If your client uses ICAP, you can filter Web sites based on Uniform Resource Locator (URL) addresses. Symantec Protection Engine uses URL categories to restrict access to the Web sites that may contain inappropriate content. You can filter outgoing requests like search engine queries and URL addresses.
Symantec Protection Engine includes the predefined URL categories that consist of URLs containing related subject matter. Symantec Protection Engine 7.0 and later is integrated with an enhanced URL database. The number of predefined URL categories have been increased following the current online trends like social networking, search engines, blogs, and online shopping. This increase in the categories lets you block access to more specific topics.
You can also create custom categories called local categories. When you place a category into the Deny Access list, access is denied to any URL that is contained in that category.
A description of the scanning modes is as follows:
When you select audit mode, Symantec Protection Engine notifies the ICAP client of all the Symantec, CAIC, and Local categories that the requested URL falls under. Based on this information, the ICAP client handles the application of the filtering policies. The client determines whether to block the site and deny access.
When Symantec Protection Engine operates in the filtering mode, Symantec Protection Engine handles the application of URL filtering. You configure the types of URL that you want to deny. Based on your configuration, Symantec Protection Engine determines whether to deny access for each request. Symantec Protection Engine returns to the user an "Access Denied" message when it blocks access to a URL.