Introduction to TCP client server in C#

 

Introduction

This is a simple implementation of a TCP client server relationship.

To use

Compile the server and client programs separately. Before compiling change the IP address in both programs to match that of your machine (NOTE : to get your IP address run 'ipconfig' from the command prompt in Windows NT/2000 m/c's)
When the server program is run, it will indicate at which IP it is running and the port it is listening to. Now run the client program is run , so as to establish a connection with the server.
When a connection is established the server will display the IP address and Port from where it has accepted the connection and client will ask for the string which is to be transmitted to the server.
The server on reciept of the string will display it, send an acknowledgement which will be recieved by the client.
The client can be either run from the same machine as the server or from a different machine. If run from a different machine then a network connection should exist between the machines running the server and client programs

//

/*   Server Program    */
                 
using System;
using System.Text;
using System.Net;
using System.Net.Sockets;

public class serv {
    public static void Main() {
    try {
        IPAddress ipAd = IPAddress.Parse("172.21.5.99");
         // use local m/c IP address, and 

         // use the same in the client


/* Initializes the Listener */
        TcpListener myList=new TcpListener(ipAd,8001);

/* Start Listeneting at the specified port */        
        myList.Start();
        
        Console.WriteLine("The server is running at port 8001...");    
        Console.WriteLine("The local End point is  :" + 
                          myList.LocalEndpoint );
        Console.WriteLine("Waiting for a connection.....");
        
        Socket s=myList.AcceptSocket();
        Console.WriteLine("Connection accepted from " + s.RemoteEndPoint);
        
        byte[] b=new byte[100];
        int k=s.Receive(b);
        Console.WriteLine("Recieved...");
        for (int i=0;i<k;i++)
            Console.Write(Convert.ToChar(b[i]));

        ASCIIEncoding asen=new ASCIIEncoding();
        s.Send(asen.GetBytes("The string was recieved by the server."));
        Console.WriteLine("\nSent Acknowledgement");
/* clean up */            
        s.Close();
        myList.Stop();
            
    }
    catch (Exception e) {
        Console.WriteLine("Error..... " + e.StackTrace);
    }    
    }
    
}

--------------------------------------------------------------------

/*       Client Program      */

using System;
using System.IO;
using System.Net;
using System.Text;
using System.Net.Sockets;


public class clnt {

    public static void Main() {
        
        try {
            TcpClient tcpclnt = new TcpClient();
            Console.WriteLine("Connecting.....");
            
            tcpclnt.Connect("172.21.5.99",8001);
            // use the ipaddress as in the server program

            
            Console.WriteLine("Connected");
            Console.Write("Enter the string to be transmitted : ");
            
            String str=Console.ReadLine();
            Stream stm = tcpclnt.GetStream();
                        
            ASCIIEncoding asen= new ASCIIEncoding();
            byte[] ba=asen.GetBytes(str);
            Console.WriteLine("Transmitting.....");
            
            stm.Write(ba,0,ba.Length);
            
            byte[] bb=new byte[100];
            int k=stm.Read(bb,0,100);
            
            for (int i=0;i<k;i++)
                Console.Write(Convert.ToChar(bb[i]));
            
            tcpclnt.Close();
        }
        
        catch (Exception e) {
            Console.WriteLine("Error..... " + e.StackTrace);
        }
    }

}