With the impact spam and viruses are having on businesses, it’s easy to forget about general web usage and ways of controlling it. Unmonitored Internet access in the workplace is costing businesses far too much to be ignored, and without AUPs (acceptable use policies) in place, together with the means to enforce them, Internet misuse can seriously impact on productivity, storage and network bandwidth.

Clearswift’s MIMEsweeper for Web (CMW) could have the answers, as this content security package provides Internet filtering, monitoring and blocking facilities. It offers a simple solution that cuts the time spent customising the product, as it uses a URL database currently comprising a billion web pages covering some 6.5 million sites, and 40 different topics that are deemed inappropriate for business use. This latest version of CMW introduces a modest selection of new features, with overdue support for Windows Server 2003 at the top of the list. The entire product can now be installed on a single server and the remote reporting facilities can finally be run from 2000 and XP Professional workstations. Alas, installation gets off to a very tedious start thanks to the number of prerequisites. You’ll need MDAC, Message Queuing, IIS, .NET and an SQL database, and all must be installed in a specific order. We encountered a number of problems on both 2000 and 2003 test systems and would recommend loading this software on top of a fresh OS install to avoid any conflicts. During this phase, many users will probably find that they require technical assistance.

CMW is implemented as a web proxy and managed with a group of MMC snap-in modules. Web page caching is on offer and CMW supports cache sizes from 500MB to 4GB. For content filtering, it uses a five-pronged approach that starts with authentication via a security policy to determine whether the user is allowed to access the Internet. Next, it checks the requested page against its URL database and, if cleared, it analyses the content to see, for example, if ActiveX is present on the page, or what file types are being requested. For the latter feature, pattern matching is used, so changing the extension of a file being downloaded won’t get it past CMW. Once the content is identified, policies are used to determine how the page is to be handled, and here you can decide to allow it through untouched, clean out any dubious files or block access. CMW also integrates with Symantec’s antivirus software to provide even greater content security measures.

Built around scenarios and classifications, CMW’s policies are powerful tools that can be customised to suit a wide range of requirements. Scenarios provide rules telling CMW what to look for, while classifications tell it what to do. A simple scenario would be blocking downloads of multimedia files over a certain size. The scenario defines the file types and the upper size limit, and the classification contains a block instruction and a warning message to be sent to the user. Categories are used to apply filters based on text analysis, topics from the URL database, a specific list of URLs or PICS (platform for Internet content selection) ratings. The latter enables third party ratings to be applied, and the pre-installed Safeweb and RSACI components provide the tools to implement parental control-style policies on adult material.

Testing showed this product works extremely well with any attempts to access a wide range of sports, gambling or entertainment sites. You could easily stop music downloads, keep smut at bay and generally not waste your Internet connection. Logging and alerting facilities are extensive, as classifications can have email warnings, SNMP traps, NT Alerts or log entries assigned as an action. Reporting is also a strong factor. CMW comes with 18 predefined reports that cover all areas of Internet and user activity, and the results can be exported to a range of formats including PDF, Excel, Word and HTML.

While there are a wide variety of all-in-one solutions on the market that cover content security, anti-spam and antivirus measures, we’ve generally found that, for limiting web access, dedicated products offer the most comprehensive and accurate controls. MIMEsweeper for Web is a fine example of this technology in action.