Question

I’m going to setup a small client/server server in TCP/IP mode, I use VS2010,C# to develop my apps, I’ve googled a lot and could find some source codes, but none of them work in internet, I can get some answers in my own local system, i.e. I run my server, then listen for my own localhost (127.0.0.1) then send some data (for example using telnet), it works fine but when I do the same over internet I get nothing! I want to use port 80, as I want to send/receive http data, I have tested several source codes, here is the last code I have used (and it works on localhost with telnet)

//server code:

form_load()
    IPAddress localAddress = IPAddress.Parse("127.0.0.1");
                Socket listenSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPEndPoint ipEndpoint = new IPEndPoint(localAddress, 80);

            // Bind the socket to the end point
            listenSocket.Bind(ipEndpoint);

            // Start listening, only allow 1 connection to queue at the same time
            listenSocket.Listen(1);
            listenSocket.BeginAccept(new AsyncCallback(ReceiveCallback), listenSocket);
            Console.WriteLine("Server is waiting on socket {0}", listenSocket.LocalEndPoint);

            // Start being important while the world rotates
            while (true)
            {
                 Console.WriteLine("Busy Waiting....");
                Thread.Sleep(2000);
            }

        public static void ReceiveCallback(IAsyncResult AsyncCall)
    {
         System.Text.ASCIIEncoding encoding = new System.Text.ASCIIEncoding();
        Byte[] message = encoding.GetBytes("I am a little busy, come back later!");

        Socket listener = (Socket)AsyncCall.AsyncState;
        Socket client = listener.EndAccept(AsyncCall);

        Console.WriteLine("Received Connection from {0}", client.RemoteEndPoint);
        client.Send(message);

        Console.WriteLine("Ending the connection");
        client.Close();
        listener.BeginAccept(new AsyncCallback(ReceiveCallback), listener);
    }

send data (client), of course I haven’t used this code, is it right?

        public static string SendData()
    {
        TcpClient client = new TcpClient();
        client.Connect(IP, 80);
        StreamWriter sw = new StreamWriter(client.GetStream());
        StreamReader sr = new StreamReader(client.GetStream());

        //if statement evalutes to see if the user has selected to update the server
        //" " = update server
        //"" = do not update the server
        //if (updateData.Equals(""))
        //{
        //    space = "";
        //}
        //else if (!updateData.Equals(""))
        //{
        //    space = " ";
        //}
        //Refrences stream writer, username variable passed in from GUI
        //space variable provides update function: "" = dont update. " " = update database.
        sw.WriteLine("h");
        sw.Flush();
        //data send back from the server assigned to string variable 
        //string recieved = sr.ReadLine();
        return "";

    }

I’m going to have the server code in my Server (winserver 2008R2) but currently test it in normal PCs, what am I doing wrong? I want to send some http packet from a random system (with a random IP) to my server (which I know its IP), what should I do? is it possible with tcp/ip or I should do something else?
is it related to static IP? should I certainly have static IP? my web server has a static IP but my clients do not, is it a problem?
I think I have some problem in defining ports and IPs, how should I set them? my server has a specific IP, but I don’t know IP of my clients, would you please explain it to me step by step?
thanks

Answer 1

The two most common problems in this scenario:

1. Ensure your server’s router is using port forwarding to forward HTTP requests from the router to the server.
2. Ensure you are connecting to the server’s public IP address, not its local network address.