The Active Directory in the Windows 2000/2003 Server has the following Roles in it:
FSMO Roles (Flexible Single Master Operation)
In a forest, there are at least five FSMO roles that are assigned to one or more domain controllers. The five FSMO roles are:
1. Schema Master:
The schema master domain controller controls all updates and modifications to the schema. To update the schema of a forest, you must have access to the schema master. There can be only one schema master in the whole forest.
2. Domain Naming Master:
The domain naming master domain controller controls the addition or removal of domains in the forest. There can be only one domain naming master in the whole forest.
3. Infrastructure Master:
The infrastructure is responsible for updating references from objects in its domain to objects in other domains. At any one time, there can be only one domain controller acting as the infrastructure master in each domain.
4. Relative ID (RID) Master:
The RID master is responsible for processing RID pool requests from all
domain controllers in a particular domain. At any one time, there can be only one domain controller acting as the RID master in the domain.
5. PDC Emulator:
The PDC emulator is a domain controller that advertises itself as the
primary domain controller (PDC) to workstations, member servers, and domain controllers that are running earlier versions of Windows. For example, if the domain contains computers that are not running Microsoft Windows XP Professional or Microsoft Windows 2000 client software, or if it contains Microsoft Windows NT backup domain controllers, the PDC emulator master acts as a Windows NT PDC. It is also the Domain Master Browser, and it handles password discrepancies. At any one time, there can be only one domain controller acting as the PDC emulator master in each domain in the forest.
You can transfer FSMO roles by using the Ntdsutil.exe command-line utility or by using an MMC snap-in tool. Depending on the FSMO role that you want to transfer, you can use one of the following three MMC snap-in tools:
Active Directory Schema snap-in
Active Directory Domains and Trusts snap-in
Active Directory Users and Computers snap-in
If a computer no longer exists, the role must be seized. To seize a role, use the Ntdsutil.exe utility.
Understanding the Active Directory Schema
Windows 2000 and Windows Server 2003 Active Directory uses a database set of rules called “Schema”. The Schema is defines as the formal definition of all object classes, and the attributes that make up those object classes, that can be stored in the directory. As mentioned earlier, the Active Directory database includes a default Schema, which defines many object classes, such as users, groups, computers, domains, organizational units, and so on. These objects are also known as “Classes”. The Active Directory Schema can be dynamically extensible, meaning that you can modify the schema by defining new object types and their attributes and by defining new attributes for existing objects. You can do this either with the Schema Manager snap-in tool included with Windows 2000/2003 Server, or programmatically.