This section describes the changes, if any, that have to be made to /etc files on all NIS clients. These changes are made either by the network administrator through the file server or by the local administrator of each host. Note that the files networks(4tcp), protocols(4tcp), and services(4tcp) need not be present on any NIS clients. However, if a client will on occasion not run NIS, make sure that the above mentioned files do have valid data in them.