Question

I have a typical server in my end and a friend using a client to connect to my IP/Port and he consistently receives the exception: “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 {MY_IP}:{MY_PORT}”—You don’t need to know my IP.

The client and server, however, work fine on the loopback address (127.0.0.1). I also do not have any firewall nor is windows firewall active.

Server:

static void Main(string[] args)
        {
            Console.Title = "Socket Server";
            Console.WriteLine("Listening for messages...");

        Socket serverSock = new Socket(
            AddressFamily.InterNetwork,
            SocketType.Stream,
            ProtocolType.Tcp);

        IPAddress serverIP = IPAddress.Any;
        IPEndPoint serverEP = new IPEndPoint(serverIP, 33367);

        SocketPermission perm = new SocketPermission(NetworkAccess.Accept, TransportType.Tcp, "98.112.235.18", 33367);
        serverSock.Bind(serverEP);
        serverSock.Listen(10);

        while (true)
        {
            Socket connection = serverSock.Accept();

            Byte[] serverBuffer = new Byte[8];
            String message = String.Empty;

            while (connection.Available > 0)
            {
                int bytes = connection.Receive(
                    serverBuffer,
                    serverBuffer.Length,
                    0);

                message += Encoding.UTF8.GetString(
                    serverBuffer,
                    0,
                    bytes);
            }

            Console.WriteLine(message);
            connection.Close();
        }
    }

Client:

static void Main(string[] args)
    {
        // Design the client a bit
        Console.Title = "Socket Client";

        Console.Write("Enter the IP of the server: ");
        IPAddress clientIP = IPAddress.Parse(Console.ReadLine());
        String message = String.Empty;

        while (true)
        {
            Console.Write("Enter the message to send: ");
            // The messsage to send
            message = Console.ReadLine();

            IPEndPoint clientEP = new IPEndPoint(clientIP, 33367);

            // Setup the socket
            Socket clientSock = new Socket(
                AddressFamily.InterNetwork,
                SocketType.Stream,
                ProtocolType.Tcp);

            // Attempt to establish a connection to the server
            Console.Write("Establishing connection to the server... ");
            try
            {
                clientSock.Connect(clientEP);

                // Send the message
                clientSock.Send(Encoding.UTF8.GetBytes(message));
                clientSock.Shutdown(SocketShutdown.Both);
                clientSock.Close();
                Console.Write("Message sent successfully.\n\n");
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }
    }

Answer 1

Looks like it was an error on the client side with some firewall.