UDP and TCP ports

Question

Hi:
I have a question. As we know, scanning TCP ports is a lot eaiser than UDP ports because active UDP ports don't respond and there are other reasons as well.
try{
Socket soc= new Scoket(address, portnumber);
catch(Throwable e){ System.out.println(e)}
look at the code above, it can only tell you active TCP ports for the Throwable e tells you nothing about UDP ports. An active UDP port doesn' respond to the connection call "soc". Therefore it will throw an exception(connection refused) after trying to connect an active UDP port. This exception is just like those of closed TCP ports.
What i am saying is that active UDP ports will be treated the same as closed TCP ports. They are hidden in closed TCP ports. How do i sift them out? Any solutions?

Answer 1

I am basically trying to determine how many UDP and TCP ports on a machine are open. Open TCP ports are easy to see. But UDP ports are tricky. Can you please tell me more in detail using a datagram socket?