As a network administrator, content filtering is one of the most difficult challenges I face. Whether you’re keeping your employees off time-consuming social networks, or protecting your family from the dangers of the web you need a strong solution to combat the threats the open internet contains. It’s a fact; there are over 35,000 websites categorized as adult being tracked by Alexa right now. Between banner ads, pop-ups, and redirects there is no telling what your kids might accidentally (or intentionally) come across when surfing the internet. I have spent a great deal of time searching for the most effective solution and my results may surprise you.
I have tried installing software on every computer, it quickly becomes too much of a hassle to maintain. And I have tried some of the out of the box solutions, but when looking at the shockingly high price tag, I quickly found an open source alternative. Open Source software is rapidly coming to the forefront in mainstream networking. ClearOS is an easy to install live-cd software, and it’s remarkably scalable.
For starters, you are going to need an old computer. AMD or Intel will do, the beefier the specifications the more you can do with this all in one box.
Once you have the system you can download the ISO directly from the web site here, and use your favorite windows based software to burn the ISO into a usable disk. The resulting disk will wipe the contents of the hard drive and walk you through the easy installation. There is even a video on the website here to walk you through it.
Once you have it installed, ClearOS you will want you to take some time to configure it. You will see that you can either do this directly on the computer or you can access it from you internet browser on another computer. Under the gateway tab, you will see Protocol Control and Content Filter; these are the two most important features and the reason I love ClearOS.
Starting with content Filter, there is a huge continuously updated database of blacklisted websites all categorized for your convenience you can get as strict as you please, blanket blocking everything, or simply specific categories. You can even set up Specific internet access times. The real Gem is protocol control though; this allows you to block specific types of traffic. This is particularly useful in blocking specific chat programs, games, and peer 2 peer networks.
Once you have the system configured to your liking, you will want to install it in between your modem and router. You can go into the router configuration and disable DHCP so that the ClearOS box is now the control device on your network. After everything is up and running you should take the opportunity to look at some of the other features this FREE software has.
I am particularly excited about some of the features under development
The way the content Filter works is that when the local computer requests a web page, ClearOS references the name of the site against the blacklist and if it gets a match, it denies the request. The second level of defense is the Protocol Control; it helps prevent some of the applications that subvert this DNS look-up method. Depending on how much you trust the users on your network, you can even go so far as to block specific download extensions such as executable programs to prevent them from installing proxy software, or the like. In four years there is one thing I can assure you, nothing short of removing the internet connection is fool proof. Given enough time and determination, firewall subversion is inevitable. The only thing you can do is make it as difficult as possible. On the bright side if your child gets particularly good at usurping your network, they will have a good head start on a network security career!