Question

Is there a way to open an UDP port in .NET Framework without specifying port number, so the Framework finds a free port to you?

Just like Java when using:

public ServerSocket(int port),

with port = 0.

Answer 1

It works very similar to your Java example:

var udpClient = new UdpClient(0);
IPEndPoint remoteEP = null;
byte[] data = udp.Receive( ref remoteEP );

Looking at netstat it appears that a different port is allocated each time.