Book Image

FreeSWITCH 1.2 - Second Edition

Book Image

FreeSWITCH 1.2 - Second Edition

Overview of this book

FreeSWITCH is an open source telephony platform designed to facilitate the creation of voice and chat-driven products, scaling from a soft-phone to a PBX and even up to an enterprise-class soft-switch. It is always exciting to design and build your own telephony system to suit your needs, but the task is time-consuming and involves a lot of technical skill."FreeSWITCH 1.2" comes to your rescue to help you set up a telephony system quickly and securely using FreeSWITCH. It is rich with practical examples and will give you all of the information and skills needed to implement your own PBX system.You will start with a detailed description of the FreeSWITCH system architecture. Thereafter you will receive step-by-step instructions on how to set up basic and advanced features for your telephony platform.The book begins by introducing the architecture and workings of FreeSWITCH before detailing how to plan a telephone system and then moves on to the installation, configuration, and management of a feature-packed PBX. You will learn about maintaining a user directory, XML dial plan, and advanced dial plan concepts, call routing, and the extremely powerful Event Socket. You will finally learn about the online community and history of FreeSWITCH."FreeSWITCH 1.2" is an indispensable tool for novice and expert alike.
Table of Contents (24 chapters)
FreeSWITCH 1.2
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Protecting SIP signalling


SIP signaling is important to encrypt. It contains both authentication information your phone utilizes to make and receive calls and it includes the Caller ID Name and Number of the caller and callee, by default in plain text. This is easy to sniff and to spoof. Encryption makes that harder. In addition, if you are using SRTP (Secure RTP), the SIP signaling contains the cryptography key used to keep your audio secure. Someone who observed this key in plain-text would easily be able to defeat the media encryption utilized.

Choosing between encryption options

There are a variety of encryption options available for FreeSWITCH. You can encrypt the signaling (that is, the SIP messages), the media (that is, the audio in the RTP stream), or both. Transport Layer Security (TLS) V1 encrypts everything over the TCP connection; this has the downside that jitter or delays due to TCP can occur. UDP is generally preferred for RTP and using TLSV1 has some additional traffic overhead...