Client-side vs. Server-side Rules

What are rules in Outlook and how can they help you manage your email? Simply put, rules are conditions set upon incoming and outgoing messages. When one or more of these conditions are met, Outlook takes an action that you specify. You can create rules from a template, from a message or by using your own custom conditions. There are two types of rules that Outlook uses: Client- rules and server rules. These rules perform very differently. Rules that have actions that require Outlook are client-side rules and only run if Outlook is running. Rules that do not require Outlook to process are considered server-side rules. Let’s look at the two rule types more in-depth.

Client Rules

The most important thing to know about a client-side rule is that Outlook must be running in order for the rule to work. If Outlook is not running, a client-side rule cannot be processed. Client rules also will not run unless the same user who created the rule logs into Outlook.

Creating rules in Outlook is simple. In Outlook, click the File tab and then click the Manage Rules and Alerts button. By default, the Email Rules tab is selected. To create the rule, click New Rule. This will launch the Rules Wizard.

In the Rules Wizard you can select from a set of pre-designed templates or use a blank rule to handle messages the way you want them handled.

Some examples of a client rule include the following:

  • Moving mail from a company such as to a folder called ‘Fabrikam’

  • Moving specific messages to a PST file

  • Play a specific sound when mail from your uncle Jim arrives

It’s also important to note that when it comes to client rules and server rules, the Exchange Server will look at incoming messages and apply its rules first if applicable. Afterward, client rules are applied when Outlook is running. Also, if a server rules moves a message when Outlook is not running, a client rule that exists in Outlook and that applies to the message may not run. This is known as a rule conflict and is discussed more later. Also, if a mailbox exceeds its size limit, rules that send replies or forward items will not run.

Rules created on the client are stored in a Filename.RWZ file where Filename is the name of the user that created the rule. You can also check which rules are client rules by clicking the Rules button under the Move section of the Home menu on the Ribbon. Then click Manage Rules and Alerts. Any rules that run on the client with have “(client –only)” appended to the end of the rule.


When you create a rule you are given the option to run the rules for all emails in your inbox. If you missed this checkbox, you can always go back and run the rules anytime. Go to the Manage Rules and Alerts dialog and select Run Rules Now.

Server Rules

Server rules are handled entirely by the Exchange Server and are applied to messages that arrive in your inbox even when Outlook isn’t running. Server rules handle rule operations that don’t require the Outlook client. Server rules are created two ways – by using Outlook Web Access (OWA) or by using Outlook. Rules created in OWA are always saved as server-side rules.

Some examples of a server rule include:

  • Changing the importance of a message

  • Moving the incoming message to a specific folder on the user’s mailbox

  • Deleting a message

To create a rule using OWA, go to the navigation pane and click Rules and in the Rules area toolbar, click New. This will open the Edit Rule dialog box. You can also right click any email message in OWA and left click Create Rule.

To create a server rule in Outlook, select an email you have already received. Click the Home tab in the ribbon if it is not already selected. In the Move group select Rules then Create Rule.

Rule Conflicts

Rules conflicts happen when you have more than one rule that will affect an incoming message. Let’s say, for example, you receive an incoming email from “John Doe” and the subject line is “Widget report for last week”. Let’s say you have two rules set – one that looks for mail from John Doe that forwards the mail to a subfolder in your inbox called “John Doe” and another rule that’s set to look for they keyword “Widgets” in the subject of a message.

If these are both client-side rules, the rule listed first in the rules list will take precedence. The mail from John Doe will end up in the John Doe subfolder and not the Widgets folder. If new mail was received from “Jane Doe” with ‘Widgets’ in the subject then the item would be moved to the Widgets subfolder since the criteria for the first rule was not met.

Let’s say that you have a client-only rule set to look for the word “Widgets” in the subject line and a server-side rule set to look for mail from “John Doe” and move it to the “John Doe” folder. Let’s also say Outlook is not running. When the mail is received, Exchange processed the server rule for “John Doe” and moves it to the “John Doe” folder. When you launch Outlook, the rules are applied, but because the new mail is not in the inbox, the “Widgets” rule is not processed and the email remains in the “John Doe” folder.


For more information on server and client rules on the Mac for Office 2011, see the following blog post.

Special thanks to Will Buffington and Melissa Shellito

Comments (2)

  1. Tony Benisch says:

    Our organization is using outlook with Exchange 2013. In outlook I created a mail rule, in which I specified the ‘server’ to send a response using a template I created. The rule is suppose to fire on every message received to inbox in which I created the rule. Unfortunately, the rule is only firing and sending the template response to emails being sent to the inbox from email addresses within my organization. Ive sent multiple emails to the inbox using outside email addresses, they are received, but the template reply is never sent out. Im thinking there is some type of configuation on the exchange server that might be preventing the reply being sent outside organization

    1. Per, you need to configure the Set-RemoteDomain parameter “AutoReplyEnabled”.

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