In Module 2 we watched a frame get handed off from one device to another on a single segment of wire. That’s a useful trick if everything you care about lives in the same room. It is not how the internet works.

The third module in the Cleartext series. Moves past the single-segment view of Module 2 and walks Layer 3: how IP addresses identify hosts across a network nobody owns, how routing decisions get made, what ICMP actually does, and the security weaknesses baked into each. The module that explains why “the internet” works at all.

In Module 1 we walked the path of a packet from a laptop on a coffee shop wifi to a server somewhere on the internet. We treated Layer 2 as a thin wrapper that gets your packet across one hop. That was a useful simplification. It was also a lie of omission.

The second module in the Cleartext series. Pulls back the Layer 2 simplification from Module 1 and walks through frames, MAC addresses, and switches, then maps the local-network attacks that live there: ARP spoofing, MAC flooding, and VLAN hopping. The why-the-attacker-next-to-you-already-owns-the-network module.

You type curl https://example.com and hit enter. 200 milliseconds later, the server’s response is on your screen. In that 200 milliseconds, a lot happened.

The first module in the Cleartext series. Walks through the path a packet takes from your terminal to a remote server and back, then maps the categories of attack that live at each layer. Designed as the foundation that later modules build on.