This paper mostly expatiates tcp / ip protocol stack system as well as the data _ transmission manner on the network . it introduces program principle of socket of exploitation entironment of windows sockets network communications program : software entironment is operating system of windows 98 either windows nt because they all sustain windows sockets api 本文主要讲述了tcp ip协议堆栈的体系以及它在网络上传送数据的方式,介绍socket (套接字)的编程原理, windowssockets网络通信程序的开发环境:软件环境即为所采用的操作系统,可以是windows98 ,也可以是windowsnt ,因为它们都支持windowssocketsapi 。