Domain Services for Windows
The minimum rights needed for a user or group to join a workstation to the domain are
Entry: Browse and Create
Additional rights that could be added are Rename and Delete if you want the user or group to have rights to rename or delete a computer object.
Assign the rights to the computers container (default location for computer objects) or to any container where the workstation objects reside. If the workstation accounts are located in a container other than the default location it is recommended only workstation accounts reside in that location. Do not mix users or other objects in the container.