| FSMO Role | Description |
| Schema Master | The schema master role belongs to only one domain controller in the entire forest. The schema is simply a schematic, or blueprint, of all Active Directory objects and their attributes. The schema determines what kinds of objects can be stored in the directory and what attributes define those objects. Any modifications made to the schema must be made on the domain controller holding the schema master role. |
| Domain Naming Master | The domain naming master role belongs to only one domain controller in the forest. The domain naming master controls the addition and removal of domains in the forest. |
| Relative ID (RID) Master | The RID master manages the distribution of RID numbers to other domain controllers. When a domain controller generates a new security ID (SID) for a new user, computer, or group account, a domain security ID and a RID number are used. The RID master makes certain that no two domain controllers have the same or overlapping RID numbers. Each domain in the forest has one RID master. |
| PDC Emulator | Windows 2000 domains that have Windows NT BDCs still in operation (mixed mode) and Windows 2000 domains that have downlevel clients (such as 9x and NT) expect a PDC to be present on the network. The PDC Emulator role is played by one domain controller in each domain to “act like” a Window NT PDC. |
| Infrastructure Master | The Infrastructure master role, which is held by one domain controller in each domain, updates group members as necessary. For example, when the membership of a particular group changes, the Infrastructure master updates the group to ensure that changes are processed appropriately. |
Hyaking Tech
It's Technical Site
