Checking if port is blocked

[robUK2]

Hello,

VS 2008 SP1

I have been testing with that code.

However, I find that sometime it works and sometimes it doesn't. Very strange. I am wondering if there is a better way to do this.

I have checked this with netstat -aon (cmd). So I can check to see if the port is open.

I am not sure if it depends on the application using the port or not.

Any suggestions,

Thanks,

private bool IsPortAvailable() 
        { 
            System.Net.Sockets.Socket sock = new System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Dgram, System.Net.Sockets.ProtocolType.Udp); 
            bool available = false;  
            sock.Connect(VaxSIPUserAgentOCX.GetMyIP(), 5060); 
 
            if (sock.Connected) 
            { 
                //Port is available 
                available = true; 
            } 
            else 
            { 
                //Port is blocked 
                available = false; 
            } 
            return available; 
        }

 

[RyanEK]

Hi,

Have you tried using TCPClient? Code will raise an exception if it can't connect

TcpClient TcpScan = new TcpClient();
try
{
  TcpScan.Connect(IP, CurrPort); 
  MessageBox.Show("Port " + CurrPort + " open"); 

} 
catch 
{ 
  MessageBox.Show("Port " + CurrPort + " closed"); 
}

Ryan