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St. Bernard's iPrism Clears Up Web Filtering Job for Small Organizations: Page 2 of 5

Blocking Positions

A sleek Pentium 500-MHz appliance running FreeBSD and with 128 MB of RAM, iPrism almost fits in a briefcase and can act as a standalone server, bridge or router. You can install and configure iPrism from any workstation with a Web browser and a JVM (Java Virtual Machine).

I placed the appliance between two switches in Network Computing's Syracuse University Real-World Labs® to act as a bridge, passing traffic from one subnet to another. IPrism interrogated each packet as it passed through.

iPrism offers three basic monitoring and blocking profiles to start with: PassAll, MonitorOffensive or BlockOffensive. Every profile contains URL access lists that can be viewed and/or modified with a right-mouse click. You can create new access lists to identify and block sites specific to your organization and specify access based on the day and time.
The site lists are compiled by St. Bernard and updated on a subscription basis -- you can choose a one-year or three-year subscription. The administrator can set iPrism to get Filter Lists manually or automatically at a specified time every day.

Reality Check
Web filtering typically relies on keyword or phrase blocking or URL or IP address blocking.

The first method looks for objectionable words or phrases, blocking or passing a page to the desktop based on the number of suspect words or phrases found. This method is slow and can result in many false positives.

URL- or IP-based filtering is less time-consuming and can be easily applied to other types of Internet traffic, including FTP, ICQ, IRC, RTSP and telnet. But IP address blocking may be too broad. URL-based filtering is more granular but is only as good as the database containing the URLs. If you choose a URL/IP filter like iPrism, you'll need a maintenance contract to guarantee that the database is updated frequently.

NB: Blocking too much content can frustrate users; blocking too little may lead to harassment and embarrassment. Finding a balance requires site-specific configuration, ongoing monitoring and maintenance. Choose a product with easy-to-use GUIs, good reporting and a maintenance contract with regular updates.