(3.0.7 - 3.0.18 only, PHP 4 >= 4.0.0)
yp_get_default_domain -- Fetches the machine's default NIS domainyp_get_default_domain() returns the default domain of the node or FALSE. Can be used as the domain parameter for successive NIS calls.
A NIS domain can be described a group of NIS maps. Every host that needs to look up information binds itself to a certain domain. Refer to the documents mentioned at the beginning for more detailed information.