Unable to stream the UDP on the internet

Solution 1:

You are not trying to just use UDP streaming (which would most likely work perfectly), you are trying to use UDP multicast streaming. This is a very important difference.

Multicast is a method, by which a single sender can talk one-way to multiple receivers. It is initiated by using special IP adresses (224.0.0.0 to 239.255.255.255), that are not normally used on the internet.

In a flat LAN this poses not many problems: The sent packets will arrive at all connected PCs via the switch and the PCs then can pick those they want and assemble the stream from them.

In a network with routers, this naive approach no longer works: It is physically impossible to transport all packets from all senders to all possible receivers, so that they can pick those that they want.

This is, why most multicast traffic doesn't cross router boundaries - only if all the routers between a receiver and a sender have a mechanism to agree on which multicast packets to transport (again: transporting all is not feasable) can they be delivered. The most common mechanism is IGMP (but others exist). I do not know any ISPs providing IGMP for their residential or SMB customers.

Absent such a mechanism, the packets for such a multicast stream will simply not arrive at your Internet connection, so no setting in your home router can make them visible.

If you control the sender, you can configure it to use unicast (i.e. "normal" UDP) to the public IP adress of your internet connection: Then your port forwards will work with a VNC stream designator of udp://@:9000.

If you do not control the sender, you can not use this sort of streaming.