The Global Catalog service on a DC server

12.5.2009    |    komentáře   komentářů: 0

Example of enabling or disabling the Global Catalog service on a Domain Controller Server 2003/2008

What is the Global Catalog?

The Global Catalog (GC) contains selected information about objects throughout the tree or forest. Domain Controller (DC)that holds a copy of the global catalog is called a Global Catalog Server (in other words, a GC can run only on a DC). There can be multiple global catalogs, with multimaster replicationbetween them. GCs are often placed in different site, but remember the resulting replication traffic, which can be considerable.

GC therefore allows directory information to be found regardless of its domain within the forest. Its second function is to provide information about membership in universal groups (universal group membership), which is needed during logon. If a global catalog is unavailable during logon, the user can log on only locally to the computer. One way to work around this without running a GC is to enable universal group membership caching (UGMC) for that site. The DC then stores the information locally. At the user's first logon, it queries the global catalog and stores the returned values in a cache, where they are retained and refreshed. Subsequent logons use this cached information.

Note: Enabling UGMC is done through Active Directory Sites and Services, where you click the relevant site and then right-click NTDS Site Settings and select Properties.

Enabling the Global Catalog service on a DC server?

  1. On the domain controller where you want to enable the global catalog, open the Active Directory Sites and Services snap-in. To launch the snap-in, on the Startmenu, click Programs, then Administrative Tools, and click Active Directory Sites and Services.
  2. In the tree view, expand Sites, then double-click sitename, containing the DC server where you want to enable the GC service.
  3. Double-click Servers and click the relevant DC server, then right-click NTDS Settings and select Properties.
  4. On the Generaltab, select Global catalog, to enable the GC service on the selected server.
  5. Restart the domain controller.

Disabling the Global Catalog service on a DC server?

  1. On the domain controller where you want to disable the global catalog, open the Active Directory Sites and Services snap-in. To launch the snap-in, on the Startmenu, click Programs, then Administrative Tools, and click Active Directory Sites and Services.
  2. In the tree view, expand Sites, then double-click sitename, containing the DC server where you want to disable the GC service.
  3. Double-click Servers and click the relevant DC server, then right-click NTDS Settings and select Properties.
  4. On the General, clear Global catalog, which enables the GC service on the selected server.
  5. Restart the domain controller.

Adding attributes to the Global Catalog (GC)

The Global Catalog service normally provides information about a predefined set of AD attributes. You can add other AD attributes that you want to make readable through the GC service. See the links to Microsoft.com

Link to Microsoft.com

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