Configuring the Network Information Service (NIS)

NIS servers and clients

Three kinds of machine have NIS databases in an SCO OpenServer system: master servers, slave servers, and copy-only servers. NIS clients do not maintain an NIS database; they obtain NIS information by making requests to remote master or slave servers.

The master server updates the databases of slave and copy-only servers.

Copy-only servers, slave servers, and clients differ in the following ways:

Slave servers can satisfy requests to transfer maps if the master server becomes unavailable; copy-only servers cannot.
In a heterogeneous environment, slave servers can accept NIS requests from any client, even from those not running SCO OpenServer systems; copy-only servers cannot accept NIS requests.
Copy-only servers must poll a master server or slave server to update their maps, while slave servers' maps are updated by the master server when the master server changes its maps.
Copy-only servers only keep stripped maps and ASCII versions of NIS maps. Slave servers keep full copies of both NIS maps and their ASCII versions. Clients keep neither NIS maps nor their ASCII versions.
Clients can request NIS maps over the network; copy-only servers cannot make NIS requests but must obtain their information locally.

NOTE: NIS clients running on other than SCO OpenServer systems can make requests of SCO NIS master and slave servers.

Database changes in an NIS domain are propagated from the master server to other servers. If you create or change NIS databases on slave or copy-only servers instead of on the master server, all modifications you make are temporary and are overwritten when the master server updates them. Therefore, make all database creations and modifications on the master server machine only.