How the Internet Works, Part III - Reliability and Security

In Part II, we learned how an HTTP request travels across the Internet to the correct destination server, through several layers, and returns with a response. But how does this happen reliably and securely, without becoming corrupted or being intercepted by a malicious hacker?

How the Internet Works, Part II - Layers

What exactly happens when you enter a URL in your browser? How does your browser know what content to display? To answer this question, we need to understand how the various layers of the Internet work.