Question

I am trying to write a basic app that will read data off a port. Here is my code:

static void Main(string[] args)
{
    int port = 5600;
    string server = "MyDevLaptopName";
    TcpClient tcpClient = new TcpClient();
    tcpClient.Connect(server, port);

    NetworkStream stream = tcpClient.GetStream();
    byte[] data = new byte[256];
    stream.Read(data, 0, data.Length);

    Console.ReadLine();
}

When I run the app above I get this error on the tcpClient.Connect command:

A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 10.90.91.19:5600

I am not sure why my computer will not respond (I am totally new to TCP ports and such).

Is there a different way I need set this up to read data from a TCP port?

Things I have checked:

• Windows Firewall is completely off.
• The IP address listed in the error is the internal IP address of my development machine (the machine I am trying to connect to).
• I do have Symantec Endpoint Protection, but it is controlled by Group Policy and it would be difficult for me to get turned off (but I can do it if need be).

Update:
There is a main frame server that is supposed to be sending TCP data to that port. I do not control that machine/server or the method that it sends the data. I am just trying to read the data that is sent to the port.

Update II:
The main frame is actually sending the data to a VM at my company. I then use the technique found here to redirect that TCP traffic to the same port on my machine (where I hoped I could just read it off).

Update III:
The mainframe is the client and I need to be the server!. Once I realized that I got things working.

Answer 1

I would try with another port number, are you in control of the server as well? if so try to follow these steps:

C# Tutorial – Simple Threaded TCP Server

as you will see there you can listen in this way:

namespace TCPServerTutorial
{
  class Server
  {
    private TcpListener tcpListener;
    private Thread listenThread;

    public Server()
    {
      this.tcpListener = new TcpListener(IPAddress.Any, 3000);
      this.listenThread = new Thread(new ThreadStart(ListenForClients));
      this.listenThread.Start();
    }
  }
}

and you can connect in this way:

TcpClient client = new TcpClient();

IPEndPoint serverEndPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 3000);

client.Connect(serverEndPoint);

NetworkStream clientStream = client.GetStream();

ASCIIEncoding encoder = new ASCIIEncoding();
byte[] buffer = encoder.GetBytes("Hello Server!");

clientStream.Write(buffer, 0 , buffer.Length);
clientStream.Flush();

it seems trivial and it is, but port number is not a detail as some ports are not available or blocked by firewalls or so…