Book Image

TrixBox Made Easy

By : Kerry Garrison, Barrie Dempster, Kerry Garrison (Project)
Book Image

TrixBox Made Easy

By: Kerry Garrison, Barrie Dempster, Kerry Garrison (Project)

Overview of this book

TrixBox is a telephone system based on the popular open source Asterisk PBX (Private Branch eXchange) Software. TrixBox allows an individual or organization to setup a telephone system with traditional telephone networks as well as Internet based telephony or VoIP (Voice over Internet Protocol). SugarCRM can be integrated with Asterisk, and is bundled with Trixbox offering real power and flexibility. The book begins by introducing telephony concepts before detailing how to plan a telephone system and moving on to the installation, configuration, and management of a feature packed PBX. This book is rich with practical examples and tools. It provides examples of well laid out telephone systems with accompanying spreadsheets to aid the reader in building stable telephony infrastructure.
Table of Contents (16 chapters)
TrixBox Made Easy
About the Authors
About the Reviewers
Free Chapter
Introduction to VoIP
TrixBox Configuration
Commonly Used VoIP Terms

Firewall Settings

If we are going to use any remote extensions or ITSPs, sooner or later we will need to deal with firewall issues. Unfortunately, the SIP protocol is not very friendly with firewalls and Network Address Translation (NAT).

SIP as a protocol design makes sense, if every computer on the Internet has a unique IP address. However, in many cases, the computers sit behind a firewall that performs NAT of some kind and is the only device with a publicly accessible IP address. This makes it quite difficult to manage sessions between machines as it requires a number of ports to be open to the machines involved in the connection. What this means is that we often have calling problems with NAT on our network, usually with a lack of audio or an inability to initiate calls.

To get around this, we will need to open some ports in our firewall to the TrixBox system. The following table lists the ports required for Asterisk to function efficiently: