This is the percentage of URL-category lookups that were resolved from the gateway's own local UFP (URL Filtering Protocol) cache rather than requiring a fresh round-trip query to the external URL-filtering server (e.g. Websense or SurfControl). An admin watching this ratio helps judge whether the local cache is sized and tuned well: a low hit ratio means most HTTP requests are paying the extra latency of an external lookup, which directly slows down web browsing for users behind the gateway. A hit ratio in the 60-80% range is typical on a gateway with a reasonably warmed cache and a stable set of frequently visited sites.