Course 1 · Free · Hands-on

How the Internet Works: a free hands-on course for beginners

Seven short lessons that take you from “I just click the link” to understanding what your computer, your router and the rest of the internet do in the second before a page appears. You won’t just read about it: every lesson has you watch it happen on your own connection.

7 lessonsAbout 15 minutes eachBeginnerFree

0 of 7 lessons done

By the end you’ll be able to

  • Follow every step between pressing Enter and seeing a page
  • Find your device’s private address and your public one, and explain why they differ
  • Open your router’s settings page and see what’s connected to it
  • Look up a website’s address yourself and time how fast it answers
  • Read an address like 192.168.1.0/24
  • Work out where a “connected, but no internet” problem really is

What you need: a computer with Windows, macOS or Linux and Chrome, Edge or Firefox. Some exercises also work on a phone. No experience at all.

Lessons
  1. 1

    The Journey of a Web Page

    The five things that happen after you press Enter, and how to watch each one, with timings, in your own browser.

    Open15 minutes · hands-on
  2. 2

    Find Your IP Addresses

    Find your device’s private address and your public one on Windows, Mac, Linux and your phone, and see why they never match.

    Open15 minutes · hands-on
  3. 3

    Meet Your Router

    Log into your router’s settings page, see every connected device, and check whether your provider shares your public address.

    Open15 minutes · hands-on
  4. 4

    Follow a Name to an Address

    Run DNS lookups yourself, compare the answers from different DNS servers, and learn to read record types and TTLs.

    Open20 minutes · hands-on
  5. 5

    Measure Your Connection

    Use ping and traceroute to time a round trip and see each network your data passes through on the way.

    Coming soonUntil then: Network Latency and Ping
  6. 6

    Read an Address Block

    Work out what 192.168.1.0/24 means and how many devices fit in it, then check your answers with the subnet calculator.

    Coming soonUntil then: What Is a Subnet?
  7. 7

    Put It Together: Connected, but No Internet

    A troubleshooting case that uses every lesson to find exactly where a broken connection fails.

    Coming soonUntil then: Fix “WiFi Connected But No Internet”

What do you know already?

Try these three now, then again when you finish the course. Pick one answer each and you’ll see why.

1. Your laptop’s Wi-Fi settings show 192.168.1.23, but a “what is my IP” site shows a completely different address. What’s going on?

2. You type examineip.com and press Enter. What does DNS do?

3. A ping test shows 20 ms. What does that number tell you?

Go deeper: IP Addresses Explained, our Kindle book on where addresses came from and how they work. · All courses

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