To specify a server preference for:
Individual client machine, use the -L option to create a local client_info file for the machine you are running the nisprefadm on. Use the -G -C machine options to create machine-specific preferences in the global client_info table.
All machines on a subnet, use the -G -C subnetnumber option.
All machines in the current domain that do not have machine-specific or subnet-specific preferences, use the -G option.