If you do not designate a naming service with fnselect, FNS uses the default naming service. The default naming service is determined by FNS based on the name service that the machine is using. If the machine is an NIS+ client, FNS uses NIS+ as the name service. If the machine is a NIS client, FNS uses NIS. If the machine is neither an NIS+ nor a NIS client, FNS uses /etc files as the machine's default name service.