Check if a port is open

Question

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...<

Answer 1

Other than BeginConnect you can also use ConnectAsync (added in .NET Framework 4.5 I think?).

TcpClient client = null;

try {
    client = new TcpClient();
    var task = client.ConnectAsync(host, port);
    if (task.Wait(timeout)) {//if fails within timeout, task.Wait still returns true.
        if (client.Connected) {
            // port reachable
        }
        else
            // connection refused probably
    }
    else
        // timed out
}
catch (Exception ex) {
    // connection failed
}
finally {
    client.Close();
}

Full project is here because paping refuses to run and I couldn't find another "ping host:port" tool to my likes.