Chapter 21. Troubleshooting Defense Components

Bad things happen. It doesn't matter how much time and effort your team has spent researching, designing, implementing, and maintaining your network security architecture; something is going to break. That's why having a strong troubleshooting methodology is important to your success as a network security practitioner.

Troubleshooting is simply a diagnostic process that is applied to a problem to fix it. "Symptoms" are gathered to determine the cause and solution for network security problems. These symptoms usually start out at a very general level ("Why can't I connect to a server?") and progress to more specific symptoms ("Why can I connect to other servers and not this one?") until the root cause of the problem is discovered and fixed.

Instead of trying to cover a selection of network security products and hoping they apply to your environment, in this chapter we focus on general troubleshooting techniques in the context of sample problems. Much of this chapter is spent applying a set of basic tools to gather the necessary input for your troubleshooting progression. We apply a hands-on approach to help you develop a methodology and toolkit that will work effectively in any environment.