Cannot connect to StreamSocketListener

Question

I'm trying to connect to a StreamSocketListener in my Windows 10 app. This is working if the client socket is inside the same app. But if I try to connect from another application (e.g. Putty) it doesn't work. After a few seconds putty says "Network Error: Connection Refused".

Here is my sample code:

public sealed partial class MainPage : Page
{
    private StreamSocketListener listener;

    public MainPage()
    {
        this.InitializeComponent();

        listener = new StreamSocketListener();
        listener.ConnectionReceived += Listener_ConnectionReceived;
        listener.BindServiceNameAsync("12345").AsTask().Wait();
    }

    private async void Listener_ConnectionReceived(StreamSocketListener sender, StreamSocketListenerConnectionReceivedEventArgs args)
    {
        Debug.WriteLine("new connection");

        string message = "Hello World!";

        using (var dw = new DataWriter(args.Socket.OutputStream))
        {
            dw.WriteString(message);
            await dw.StoreAsync();
            dw.DetachStream();
        }
    }

    private async void Button_Click(object sender, RoutedEventArgs e)
    {
        // Test connection
        var serverHost = new HostName("localhost");
        var socket = new StreamSocket();

        await socket.ConnectAsync(serverHost, "12345");

        using (var dr = new DataReader(socket.InputStream))
        {
            dr.InputStreamOptions = InputStreamOptions.Partial;

            await dr.LoadAsync(12);
            var input = dr.ReadString(12);

            Debug.WriteLine("received: " + input);
        }
    }
}

In XAML i added a button to test the client connection.

In the manifest i have checked "Internet (Client)", "Internet (Client & Server)" and "Private Networks (Client & Server)".

EDIT: I'm trying to connect on the same computer. Firewall is deactivated.

Answer 1

You cannot connect to a StreamSocketListener from another app or process running in the same computer, not even with a loopback exemption. You will need to run the client in a different machine.