Check if a port is open

.net, c#, winforms

Solution

Try this:

using(TcpClient tcpClient = new TcpClient())
{
    try {
        tcpClient.Connect("127.0.0.1", 9081);
        Console.WriteLine("Port open");
    } catch (Exception) {
        Console.WriteLine("Port closed");
    }
}

You should probably change 127.0.0.1 to something like 192.168.0.1 or whatever your router's IP address is.

Problem

I can't seem to find anything that tells me if a port in my router is open or not. Is this even possible? The code I have right now doesn't really seem to work... ``` private void ScanPort() { string hostname = "localhost"; int portno = 9081; IPAddress ipa = (IPAddress) Dns.GetHostAddresses(hostname)[0]; try { System.Net.Sockets.Socket sock = new System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Stream, System.Net.Sockets.ProtocolType.Tcp); sock.Connect(ipa, portno); if (sock.Connected == true) // Port is in use and connection is successful MessageBox.Show("Port is Closed"); sock.Close(); } catch (System.Net.Sockets.SocketException ex) { if (ex.ErrorCode == 10061) // Port is unused and could not establish connection MessageBox.Show("Port is Open!"); else MessageBox.Show(ex.Message); } } ```

Original source

Related problems