HylaFax is a robust and reliable software package designed to send and receive facsimiles and alpha-numeric pages. HylaFax is designed around client-server architecture.

Vyatta is an opensource router platform based on linux kernel and the leader in open networking and network virtualixation.

PHP-IDS is an open-source IDS made for and in PHP. It is a collection of blacklist filters designed to detect common (and less common) intrusions that can occur in PHP applications, such as SQL injections.

Open source and online code collaboration has really create so many great libraries on the net, some of the most useful for any web designer is the variety of JavaScript libraries.

An IDS is a specialized program that knows how to parse and interpret network traffic and send alarms to interest party based on configured signatures or rules –similar to a burglar alarm. Snort is an opensource IDS.

Blender 3D is an amazing open source 3D graphic modeling application. Blender is a very powerful 3D graphic modeling application comparable to other expensive high-end 3D software such as 3DS Max and Maya.