《Socket Programming》.pdfVIP

Client / Server Programming with TCP/IP Sockets Author: Rajinder Yadav Date: Sept 9, 2007 Web: Email: rajinder@ Table of Content Networks 2 Diagram 1 – Communication Link 2 IPv4 Internet Protocol 2 IP Address 2 IP Classes 3 IP and the Hardware 3 IP and DNS 3 loopback 4 IP from hostname 4 hostname from IP 4 hostent structure 4 TCP Transmission Control Protocol 5 Diagram 3 – Network Hop Topology 5 TCP Window 5 Byte Ordering 6 Little-Endian 6 Big-Endian 6 Diagram 4 – Address Byte Order 6 htons( ) and htonl( ) 6 ntohs( ) and ntohl( ) 6 Sockets 6 TCP Ports 7 Table 1 – Well Known Ports 7 Opening and closing a socket 7 Initializing Winsock 7 Socket Address Structure 8 TCP Server 9 Naming the socket 9 TCP Client 12 TCP State Diagram 13 Connection Termination 13 Running The Programs 14 Network Utilities 15 ping 15 netstat 15 Server Socket Code 16 Client Socket Code 20 Rajinder Yadav Copyright © 2007 Introduction In this article we will look at how to program using sockets by implementing an echo server along with a client that we will use to send and receive string messages. I will start off by giving a quick introduction to TCP/IP fundamentals and then explain how sockets fit into the picture. I am going to assume you already understand basic network concepts. When you get done reading this article you should be armed with sufficient information to be able to investigate other concepts in more detail on your own. Sample code can be downloaded for this article from my website for anyone using VisualStudio 2008 or later. I have also included all the source code in print at the end of the article for others. Networks Most network application can be divided into two pieces: a client and a server.