Rules are set by a rule provider at the client, and deferred actions are carried out by the provider action code. The default rule provider is code within the Microsoft Exchange Client that works with Microsoft Exchange Server to implement the Inbox Assistant, the Out of Office Assistant, and other folder assistant tools on the client menu and toolbar.
Rules processing occurs in the following sequence:
A rule provider — either the Microsoft Exchange Client or a third-party provider — sets a rule on a folder. The rule is given a sequence number and stored in the folder's rule table.
The server rules engine interprets the rules in the table.
The server rules engine evaluates the rule condition against items arriving in the Inbox and initiates actions for conditions that are TRUE.
The server creates deferred action messages (DAMs) in the mailbox's Deferred Action folder for a rule on a mailbox or private folder if the server cannot initiate the action or if the action is of the type deferred action.
The corresponding provider code at the client retrieves any DAMs, either immediately or when the client reconnects.
For deferred actions, the client then accesses the message in the mailbox or folder and carries out the action.
Rules components in Microsoft Exchange Server and client
The rules provider in the Microsoft Exchange Client allows custom action DLLs to be registered and called when their particular rules are fired.
