An NIS domain shares a common set of maps. Each domain has a domain name. Each machine belongs to a domain; machines belonging to the same domain share the same maps.
No restrictions are placed on whether a machine can belong to a given domain, as long as there is a server for that domain's maps on the same network.
Assignment to a domain is done at the local level of each machine by the system administrator logged in as the NIS administrator. See ``Setting up an NIS domain'' for instructions on how to establish the NIS domain.