Chapter 1. Introduction

VoIPong is a sniffer utility which tries to detects Voice Over IP calls on a pipeline, and for those which have vocoder modules loaded, dumps actual conversation to seperate wave files. Currently it can catch calls made via a wide variety of protocols including SIP, H323, Cisco's Skinny Client Protocol. It can also catch calls made through dummy IP adapters which do not do any signalling but transport voice payload via RTP protocol.

It's been written in C language for performance reasons, proved to be running on Solaris, Linux and FreeBSD; though it's thought to compile and run on other platforms as well.

On a 45 Mbit/sec network traffic, it's been verified that VoIPong successfully detected all VoIP gateways and the VoIP calls. CPU utilization during the run has been found ranging between 66% - 80% on a 256MB RAM, Celeron 1700 Mhz Toshiba notebook.

With its powerful and extensible Dynamic Shared Object Modules (DSOM) subsystem, and its related API (will be documented later), new third party voice decoder modules can be coded and installed, resulting in a great flexibility. By default, VoIPong comes with two pre-written voice decoder modules for calls encoded with G711 (u-law) and G711 (a-law) . Audible output can be generated for calls encoded with any one of them.