Subnetting

Learn how to divide networks efficiently and calculate subnets like a professional network engineer.

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About This Course

Subnetting is the process of dividing a large network into smaller and more manageable subnetworks. In this lesson you will learn:

Subnetting is one of the most important networking skills required by Network Administrators, Engineers and Cyber Security Professionals.

Course Notes

Subnetting Note 1

Introduction to Subnetting

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Subnetting Note 2

Subnet Masks and Networks

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Subnetting Answers

Exercises Solutions

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Video Lessons

Watch all lessons for this topic step by step.

Subnetting Introduction

Lesson 1: Introduction to Subnetting

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Subnet Masks

Lesson 2: Subnet Masks

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CIDR

Lesson 3: CIDR Notation

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Topics Covered

Subnet Mask

Understand how subnet masks separate network and host portions.

CIDR Notation

Learn CIDR notation such as /24, /25, /26 and more.

Network Address

Identify network addresses correctly.

Broadcast Address

Understand how broadcasting works within a subnet.

Usable Hosts

Calculate usable host addresses.

Subnet Design

Design practical networks for companies.

Examples

Example 1

IP Address: 192.168.1.0/24

Subnet Mask: 255.255.255.0

Usable Hosts: 254

Example 2

IP Address: 192.168.1.0/25

Subnet Mask: 255.255.255.128

Usable Hosts: 126

Exercises

  1. Convert /24 into subnet mask.
  2. Convert /25 into subnet mask.
  3. How many usable hosts are available in a /24 network?
  4. How many usable hosts are available in a /26 network?
  5. Find the network address of 192.168.1.50/24.
  6. Find the broadcast address of 192.168.1.50/24.
  7. Explain the purpose of subnetting.
  8. Differentiate Network Address and Broadcast Address.

Exercise Answers

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