UDP Port Scan problems

[jamescpp]

Hi. I have some code for doing port scans. TCP works well, UDP does not. Can anyone assist? The UDP scan code is below.

Thanks,
James

	protected String scanUDP(InetAddress IP, int port)
	{
		try{
			byte [] bytes = new byte[128];
			DatagramSocket ds = new DatagramSocket();
			DatagramPacket dp = new DatagramPacket(bytes, bytes.length, IP, port);
			ds.setSoTimeout(1000);
			ds.send(dp);
			dp = new DatagramPacket(bytes, bytes.length);
			ds.receive(dp);
			ds.close();
		}
		catch(InterruptedIOException e){
			return "CLOSED";
		}
		catch(IOException e){
			return "CLOSED";
		}
		return "OPEN";
	}

 

[jamescpp]

Anyone have any ideas here? Thanks!!!!

 

[JVZ]

Can you provide some more detail about "UDP does not." Is there an exception being thrown?

 

[jamescpp]

Sorry, you're right. No errors, just says the ports are closed, when in fact, they are open.

Thanks,
James