Engineer, you’ll configure IP addresses regularly.

IP Addressing in Cybersecurity

Security professionals use IP addresses to:

Investigate incidents.
Identify attackers.
Review firewall logs.
Analyze network traffic.
Detect suspicious activity.
Configure security controls.

Understanding IP addressing is fundamental to network security.

Common IP Commands

Throughout your IT career, you’ll frequently use commands to view and troubleshoot IP configurations.

Windows

ipconfig

ipconfig /all

Linux

ip addr

hostname -I

ip route

These commands help verify network configuration and diagnose connectivity issues.

Real-World Example

Imagine an employee opens:

https://www.gohackerscloud.com

Behind the scenes:

Laptop

192.168.1.25

↓

Router

↓

Public IP

↓

Internet

↓

Cloud Load Balancer

↓

Web Server

↓

Response Returned

Every device along the path uses IP addresses to ensure the request reaches the correct destination.

Best Practices

As an IT professional:

Understand IPv4 and IPv6.
Learn private IP address ranges.
Use CIDR notation confidently.
Plan IP address allocation carefully.
Avoid overlapping networks.
Document IP addressing schemes.
Use static IPs only when required.
Monitor IP utilization in enterprise environments.

A well-designed IP addressing plan improves scalability, security, and troubleshooting.

Key Takeaways

After completing this lesson, you should understand:

What an IP address is.
The differences between IPv4 and IPv6.
Public and private IP addressing.
Static and dynamic IP addresses.
Subnet masks and CIDR notation.
Basic subnetting concepts.
Why IP addressing is essential in Cloud Computing and Cybersecurity.

Summary

IP addressing is the foundation of all network communication.

Every website, cloud service, enterprise application, and mobile device depends on IP addresses to send and receive information accurately.

As you progress through GoHackersCloud Academy, you’ll configure IP addressing in AWS VPCs, Azure VNets, Kubernetes clusters, VPNs, firewalls, and enterprise networks.

Mastering these fundamentals will make advanced networking, cloud architecture, and cybersecurity concepts much easier to understand.

Next Lesson

➡️ Lesson 05 — Routing & Switching

In the next lesson, you’ll learn how routers and switches forward traffic across networks, discover how routing decisions are made, and understand the technologies that enable communication across enterprise networks and the Internet.