Microsoft Exchange Server rules are evaluated against every message that comes into a folder or mailbox. When the message matches the rule condition, the rule fires and the rule action is executed. The server rules engine offers a fixed set of actions that it can carry out in the information store process on the server, but some actions must be carried out on the client. For instance, moving a message to a folder in another information store can be carried out only on the client.
The following actions are always passed to the client for execution: