Untangle Gateway Platform – The Open Source Network Gateway
http://www.untangle.com/

Untangle was founded with the vision of untangling the complexities of technology, initially targeting network security and control for SMBs. The company follows Open Source development practices to create better code and make it widely available. The Untangle Gateway Platform, the world’s first commercial-grade open source solution for blocking spam, spyware, viruses, adware and unwanted content on the network, provides a free and better alternative to costly, inflexible proprietary appliances. Untangle’s applications are currently being used in hundreds of businesses in a variety of industries, including financial services, real estate, education, bio-science, and professional services. This has been added to World Wide Web Reference Subject Tracer™ Information Blog.