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 do not have to reconfigure the client PCs - Untangle works out of the box.

This tutorial shows how to install and use alterMIME. alterMIME is a tool that can automatically add a disclaimer to emails. In this article I will explain how to install it as a Postfix filter on Debian Etch.