The Internet, from Scratch

Taught by Pip

Welcome aboard

Ahoy — Pip here, your lighthouse keeper. The internet can feel like one big magic cloud, but it isn't magic at all. It's wires, signals, and a few simple agreements that computers keep with each other, over and over, at the speed of light.

In this course we'll follow a single click on its whole journey: out of your device, down a cable, across the world, and back again with a web page in tow. We'll take it one short stop at a time — a plain idea, an everyday picture to make it stick, then onward.

You won't leave knowing everything. You will leave able to point at any part of the internet and say, plainly, what it does and why. That's a real map of the harbor. Let's cast off. 🔦

1. What the Internet Actually Is Free previewThe internet isn't a cloud. It's real cables and computers agreeing to pass your messages along. Here's the honest big picture.
2. Bits and Signals: How a Wire Carries a Message 🔒How your messages become on-and-off pulses, and how electricity and light carry those 1s and 0s down a wire.
3. Packets: The Postcards of the Net 🔒How big messages travel as small labeled chunks called packets, and why splitting them up makes the internet faster and tougher.
4. IP Addresses: Everything Has a Number 🔒Plain-English guide to IP addresses — the numbers that give every device on the internet a place packets can reach.
5. DNS: The Internet's Phone Book 🔒How DNS quietly turns a friendly name like portmint.com into the number a computer needs, on every single click.
6. Routers and the Journey of a Packet 🔒How a packet hops from router to router across the world — the relay race that carries your message from here to there.
7. Protocols: The Rules Everyone Agrees On 🔒How shared rulebooks called protocols let computers cooperate, and how TCP makes your messages arrive whole and in the right order.
8. Clients, Servers, and the Request 🔒How your device asks and a server answers — the simple back-and-forth conversation that sits behind every web page you load.
9. HTTP and the Web Page in Your Browser 🔒How HTTP lets your browser ask for a web page and a server send it back, watched step by step as the page builds.
10. HTTPS: Locks, Keys, and Staying Safe 🔒How the little padlock works — scrambling your messages and proving the other side is really who it claims to be.
11. The Whole Journey of One Click 🔒Trace one web click from tap to page, stitching together DNS, packets, routers, HTTP, and HTTPS into a single end-to-end voyage.