Practical Computer Networking and Troubleshooting

When a network fails, can you identify the real cause, or do you find yourself changing settings and hoping something works?

A laptop connects to Wi-Fi but cannot reach a website. A server responds to a ping, yet its application remains unavailable. A new VLAN isolates the wrong devices, or a routing change leaves an entire office without access. These problems can look alike from the user's perspective, but each calls for a different investigation.

Without a clear understanding of how networks operate, troubleshooting becomes a frustrating cycle of trial and error. You may know individual commands but struggle to interpret their output, calculate subnets confidently, or distinguish a DNS failure from a routing or security problem.

Practical Computer Networking and Troubleshooting gives you a method for understanding the technology and investigating what actually went wrong.

Written by Gareth Varncombe, this practical guide brings together theory, worked calculations, guided laboratories, and fault scenarios. You'll learn not just which tools to use, but what each test can prove, what it cannot prove, and how to move from an observation to a defensible solution.

Inside, you'll learn how to:

• Understand the foundations: Follow data through network devices, Ethernet links, the OSI model, TCP/IP protocols, and end-to-end communication.
• Make sense of addressing: Work through IPv4 subnetting, address planning, IPv6, and neighbor discovery with explained calculations.
• Configure the path: Explore switching, VLANs, trunks, loop prevention, static routing, packet forwarding, and OSPF.
• Diagnose essential services: Investigate DHCP, DNS, NAT, and the dependencies behind everyday connectivity.
• Work with wireless and security: Examine wireless LAN behavior, segmentation, firewalls, and access-control decisions.
• Use evidence, not assumptions: Apply diagnostic commands, packet captures, monitoring data, and performance measurements to narrow the fault domain.
• Connect theory with practice: Tackle guided labs, practice problems, worked examples, and integrated cases involving WAN, VPN, cloud, and hybrid connections.

Built for readers who want usable skills, not just definitions.

The lessons develop progressively, so you can begin with the basics and build toward complex troubleshooting cases. No advanced mathematics is assumed. Where calculations matter, the steps and units are shown so you can understand the reasoning rather than memorize an answer.

You also don't need a costly rack of equipment to begin. Many exercises can be performed in a simulator or with virtual machines in an isolated lab. Commands and procedures are explained in context, with reminders to verify platform-specific details and work only on systems you are authorized to test.

The recurring approach is simple: define the expected behavior, collect evidence, make a controlled change, and verify the result.

Whether you're studying networking, preparing for a technical role, supporting users, or strengthening your skills as an IT practitioner, this book is designed to help you ask better questions, interpret results more accurately, and document your work effectively.

Turn networking problems into problems you can investigate systematically.

Get your copy of Practical Computer Networking and Troubleshooting and start building the knowledge and practical judgment to understand connections, find faults, and verify your fixes.