At times, troubleshooting can be a simple process. At some point, perhaps even when working through the examples in this book, you made a change to pfSense’s configuration (or perhaps somewhere else on your network), and your network was no longer functioning normally. In such cases, resolving the problem can be as simple as remembering what change you made that caused the malfunction and undoing that change. A good proportion of network problems can be solved in this way.

However, in other cases, troubleshooting is not that easy. The cause may be something outside our control, or even if the cause was something we did, we may not be able to isolate it down to a single cause. The network on which the problem has manifested itself might be a critical resource for a company, and we cannot just troubleshoot it at any time—we might have to...