Introduction

Every member of every domain in an active directory holds information that specific domain controllers can access. This information can be implemented to search for AD objects even without the domain name. This is made possible by the global catalog.

Definition

A global catalog is a feature of the active directory which stores partial attributes of other domains in a particular forest. It also allows domain controllers to access any active directory objects from the forest, even if that AD object does not belong to that domain controller’s domain. Under normal circumstances, a global catalog has two main functions:

• The global catalog makes the forest in an active directory transparent and accessible to an external user who can find any AD object within the forest without having to search for its domain. This increases the efficiency of information accessibility.
• The global catalogue also carries out an authentication process as the domain controller will verify the authentication request. It checks if the user is part of any multi-domain environment, such as universal groups. A global catalogue is permitted to access information from such universal group memberships and locate the targeted users.

Block Diagram

Steps to set up a Global Catalog

Under normal circumstances, the first domain controller in a domain is deployed as a global catalogue. However, if the administrator wants to add global catalogs, they have to select particular domain controllers and choose the global catalog checkbox in the server’s NTDS Settings. It can also be typed in as:

Set-object -Identity (Get-ADDomainController -Server <SERVER>).NTDSSettingsObjectDN -Replace @{options=’1′}

Advantages of a Global Catalog

The global catalog, maintained by the Active Directory Domain Services (AD DS), is handier while working in a multi-domain environment. Any user can use the global catalogue to access available network resources from a vast collection of resources present in the forest. This feature reduces the time consumed and increases productivity.