Windows NT and Solaris NIS Domains
As company networks grew and more dependence was placed on shared resources, maintaining user accounts on each computer became increasingly more cumbersome. To ease this management problem, the concept of a directory service was created. Instead of maintaining user accounts in a file on a local computer, this information was moved to directory servers that were contacted by the other computers in the network when user account information was required.
Instead of keeping user account information for all the users within a company in one place, separate name spaces are created. These name spaces are called Windows NT domains and NIS domains in Solaris software. The servers that maintain these name spaces are called domain controllers in Windows NT and NIS servers in Solaris software.
Both directory services maintain user account information on primary and backup servers. In Windows NT terminology, these are called primary domain controllers (PDCs) and backup domain controllers (BDCs). Solaris software refers to them as NIS master servers and NIS slave servers. In both cases, these servers perform the same function. Changes are always made to the PDC or NIS master, then propagated to the BDC or NIS slave. Only one PDC and one NIS master can exist in a domain, while there can be multiple BDCs and slaves. Requests from clients are serviced by either PDC/NIS masters or BDC/NIS slaves.
In Windows NT, to become a member of an existing domain, the computer name of the client must first be registered on the PDC. Solaris NIS clients do not require that their name be registered with the NIS server before becoming part of a NIS domain.
Windows NT has a notion of trusted domains, where a user in one domain can obtain some level of access rights in another domain if it is a trusted domain. Solaris NIS domains are separate entities and do not share any trust relationship. Users who need access rights in another NIS domain must have an account set up there.