Configuring cache rules

Microsoft Forefront Threat Management Gateway cache rules specify the types of content stored in the cache and how objects are served from the cache. Configure cache rules using the New Cache Rule Wizard as follows:

1. In the Forefront TMG Management console tree, click Web Access Policy.

2. On the details pane, click the Web Access Policy tab.

3. On the Tasks tab, click Configure Web Caching.

4. On the Cache Rules tab, click New.

5. On the Welcome page of the New Cache Rule Wizard, specify a name for the cache rule. Then complete the wizard as outlined in the following table.

   Page	Field or Property	Setting or Action
   Cache Rule Destination	Add, Edit, Remove	Add, modify or delete a single Web site, a set of Web sites, or a network to which the cache rule should be applied.
   Content Retrieval	Only if a valid version of the object exists in the cache. If no valid version exists, route the request to the server	If a valid cached object is available, serve it from the cache. Otherwise, request the object from the Web site.
   	If any version of the object exists in the cache. If none exists, route the request to the server	Serve any version of the object from the cache. If the object is not cached, request the object from the Web site.
   	If any version of the object exists in the cache. If none exists, drop the request (never route the request to the server)	Serve any version of the object from the cache. If the object is not cached, drop the request and return an error page.
   Cache Content	Never, no content will ever be cached.	Content returned to the user with this rule will never be cached.
   	If source and request headers indicate to cache	Content returned to the user with this rule will be cached if headers indicate caching.
   	Dynamic content	If source and request headers indicate caching, cache retrieved objects even if they are marked as not cacheable.
   	Content for offline browsing (302, 307 responses)	If source and request headers indicate caching, cache content with 302 and 307 codes.
   	Content requiring user authentication for retrieval	If source and request headers indicate caching, cache content requested by authenticated users. Content is then served from the cache without verifying access permissions, and non-authenticated users may be able to access it.
   Cache Advanced Configuration	Do not cache objects larger than	The maximum size of objects cached for this rule.
   	Cache SSL responses	Caches SSL responses for SSL bridged traffic. SSL tunneled traffic is not cached. This effectively means that you can cache SSL traffic in reverse caching scenarios, where internal Web sites are published over SSL, and the SSL request is terminated on the Forefront TMG firewall. Outgoing SSL requests to the Internet cannot be cached.
   HTTP Caching	Enable HTTP caching	Cache requested HTTP objects.
   	Set TTL of objects (% of the content age)	Keep HTTP objects valid in the cache according to TTL settings. TTL settings are based on the TTL defined in the response header and the TTL boundaries defined in the cache rule. The percent of the content age is a percentage of the time of the content's existence. The higher the percentage, the less frequently the cache is updated.
   	No less than	The minimum amount of time that the HTTP object remains in the cache.
   	No more than	The maximum amount of time that the HTTP object remains in the cache.
   	Also apply these TTL boundaries to sources that specify expiration	Even if the source contains expiration data, its TTL will be overridden if it is not within the specified TTL boundaries.
   FTP Caching	Enable FTP caching	Cache requested FTP objects.
   	Time-To-Live for FTP objects	The object expires in the cache when the TTL runs out, and content is returned from the cache in accordance with the negative caching configuration settings.