I need to connect my radio over a VPN network. Do I need to use a RadioServer or a NetworkRepeater?
If the VPN can be set to forward global broadcast UDP datagrams (destination IP = 255.255.255.255) then it will work without servers.
The UDP ports to forward are 20001-20002 from the Clients to the interfaces, and ports 20010-20255 from the interfaces to the clients.