Untangle is a ubuntu-based network software suite. It combines many powerful open-source technologies to provide for a great and inexpensive network gateway server. More at http://untangle.com
This is Untangle 9.21 for x32 architecture. This is the .iso file used for CD installation. Check untangle's website for details.
This source is not provided as an offical Untangle release, just an alternative source because their download server is not as quick as it should be.