Open Source Unified Threat Management Software Options [closed]

Does anyone have experience or could recommend an open source Unified Threat Management (UTM) package that we could install on our network using hardware we already own? Looking for something that will filter viruses and malware at the perimeter of our network in addition to the normal firewall tasks.

I have found several solutions but before installing all of them to try them out, I wanted to see what the experts at ServerFault have experienced with regard to this. Is it unrealistic to look for an open source solution since there is significant work behind the scenes in keeping malware/virus databases up to date?

We have about 20 ip addresses to protect on our internal network, so we were looking at Open Source to keep costs down.

Here are some options the google came up with quickly:

  • http://www.endian.com/
  • http://www.astaro.com/
  • http://ostatic.com/openutm

I think untangle is a pretty big favorite. http://www.untangle.com/home