Introduction to Networking
The invisible layer that connects every server, container and cloud service you will ever manage.
Every deployment you will ever do — a website, an API, a Kubernetes cluster — is really just computers talking to each other over a network. When something breaks in production, the problem is very often networking, not the code. That’s why it’s a core DevOps skill.
🎯 Learning Objectives
By the end of this lesson you will:
- Understand what a computer network is
- Know why networking matters for DevOps
- Understand the client–server model
- Get a plain-English view of the TCP/IP model
What is a Network?
A network is two or more devices connected so they can share data. Your laptop talking to a website, a container talking to a database, a server calling a payment API — all of it is networking.
The biggest network of all is the internet: millions of networks joined together.
💡 The one-line version
A network is just devices that can send messages to each other. DevOps is largely about making sure the right messages reach the right place — quickly, reliably, and securely.
The Client–Server Model
Almost all network communication follows one simple pattern:
| Role | What it does | Example |
|---|---|---|
| Client | Asks for something (sends a request) | Your browser, a mobile app, curl |
| Server | Answers the request (sends a response) | A web server, an API, a database |
Client ────── request ──────▶ Server
◀────── response ──────You open example.com, your browser (client) sends a request, the web server responds with the page. That request/response round trip is the heartbeat of the web.
How Data Travels — The TCP/IP Model
Data doesn’t jump from client to server in one piece. It moves through layers, each with one job. The practical model used on the internet is TCP/IP, with four layers:
| Layer | Job | You’ll meet |
|---|---|---|
| Application | The actual data/app protocol | HTTP, DNS, SSH |
| Transport | Reliable delivery between programs | TCP, UDP, ports |
| Internet | Finding the right machine | IP addresses, routing |
| Link | The physical/local network | Ethernet, Wi-Fi, MAC |
💡 Why layers help
Each layer only worries about its own job. HTTP doesn’t care how the bytes travel; it trusts the layer below. This is exactly how DevOps tooling is built — small pieces with clear responsibilities.
See It Yourself
Every networked machine has an address. Let’s look at yours and reach a public server:
ip addr # your machine's network addresses (Linux)
ping -c 3 google.com # can I reach that server?ping sends a tiny message and measures how long the round trip takes. If it works, you have a working network path to that server.
🧪 Hands-on Lab
Explore Your Network
- Find your machine’s IP address
- Ping a public website and note the response time
- Ping a website that doesn’t exist and observe the difference
🧠 Knowledge Check
In the client–server model, what does the client do?
Which TCP/IP layer is responsible for IP addresses and finding the right machine?
💼 Interview Preparation
Why is networking knowledge important for a DevOps engineer?
Summary
You now know what a network is, how the client–server model works, and how data travels through the layers of the TCP/IP model. Next, we’ll zoom into the addresses and ports that make delivery possible.