Explanation
When you enable URL Filtering, all web traffic is compared against the URL Filtering database, PAN-DB, which contains millions of URLs that have been grouped into about 65 categories.

A static routing protocol requires that routes be created and updated manually on a router or other network device. If a static route is down, traffic can't be automatically rerouted unless an alternate route has been configured. Also, if the route is congested, traffic can't be automatically rerouted over the less congested alternate route. Static routing is practical only in very small networks or for very limited, special-case routing scenarios (for example, a destination that's used as a backup route or is reachable only via a single router). However, static routing has low bandwidth requirements (routing information isn't broadcast across the network) and some built-in security (users can route only to destinations that are specified in statically defined routes).