How the public network works from the wire up — addressing, routing, and the protocols every service depends on. It spans from the beginner’s mental model of what happens when you open a browser, to the frontend’s view of delivery and caching, to the backend’s view of sockets, proxies, and TLS.
The Internet is the largest engineered system humans have ever built. It connects billions of devices across every continent, moves an unfathomable volume of data every second, and does so without a central controller, a master switch, or a single point of failure. When you type a web address into your browser and press Enter,…
Every device on a network needs an identity. But not just one identity—it needs two, and they serve completely different purposes. A MAC address is a permanent, hardware-burned identifier that tells you which physical device is on the local network. An IP address is a software-assigned, changeable identifier that tells the network where that device…
Every time you type an address into your browser, you are using a domain name. It is the human-friendly label that stands in for a string of numbers no one wants to memorize. But a domain name is not a website, not an email address, and not a server. It is a name—a unique identifier…
Every link you click, every address you type, every API endpoint you call is a URL. It looks simple enough—a string of characters that takes you somewhere. But that string is a precisely structured address with distinct components, each with a defined role. Understanding the anatomy of a URL is the difference between treating it…
When you type a website address into your browser and press Enter, something has to answer. The domain name you typed has been translated into an IP address, and that IP address points to a computer somewhere in the world that holds the files making up the website. That computer is a server, and the…