In this chapter, we provided four security designs for you to review. The first three were chosen to highlight the requirement to match the needs of the business with the design of the perimeter security. In each case, we started with a description of the business needs for the network and moved from there to a design to meet those needs.
We followed these case studies with an example pulled from the practical assignment of a GCFW honors student. This example was substantially more complicated than the previous case studies and provided an interesting assortment of security techniques. Studying other professional's designs is one of the best ways to discover new ways to protect the networks you are responsible for.
Now that you have learned how to design secure networks, it's time to learn how to administer, test, and improve them. The next and final part of this book is on perimeter assessment. In it, you will learn how to maintain your security perimeter, monitor it for unusual activity, troubleshoot it when problems crop up, and test it to make sure it is functioning. Chapter 23, "Design Under Fire," builds on the principles of creating and maintaining a security perimeter by presenting a lesson on improving the security of the network through adversarial review. This chapter uses two more GCFW practicals to demonstrate how even good security designs can be improved by looking at them through the eyes of an attacker.