Most web browsers do not provide the ability to selectively enable and disable access to certain web sites. There are situations, however, where restricting web site access can be beneficial. For example, parents of young children may want to block access to adult-oriented sites or alternatively may want to only allow access to a set of web sites that they have pre-approved. Access control may seem like an important enough feature that it would be present in all web browsers. However, access control is only recently available in Internet Explorer 4.0 and not available in Netscape Navigator. Since all HTTP requests are sent through the filtering system, an access control system can be implemented using filters which reject access to particular web sites.