If you are looking for a little more than simple content filtering, it is worth taking a look at WebWasher. Aimed at the medium to large business, it provides extensive content filtering and a number of other valuable features.
Installation is not as straightforward as it might be; compared with some of the more complex products in this Group Test, it requires a lot of user intervention to install and configure. However, there is a handy quick start guide and a comprehensive reference manual (both in PDF format) to help you through it. One benefit of WebWasher is that it is designed to sit on Windows, Solaris and Linux platforms.
Management of WebWasher is through a browser-based GUI. Because of the number of options you have for configuration, this does appear rather cluttered, and a more usable interface would be welcome. Thankfully, the product is fully integrated with most existing user authentication methods such as LDAP and NTLM.
WebWasher offers a wide range of different content filtering options. As well as filtering out such hazardous or bandwidth-heavy objects such as .EXE and MP3 files, it also has an optional virus filter which works with most third-party anti-virus products.
It can also be instructed to extract files from an archive such as a ZIP file and scan their content. One feature that is bound to infuriate a number of companies is the option to block advertisements, including those annoying pop-ups as well as banner ads. Banned keywords can be specified; WebWasher also checks the content of the metatags, which means that a web site can be blocked without having to be loaded.
Another extremely useful option is the ability to remove users' footprints from web sites they have visited, including cookies. While this might not seem important, it is possible to compile an accurate description of your network from these, including any security weaknesses.
URL blocking can either be specified by your own database, or via the DynaBLocator database provided by WebWasher. This database is automatically updated.
WebWasher provides extensive reporting and alerting capabilities. As well as summaries, it also performs traffic analysis, which means you can monitor network usage and fine tune who is allowed to access the internet and when.
Despite a few hassles during installation, WebWasher is well worth considering as an internet filtering tool given the extras that come with it - especially the ad blocker.