Active Directory Components and Exchange Server Integration
Active Directory information is divided into four partitions: domain, configuration, schema, and application. These directory partitions are the replication units in AD DS.
A domain partition contains all objects in the domain’s directory. Domain objects replicate to every domain controller in the domain, and include user and computer accounts and groups. A subset of the domain partition replicates to all domain controllers in the forest that are global catalog servers. If you configure a domain controller as a global catalog server, it contains a complete copy of its own domain’s objects and a subset of attributes for every domain’s objects in the forest.
The configuration partition contains configuration information for AD DS and applications, including
Active Directory site and site link information. In addition, some distributed applications and services store
information in the configuration partition. This information replicates through the entire forest, so that
each domain controller retains a replica of the configuration partition.
When application developers choose to store application information in the configuration partition, the
developers do not need to create their own mechanism to replicate the information. The configuration
partition stores each type of configuration information in separate containers. A container is an Active
Directory object, similar to an organizational unit (OU) that is used to organize other objects.
The schema partition contains definition information for all object types and their attributes that you can
create in AD DS. This data is common to all domains in the forest, and AD DS replicates it to all domain
controllers in the forest. However, only one domain controller maintains a writable copy of the schema. By
default, this domain controller, known as the Schema Master, is the first domain controller installed in an
Active Directory forest.
An administrator can create application partitions manually, and an application can automatically create
partitions during its installation process. Application partitions hold specific application data that the
application requires. The main benefit of application partitions is replication flexibility. You can specify
the domain controllers that hold a replica of an application partition, and these domain controllers can
include a subset of domain controllers throughout the forest. Exchange Server 2013 does not use
application partitions to store information.
Exchange Server 2013 and AD DS Partitions Integration
To ensure proper placement of Active Directory components in relation to computers that are running
Exchange Server, you must understand how Exchange Server 2013 communicates with AD DS and uses
Active Directory information to function. AD DS stores most Exchange Server 2013 configuration
An Exchange Server organization and an Active Directory forest have a one-to-one relationship. You
cannot have an Exchange Server organization that spans multiple Active Directory forests. You also cannot
have multiple Exchange Server organizations within a single Active Directory forest.
Note: In Exchange Server 2013, you can also add Office 365 domain to the Exchange
Administration Center (EAC) console. This enables you to manage multiple organizations from
a single management console.
The Exchange Server 2013 installation process modifies the schema partition to enable the creation of
Exchange Server-specific objects. The installation process also adds Exchange Server-specific attributes to
existing objects. For example, the installation process updates user objects with additional attributes to
describe storage quotas and mailbox features.
The configuration partition stores configuration information for the Exchange Server 2013 organization.
Because AD DS replicates the configuration partition among all domain controllers in the forest,
configuration of the Exchange Server 2013 organization replicates throughout the forest. The
configuration partition includes Exchange Server configuration objects, such as global settings, email
address policies, transport rules, and address lists.
The domain partition holds information about recipient objects. This includes mailbox-enabled users,
and mail-enabled users, groups, and contacts. Objects that are mailbox-enabled or mail-enabled have
preconfigured attributes, such as email addresses.
• When you install Exchange Server 2013, the email attributes for mail-enabled and mailbox-enabled
objects replicate to the global catalog. In the context of Exchange Server, global catalog is used for
the following: The global address list (GAL) is generated from the recipients list in an Active Directory
forest’s global catalog.
• Exchange Server 2013 transport service access the global catalog to find the location of a recipient
mailbox when delivering messages.
• Client Access servers access the global catalog server to locate the user Mailbox server and to display
the global address list to Microsoft Office Outlook®, Microsoft Outlook Web App, or Exchange
Note: Because of the imp ortance of the global catalog in an Exchange Server organization,
you must deploy at least one global catalog server in each Active Directory site that contains
an Exchange 2013 server. You must deploy enough global catalog servers to ensure adequate
performance. Exchange Server 2013 does not use Read-Only Domain Controllers(RODCs) or
RODCs that you configure as global catalog servers (ROGC). This means that you should not
deploy an Exchange 2013 server in any site that contains only RODCs or ROGCs