2.2.5 Directory Replication Service Remote Protocol
The Directory Replication Service Remote Protocol is an RPC protocol for replication between DCs and management of AD. The protocol consists of one RPC interface, named drsuapi.
For a client to establish an RPC connection to an AD Lightweight Directory Services (AD/LDS) domain controller, it needs to know the name of the computer and the number of the LDAP port on which the AD/LDS domain controller is listening. First, the client establishes a connection to the endpoint mapper service on the computer.
Next the client enumerates all endpoints that are registered for the desired interface ID. Finally the client selects the endpoint whose annotation equals the LDAP port number of the desired AD/LDS domain controller.
This protocol is appropriate for the management of objects in a directory, as well as the overall management of the directory service.