Practical VoIP Security
Written for the thousands of IT professionals who are now responsible for deploying and maintaining secure VoIP networks, this book covers evaluation, design, integration, and management of VoIP networking components.
TABLE OF CONTENTS Practical VoIP Security
Chapter 8: Support Protocols
Introduction
Protocols such as MGCP and SIP, or protocol umbrella groups like H.323, are usually the first things that come to mind when discussing VoIP technology. Although they are all great protocols in their own right, they depend on, and interoperate heavily with, support protocols. Many of the support protocols that are used by VoIP architectures enable services and features required for proper network operation.
This chapter will cover several of the support protocols typically found in VoIP environments and some of the security implications that they bring with them. This chapter is not intended to be an all-inclusive tutorial on these protocols. Instead, the intent is to review both their use and any security implications involving your network.
| Note | It is important to keep in mind that most of these support protocols do not include any encryption or authentication mechanisms by default. For this reason, most of this traffic is susceptible to interception and/or modification. Proper network planning and configuration is thus essential. |
DNS
The Domain Name System (DNS) is a static hierarchical name resolution architecture that relies on client/server communication for operation. DNS is a protocol that many use every day and may not know it. Whenever someone browses the Internet, DNS is used in the background to translate host names into IP addresses so that the proper network destinations can be found. DNS is equally important in VoIP networks for its ability to resolve destination endpoint addresses or allow gateway registration to call servers and gatekeepers by...
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