How to multithread my port scanning app?

I'm creating a small port scanning app which use a port range defined by user.

My problem with the code is that I find it not efficient enough meaning that it ping very slow, especially when ports are not responding meaning that I must wait for the timeout before continuing to next port.

I want to make this small app threaded. The problem here is that I'm kind of blank of how to implement threading in my program.

This is my code which is a method which does the actual checking, the other part of the code is a simple button with for loop for advancing my port number.

Code:

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                private void ScanPort(IPAddress address, int port)
        {
            using (TcpClient client = new TcpClient())
            {
                IAsyncResult result = client.BeginConnect(address, port, null, null);

                if (result.AsyncWaitHandle.WaitOne((int)nudTimeout.Value, false)) txtDisplay.AppendText("Port: " + port + " is open." + Environment.NewLine);
                else txtDisplay.AppendText("Port: " + port + " is closed." + Environment.NewLine);
            }
        }

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I have read some basic threading tutorial but I just don't know how to implement this piece of code so I can check ports much faster.

Hope for some advices.

Regards.

You don't need to manually create threads with Async sockets.

Quote:

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Originally Posted by theoobe

You don't need to manually create threads with Async sockets.

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Well, I'm kind of stuck at this part. I have tried to use asynchronous tcp socket connection but I couldn't figure out how to work it out of articles like this or this and my code doesn't do what I would like it to do, to check ports at least much faster speed without wait for single thread to reach the timeout.

Replace your for loop with Parallel.For