PURE Java™ 2

Core Networking Concepts

Java uses the protocol of the Internet, TCP/IP. In order to communicate using TCP and UDP, you must be able to identify the system you want to communicate with from your program. This system—indeed, any system in a network—is called a host, which can be either a client or server in a given application.

Note

Client and server are relative terms. A "client" for our purposes is a program or its related host calling another program (the server), which may or may not be on a different host (the server host) than the "client."

A host generally has a name. For example, I once had a system called Dagobah. Every host, however, must have an address. This address is an IP (Internet Protocol) address, consisting of four period-delimited ...