Web caching can be applied to any HTTP or HTTPS traffic by enabling web caching in a security policy that accepts the traffic. This includes WAN optimization and explicit web proxy traffic. Web caching caches all HTTP traffic accepted by a policy on TCP port 80.

You can add web caching to a WAN optimization security policy to combine web caching with WAN optimization for any WAN optimization security policy. This includes manual, active and passive WAN optimization policies and WAN optimization tunnel policies. You can enable web caching on both the client-side and the server-side FortiGate units or on just one or the other. For optimum performance, you can enable web caching on both the client-side and server-side FortiGate units. In this way, only uncached content is transmitted through the WAN optimization tunnel. All cached content is access locally by clients from the client side FortiGate unit.