URL filtering can be enabled globally or per virtual service.
Here are the steps in the Webui (ArrayOS 6.4 or later).
To enable globally: Under Proxy -> Caching Proxy -> Global URL Filter -> check “enable”
To enable for a virtual service (VIP): Under Load Balance -> Virtual Services -> URL Filter -> check “enable”
When enabling this feature, you’ll have an option to configure URL Filtering in either passive mode or active mode.