Server-based vs. client-based rules

You can divide rules, whether created with Inbox Assistant or Rules Wizard, into two types - server-side and client-only. Server-side rules are handled entirely by the Exchange Server, independent of the state of the Outlook client. Client-only rules do not execute until the user who created the rule logs in to the Outlook client with the same profile used to create the rule.

One myth is that you can only use Inbox Assistant to create server-based rules. This is not true. Some rules created with IA run only on the client. Many rules created with Rules Wizard run from the server. Whether a rule is server-based or client-based depends, not on the tool you use to create it, but on the exact conditions and actions for that rule.

Certain rules are always client-only - those that involve some element from the Outlook client that does not exist on the Exchange Server. The following table classifies these according to whether they depend on Outlook features, client files or the mail profile. The last group contains something of a surprise: A rule to copy to a public folder fires only when the client is logged in with the profile that created the rule.

TIP: Try forwarding the message to the public folder instead. That rule always fires on the server.

When you create a rule, the Rules Wizard stores the rule settings (conditions, actions, and exceptions) in a .rwz file with the same name as the user's profile. For rules for incoming messages, it also stores that information in the Inbox folder itself, with an indicator of what profile created the rule. This means that the details of the rule are available to the server.

When a message arrives, the server compares it with the list of rules. If the server can execute the rule, it does so. If not, it places a deferred action message (DAM) in a hidden Deferred Action folder in the mailbox.

When the user runs Outlook, the client checks the Deferred Action folder and examines each DAM. If the rule was created with the current profile, Outlook carries out the actions indicated in the DAM. This helps explain why rules may fire in an order different from that listed in the Rules Wizard: If the user is not logged in, rules that run on the server execute first, while client-only rules don't fire until the next time the user runs Outlook with the appropriate profile.

Note that if a mailbox is over its size limit, it cannot execute any rules that will send replies or forward items. 

Portions of this article first appeared in the April 1999  issue of the Exchange & Outlook Administrator newsletter.

More Information

Home | What's New | Exchange Server | Outlook | Utilities | Bookstore
About Slipstick | Feedback | Privacy Policy | Archived Pages | Link to Us | Advertise

Hosted by Intermedia.net