Most topics in this book cover attack scenarios. Unfortunately, one day we might experience attempts against our own systems. This means our own security architecture will be tested, and we'll need to understand how to deploy, operate, and maintain defensive solutions that can help us protect, detect, block, scope, contain, and remediate threats as they come.
We want to be clear that the Raspberry Pi is not the ideal tool to leverage for cyber defense. Best practices all point to layering security solutions that offer various features such as application layer controls, stateful Firewall, intrusion prevention, access control, network segmentation, malware detection, network monitoring, data loss, and so on. Most tools that provide the level of protection we need to combat the threats seen on today's networks require very high power processing and tons of storage. Unfortunately, the Raspberry Pi does not offer this to us.
If we were looking to test some basic security...