Once you sign up, you’ll see a set of thirteen lessons. The first part (Basics) walks you through the simulator and covers core concepts like packets, headers, routing, and more. The second part covers the fundamentals of spoofing; the third, across three lessons, explains how a denial-of-service (DoS) attack works; and the fourth bundles topics like bypassing resource blocks, man-in-the-middle (MitM) attacks, and how traceroute works.
In each lesson, you’ll track how packets move between network nodes, craft your own packets by setting their headers, and use them to attempt a successful attack.
The project’s author says they use Netsim as a student exercise and plan to create similar interactive textbooks to illustrate how the network stack and a CPU work, as well as for robot programming. The Netsim code is written in PHP and available on GitHub.