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SCO OpenServer networking is based on the ``client-server'' model. In its simplest form, a ``client'' is a program that requests a service and a ``server'' is a program that provides a service. In a networked environment, client programs frequently issue RPCs (Remote Procedure Calls) to request that an operation be performed; a server responds to the RPC by executing procedures to perform the operation and sending a response to the client. The terms may also refer to machines; ``server'' may refer to a host whose files or services are made available through RPCs, and ``client'' to the requesting host.
The implications of the terms ``client'' and ``server'' may vary in specific networking components. The following table summarizes some of these variations.
Examples of client-server implementations in SCO OpenServer networking components
| Component | Client | Server | 
|---|---|---|
| 
DNS
 (Domain Name Service)  | any program that queries for host names and addresses | any program that responds to queries for host information | 
| 
NFS
 (Network File System)  | any host requesting that a remote file system be mounted locally | any host that ``exports'' file systems for remote mounting | 
| 
NIS
 (Network Information Service)  | any host that requests NIS-managed information across the network | any host that fulfills requests for NIS-managed information | 
| 
SNMP
 (Simple Network Management Protocol)  | also called ``management station''; any program that queries for system status information from a remote system | also called ``agent''; any program that responds to queries from a management station | 
SCO OpenServer systems provide both client and
server administrative functionality; as servers, SCO OpenServer systems can
easily manage other machines using standard technology, while as
clients, they can be managed remotely using these technologies.