In addition, the default behavior, along with how expired content should be handled, is
displayed if the original website cannot be reached. For example, if the www.cco.com
website was previously accessed and was downloaded to the cache, but the entry has
expired, the server could be configured to either error out (if the Do Not Return the
Expired Object option is checked) or return the object to the requestor based on the
amount of time since the Time-to-Live (TTL) of the object has expired (the default).
The Time-to-Live of a cache object is the amount of time that the object remains valid in
a cache before it expires and needs to be refreshed. Without TTL settings on cached
objects, stale data could potentially be returned to requesting clients.
FIGURE 8.5 Modifying cache settings.
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8
Enabling ISA Server 2006 as a Web-Caching Server
Configuring Cache Rules
After caching has been enabled on an ISA server, specific rules must be set up to configure
how ISA handles caching traffic. By default, a single Last Default Rule for caching exists
on the server and can be viewed under the Cache Rules tab in the Central Details pane.
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