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Introduction to TCP client server in C#

, 1 Oct 2001
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An article on TCP client server programming


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("");
         // 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 */        
        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);
        for (int i=0;i<k;i++)

        ASCIIEncoding asen=new ASCIIEncoding();
        s.Send(asen.GetBytes("The string was recieved by the server."));
        Console.WriteLine("\nSent Acknowledgement");
/* clean up */            
    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();
            // use the ipaddress as in the server program
            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);
            byte[] bb=new byte[100];
            int k=stm.Read(bb,0,100);
            for (int i=0;i<k;i++)
        catch (Exception e) {
            Console.WriteLine("Error..... " + e.StackTrace);




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Comments and Discussions

QuestionMultiple client support Pinmembermapartha7-Dec-14 16:20 
GeneralMy vote of 1 Pinmembermatthias Weiser19-Nov-14 2:53 
GeneralYour tutorial is excellent PinmemberMember 103515934-Sep-14 0:17 
GeneralMy vote of 5 - Good way to get started! PinmemberWilliam Ivanski3-Jul-14 18:32 
QuestionCan this Client Code Communicate to Server written in C language ?? PinmemberMember 1084085925-May-14 8:48 
AnswerRe: Can this Client Code Communicate to Server written in C language ?? PinmemberWilliam Ivanski3-Jul-14 18:34 
Questionclient-server communication Pinmemberpanqnik25-May-14 7:54 
QuestionThanks for this. PinmemberMember 1084178624-May-14 14:20 
SuggestionVery useful article PinmemberPerić Željko23-Mar-14 13:04 
Questionexcellent pedagogical presentation of the essentials Pinmembergclinkscode27-Jul-13 8:15 
QuestionI want to send a message to client which is run on different network. Can u pls help me.... Pinmembersuresh1110198317-May-13 6:09 
AnswerRe: I want to send a message to client which is run on different network. Can u pls help me.... PinprofessionalTdmonkeypoop5-Feb-14 7:49 
QuestionStill refused connection PinmemberahmedMoheb21-Apr-13 13:38 
AnswerRe: Still refused connection PinmemberTdmonkeypoop30-Jan-14 4:01 
GeneralNice one Pinmemberbilal786994-Apr-13 8:36 
GeneralMy vote of 5 Pinmemberjosemartins29-Nov-12 5:43 
Questionclient server query Pinmemberakki2309915-Nov-12 2:31 
Questionclient server query Pinmemberakki2309914-Nov-12 10:20 
QuestionUnable to read data from the transport connection: An established connection was aborted by the software in your host machine PinmemberDipakm15-Oct-12 1:35 
GeneralMy vote of 3 PinmemberMihaescu Florin14-Jul-12 0:55 
GeneralMy vote of 4 PinmemberLaxmikant_Yadav16-Feb-12 2:48 
Questionproblem Pinmembermostafa.elsadany12-Sep-11 17:56 
Generalgreetings Pinmembersamathu25-Feb-11 1:30 
GeneralNewer or updated version Pinmemberjotorres26-Aug-10 5:26 
GeneralC# Protocol Builder PinmemberHassan Assalih18-Aug-10 23:23 

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