If you decide that you want your Proxy Server to cache HTTP documents, determine whether it should always do an up-to-date check for documents in the cache or whether it should check based on a Cache Refresh setting (up-to-date check interval). For HTTP documents, a reasonable refresh interval would be four to eight hours, for example. The longer the refresh interval, the fewer the number of times the proxy connects with remote servers. Even though the proxy does not do up-to-date checking during the refresh interval, users can force a refresh by clicking the Reload button in the client. This action makes the proxy force an up-to-date check with the remote server.
You can set the refresh interval for HTTP documents on either the Set Cache Specifics page or the Set Caching Configuration page. The Set Cache Specifics page enables you to configure global caching procedures, and the Set Caching Configuration page enables you to control caching procedures for specific URLs and resources.