Applies To: Windows Server 2008, Windows Server 2008 R2, Windows Server 2008 R2 with SP1
When the AD RMS clusters in each forest were configured to support users in other forests by following the example provided in Configuring AD RMS Across Forests, contact items were created for each user in the other forests. Exchange Server 2010 uses the msDS-SourceObjectDN attribute of these contacts to associate the contact item with the user’s AD RMS root cluster. The msDS-SourceObjectDN attribute is part of the base Active Directory schema and contains the string representation of the distinguished name of the object in another forest that corresponds to this object. This attribute is used for distribution group expansion, and setting this attribute is required to enable such Exchange Server 2010 features as prelicensing across forests.
To enable AD RMS to associate a contact item with the user’s AD RMS root cluster, an Active Directory Domain Services administrator must set the msDS-SourceObjectDN attribute of each user contact to the distinguishedName attribute of its target user. For example, if a contact item in the forest contoso.com represents a user named Nicole Holiday in the forest named cpandl.com, set the distinguishedName attribute of the contact object of user object for Nicole Holliday in cpandl.com, such as “CN=Nicole Holliday,CN=Users,DN=cpandl,DN=com”.