Active Directory runs on Windows Server and allows administrators to manage permissions and access to network resources. Active Directory stores data as objects. In order for a directory like AD to work, a protocol for querying, maintaining, and authenticating access to it must be in place. LDAP, or Lightweight Directory Access Protocol, is one such protocol. It is a client-server protocol.
The central protocol of AD is LDAP. When a client searches for a particular object in AD (such as a user or a printer), LDAP is used to query related objects and return the correct results.
