For example, the host.byname map consists of the hosts.byname.pag and hosts.byname.dir files. The file with the .pag extension contains the key and value pairs, while the file with the .dir extension is the index for the .pag file. The subdirectory has the same name as the domain. Maintaining Consistent System Information with NIS NIS maintains consistent system information throughout the domain by designating one system, the master server, as the sole source of information. All the other hosts, whether they are slave servers or clients, obtain their system information from the master server.
Clients obtain their information on an as-needed basis.
If the information exists, the server responds with the information. Since the client obtains the information only as needed, the system information at the client remains consistent with the server. Slave servers, on the other hand, obtain a complete copy of the maps periodically from the master server. To ensure that the system information is consistent at the slave servers, and therefore throughout the whole domain, make all updates to the maps at the master server. Then, propagate the new maps to the slave servers.