The Client-Server Model
It may be rather like stating the obvious, but we define the terms server and client. A server is a network node that makes compute or data resources available. A client is a network node that utilizes server resources. Of course, for clients and servers to interact, they must be interconnected.
Nodes may act in one, both, or neither capacity of server and client. Generally speaking, from the Linux perspective, the client is the system upon which a command invoking a network-based application is executed. The server is the system on which a daemon is running. A daemon is a special program that responds to and handles resource requests. Throughout this book we will deal with, and further refine, these terms.