Commercial filters are often expensive, especially when used on a large number of computers, as would be the case in a school computer lab or in small or medium companies with computer networks. In contrast, open source filters are generally freely available for download. In addition, since commercial filters are proprietary, in many cases the system administrator does not have the opportunity to modify or even view the lists of blocked sites.
With a typical server-based filtering and virus scan solution running on a proprietary operating system, you would have to pay hundreds or possibly thousands of dollars for the server's operating system, on top of per-seat user licensing fees for the server as well as the filtering software. With an open source solution you can be up and running with no software and upgrade costs whatsoever.
In the first part of the article we installed SquidGuard, which works through the caching and proxying program Squid. We will now combine the solution with the virus scan engine ClamAV and will get a complete content filtering and virus scanning proxy.Full story »