Foundations

Linux Foundations

A complete visual Linux tutorial: build durable models of identity, storage, processes, networking, packages, shells, security, and diagnosis.

Containers, Illustrated

Follow one Linux process as a runtime gives it an isolated view, resource controls, filesystem layers, and a lifecycle.

Docker Multi-Architecture

Understand image indexes, platform manifests, emulation, native builders, and cross-platform container delivery.

intermediateExplore

The network

How computers find and reach each other

Networking, Illustrated

Follow one HTTPS request from hostname resolution to a server, and see which network layer makes each decision.

foundational · Reviewed Oct 2026Explore

Follow shop.example.com from your app to the root and back, see every cache its answer lands in, look up any record type on a map of the zone, then move the name to a new address and diagnose the ways a lookup fails.

SSH, Illustrated

Watch SSH establish server trust, build encrypted transport, authenticate a user, and open logical channels.

FoundationsOperational Reference

The web

What a browser and a server say to each other

HTTP Status Codes as a City Map

Five districts, one for each first digit, and a sign for every status code you are likely to meet. Choose a sign to see what the server is saying, who acts next, whether to ask again and which box probably wrote it.

foundational · Reviewed Oct 2026Explore

foundational · Reviewed Oct 2026Explore

CORS, One Request at a Time

Follow one request from a page on app.b.com to api.a.com and back. See when the browser sends a preflight, when the request reaches the server but the script still can't read the answer, and why the console's CORS error is often hiding a 500, a redirect or a CDN cache. Change the request or the server and watch the outcome move.