Active Directory

Active Directory (AD) is a technology created by Microsoft to provide network services including LDAP directory services, Kerberos based authentication, DNS naming, secure access to resources, and more. Active Directory uses a single Jet database which a variety of services and applications can use to access and store a variety of information. Active Directory is used by system administrators to store information about users, assign security policies, and deploy software. AD is used in many different types and size of environments from the very small (a dozen users) to hundreds of thousands of users in a global environment.

Active Directory is a technology created by Microsoft that provides a variety of network services, including:

  • LDAP-like directory services
  • Kerberos-based authentication
  • DNS-based naming and other network information
  • Central location for network administration and delegation of authority
  • Information security and single sign-on for user access to networked based resources 
  • The ability to scale up or down easily 
  • Central storage location for application data
  • Synchronization of directory updates amongst several servers 

Using the same database, for use primarily in Windows environments, Active Directory also allows administrators to assign policies, deploy software, and apply critical updates to an organization. Active Directory stores information and settings in a central database. Active Directory networks can vary from a small installation with a few computers, users and printers to tens of thousands of users, many different domains and large server farms spanning many geographical locations.

Structure of
Active Directory:
  1. Objects: Everything that Active Directory tracks is considered an object. An object is any user, system, resource, or service tracked within Active Directory. The generic term object is used because Active Directory is capable of tracking a variety of items, and many objects can share common attributes.
          An Active Directory structure is a hierarchical framework of objects. The objects fall into two broad categories: resources                  (e.g., printers) and security principals (user or computer accounts and groups). Security principals are Active Directory objects              that are assigned unique security identifiers (SIDs) used to control access and set security.
    2.   Sites: A Site object in Active Directory represents a physical geographic location that hosts networks.It contain objects called              subnets.Sites can be used to assign Group Policy Objects, facilitate the discovery of resources, manage active directory                      replication, and manage network link traffic. Sites can be linked to other Sites. Site-linked objects may be assigned a cost value              that represents the speed, reliability, availability, or other real property of a physical resource. Site Links may also be assigned a              schedule.