Your Firewall Can't Hear Radio
Start with three ideas.
Every story in this book grows from one of these.
Your firewall guards the wires. Radio goes around it.
Cellular modems, badge readers and wireless links can reach your operation without ever passing through the firewall.
A connection nobody owns is a door nobody locks.
Every radio link needs an owner, a reason, and someone who notices when it changes.
Done means two checks pass.
The risky path is closed. And the device still does its job. The door still opens. The alarm still calls out.
Chapters 1 to 3 show how radio walks around the firewall. Chapters 4 and 5 show how to listen and decide. Chapters 6 and 7 show how to close a path without breaking the service, and where to start.