udpbroadcastrelay is a UDP multicast relayer. Its intended use is to
rebroadbcast udp packets on a specific port across interfaces, be those
interfaces physical or VLAN.

It is used where devices such as Sonos or Sky are spread accross
different subnets and are not able to detect the servers or devices.

WWW: https://github.com/marjohn56/udpbroadcastrelay