C# Client port different from specified

Question

private void button1_Click(object sender, EventArgs e)
    {
        TcpClient joao = new TcpClient("localhost", Convert.ToInt32(25565));
        MessageBox.Show(joao.Client.LocalEndPoint.ToString());
        NetworkStream ns = joao.GetStream();
        byte[] outbytes = Encoding.ASCII.GetBytes(textBox1.Text);
        ns.Write(outbytes, 0, outbytes.Length);
        richTextBox1.AppendText("Sent : " + Encoding.ASCII.GetString(outbytes));
        ns.Close();
        joao.Close();
    }

So, this is the code i wrote for ac# client. The problem is that the output of the messageBox is "127.0.0.1:52296" and it keeps changing as i send more messages to the server. Shouldn't it be "127.0.0.1:25565" ? When i try to do it over internet it doesnt't work

Answer 1

When you initialize TcpClient with address and port, you specify the host you want to connect to: MSDN link

So your destination host's port will always be 25565, but the port the client uses to reach the host can vary (chooses randomly an available port).

Answer 2

By checking out definition of the TcpClient() overload you are using, you define the destination port as 25565 , means you connect to that remote port.

The Client object you are echoing is in reality is a Socket which has a property object called LocalEndPoint . Now that you could ask this EndPoint object about its Port .

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About why the given EndPoint.Port keeps changing:

It's sort of about how the TCP stack works, if you don't reuse that socket it will keep changing, it's normal.