HowtoMatrix

Untangle
bundles common open-source applications for blocking spam, spyware,
viruses, adware and unwanted content on the network in one single Linux
distribution. It can be integrated into existing networks either as a
router or as a transparent bridge (directly behind the router, but
before the switch that connects the client PCs with the router). The
best thing about Untangle is that you don’t have to reconfigure the
client PCs - Untangle works out of the box.

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