Learning Objectives

By the end of this chapter, you should be able to:

• Inspect network interfaces.
• View and configure IP addresses.
• Verify connectivity.
• Diagnose DNS problems.
• Identify listening ports.
• Inspect active network connections.
• Monitor running processes related to networking.
• Troubleshoot common Linux networking issues using command-line tools.

Introduction

A DevOps engineer spends a significant amount of time troubleshooting systems rather than building them.

When a production server becomes unreachable, a website stops responding, or a Kubernetes node fails to join a cluster, one of the first places engineers turn is the Linux terminal.

Knowing networking theory is valuable, but being able to verify that theory on a live Linux system is what distinguishes an engineer who understands networking from one who has only memorized concepts.

This chapter focuses on the Linux commands introduced in your TechWorld with Nana Networking module and expands on them with practical explanations, examples, and troubleshooting scenarios.

How Professional DevOps Engineers Troubleshoot

When a server cannot communicate with another server, experienced engineers rarely guess.