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Dynamic Distribution Groups

  • Article

Applies to: Office 365 for enterprises, Live@edu

The cloud-based service supports a special kind of distribution group called a dynamic distribution group. Unlike the static membership list of a regular distribution group, also known as a public group, the membership list for a dynamic distribution group is calculated every time a message is sent to the group. This calculation is based on filters and conditions you define when you create the group. When an e-mail message is sent to a dynamic distribution group, it is delivered to all recipients in the organization that match the filters and conditions you defined.

When would you use a dynamic distribution group?

Suppose you are using the cloud-based service at a university. Student enrollment in the various academic departments changes every semester, even in the middle of the semester. You can populate the Department field on the student mailboxes, and then use dynamic distribution groups to filter the students based on their department. That way you don't have to manually add or remove students from the departmental distribution groups.

In addition, dynamic distribution groups are useful if you want to conceal the members of a distribution group, because the group membership is never displayed to senders, recipients, or other users.

Dynamic distribution groups are also useful in a cross-premises environment when your organization uses both the cloud-based service and on-premises Microsoft Exchange servers on which you have large distribution groups. Because dynamic distribution groups are expanded into individual recipients at the destination, only a single copy of the message is transmitted between the cloud-based service and the on-premises Exchange organization. This helps reduce message traffic between the cloud-based service and the on-premises Exchange organization and speeds message delivery for large distribution groups.

How do I define filters and conditions when I create a dynamic distribution group?

You have two options: precanned filters that use the IncludedRecipients parameter and customized filters that use the RecipientFilter parameter. You can't use customized filters and precanned filters at the same time.

Both filtering methods are implemented by using Windows PowerShell. Dynamic distribution groups don't appear in the Exchange Control Panel.

Here's a quick description of the differences between the two methods.

Filtering method Filterable attributes Filter operators

Precanned filters that use the IncludedRecipients parameter

Limited to:

  • Recipient type
  • Company
  • Custom Attribute fields
  • Department
  • State/Province

Limited to the following:

  • When an attribute value is specified, the EQV operator is used, as in "Department equals Sales". Wildcards and partial matches aren't supported.
  • When multiple values of the same attribute are specified, the OR operator is used, as in "Department equals Sales OR Marketing".
  • When multiple attributes are specified, the AND operator is used, as in "Department equals Sales AND Company equals Contoso".

Customized filters that use the RecipientFilter parameter

Any available recipient attributes can be used.

Any available Windows PowerShell conditional operator can be used. Wildcards and partial matches are supported.

What's next?