Web caching and SSL offloading
FortiGate web caching is a form of object caching that accelerates web applications and web servers by reducing bandwidth usage, server load, and perceived latency. Web caching supports caching of HTTP 1.0 and HTTP 1.1 web sites. See
RFC 2616 for information about web caching for HTTP 1.1.
| Web caching does not cache audio and video streams including Flash videos and streaming content. Web caching caches compressed and non-compressed versions of the same file separately. If the HTTP protocol considers the compressed and uncompressed versions of a file the same object, only the compressed or uncompressed file will be cached. |
Web caching involves storing HTML pages, images, servlet responses and other web-based objects for later retrieval. You can also go to System > Config > Advanced > Disk Management to view the storage locations on the FortiGate unit hard disks. You can change the default storage configuration using the config wanopt storage command.
There are three significant advantages to using web caching to improve HTTP and WAN performance:
• reduced bandwidth consumption because fewer requests and responses go over the WAN or Internet.
• reduced web server load because there are fewer requests for web servers to handle.
• reduced latency because responses for cached requests are available from a local FortiGate unit instead of from across the WAN or Internet.
You can use web caching to cache any web traffic that passes through the FortiGate unit, including web pages from web servers on a LAN, WAN or on the Internet. You apply web caching by enabling the web caching option in any security policy. When enabled in a security policy, web caching is applied to all HTTP sessions accepted by the security policy. If the security policy is an explicit web proxy security policy, the FortiGate unit caches explicit web proxy sessions.
This section contains the following topics: