NFS/NIS command. Determine version of NIS map at NIS server. yppoll asks a ypserv process for the order number and the hostname of the master NIS server for the map.
Ask the ypserv process at host about the map parameters. If host is not specified, the hostname of the NIS server for the local host (the one returned by ypwhich) is used.
Use domain instead of the default domain.