Global Catalog Server
Applies To: Windows Server 2008
The global catalog is a distributed data repository that facilitates searches and logons in an Active Directory forest. The Active Directory replication system builds global catalog data automatically.
One or more domain controllers in an Active Directory forest host the global catalog. The domain controllers that host the global catalog are called global catalog servers.
Users and applications can use the global catalog to locate objects in any domain in the forest by searching for an attribute of the object. For example, an administrator can use the global catalog to search for a user's last name to locate that user's account in the forest. A user can also use the global catalog to search the forest for a list of printers that are organized by location.
The global catalog facilitates logons by ensuring that membership in universal groups from all domains is represented in the user's access credentials (also known as the access token).
The following is a list of all aspects that are part of this managed entity:
Domain controllers on a network must contact global catalog servers to perform certain functions. For example, if an administrator adds a user from another domain in the forest to a domain local group in the local domain, a global catalog server is used to obtain the appropriate information to be added for the user. If the local domain controller is not a global catalog server, it locates another domain controller that is hosting the global catalog to obtain the appropriate information.