System policies are used on Exchange objects typically thought of as server-side, such as store databases and servers. Exchange supports three classes of system policies: mailbox store, public folder store, and server.
System policies use an apply-time implementation to effect configuration changes. An administrator creates a policy, defines the settings that policy implements, associates that policy with one or more objects of the same class, and then applies the policy. The objects with a policy applied to them list the applicable policies and disable the settings that the policy overrides. This enables administrators to prevent further changes.
Each type of system policy is defined by setting properties on one or more tabs. The smallest possible policy is the set of properties on a single tab. The policy types and their tabs with descriptions are as follows: