This chapter is only a brief guide to the most common VoIP security technologies prevalent today. There are a plethora of additional resources including sites such as www.hackingvoip.com, books on Hacking VoIP, and on Computer Security.
Taking the basic steps outlined in this chapter will provide you sufficient amount of security against today's most common hacks, DoS attacks, and abuses. This should allow most small to medium sized PBXes or hosted VoIP systems to operate securely and reliably.
We now move on to the last chapter in this book where we see how to react when things go wrong, we're not able to implement something, or we hit a bug in FreeSWITCH. We'll learn the basics about troubleshooting, asking for help, and reporting problems.