DSA Factory
All free lessons
Computer networks

Free Names and the web lessons

7 lessons, about 1½ hours in all. Each teaches one idea with a visual, then gives you a problem or a few questions on it. Read the lessons here, then create a free account to practise and keep your progress.

Start free with lesson 1See the full Names and the web path

Stage 0Names

  1. How DNS resolves a nameFollow a lookup from your laptop through a resolver, the root, a TLD server and an authoritative server.14 min
  2. DNS records and their time to liveLearn the record types you meet in practice, and the trade-off in choosing a TTL.12 min

Stage 1The web

  1. HTTP requests and responsesRead an HTTP message, choose the right method, and interpret the status code that comes back.13 min
  2. Cookies, and why HTTP versions differSee how a stateless protocol remembers you, and how HTTP/1.1, HTTP/2 and HTTP/3 each make loading a page faster.14 min

Stage 2Security and the whole journey

  1. TLS and HTTPSSee how a browser and server agree on a secret over an open network, and what a certificate proves.15 min
  2. Email: SMTP and IMAPFollow a message from sender to inbox, and see which protocol pushes mail and which fetches it.12 min
  3. What happens when you type a URLPut everything together: the whole journey from the address bar to a rendered page, and where the time goes.15 min

All of Names and the web is free

That’s the whole topic, from the first idea to the mastery stage, with no card needed. Create a free account to practise, keep your progress and carry on to the next topic.

Create your free account