SmoothWall Corporate Server is an extremely effective way of turning a PC into a dedicated hardware firewall sitting on its own hardened operating system. The company has now released a bolt-on to the Corporate Server to provide even more protection - Smooth Guardian, a multi-layered content filtering package.
Hardware requirements are refreshingly underpowered, and you could probably use that old PC that's knocking around the office. After a fittingly smooth installation, helped by an excellent set of PDF manuals, setting up user lists and customizing the database and word lists are very, very simple.
SmoothGuardian provides organizations with three lines of defense against hostile internet traffic. The first is a blacklist of URLs, domains and IP addresses. Assuming this doesn't pick up a suspect web site, SmoothGuardian performs both a MIME and a PICS (platform for internet content selection) check on the web site to see if there is any harmful content being downloaded. If this isn't enough to prevent the web page being downloaded, the final check is a full keyword content check. This not only looks for words but also for phrases. SmoothGuardian uses a threshold method to gauge the suitability of the page, When a certain number of words or instances of words is reached, the page is then blocked. Furthermore, phrases used in a permissible context (such as on medical web sites) reduce the word count.
There are two further features which add even more protection. Administrators can set up 'allow' lists which override the URL's presence on a black list; they can also be extremely draconian and specify which URLs can be visited - no site not on the list will be allowed.
Because these operations are performed in series rather than parallel, processing overheads are considerably lower than with some products that do all three of these at once.
Perhaps the only drawback for companies considering installing SmoothGuardian is that they will also have to install the Corporate Server, which may dissuade companies which already have firewalls in place (which, one hopes, is all of them). However, given the rave reviews that Corporate Server has received, and the quality and functionality of SmoothGuardian, it may be a very wise investment.