An apparatus method and system are described for categorizing Uniform Resource Locators (URLs) when accessing the Internet from a client. A request message is generated to request categorization of a specified URL, and a category is provided in a reply message. The specified URL and the category are added to a category cache. In a second or subsequent instance of a URL request referring to the specified URL, the category is determined from the category cache. This reduces communication traffic in a network such as the Internet.