Use interface IP address for response to incoming multicast packet

I have a multicast routing setup with forwarding on the receiving side, as follows (all Linux): +—————-+ +—————-+ +————-+ | openvpn-server |tun0 tun0| openvpn-client | forward port 53 | application | | 10.8.0.1 |============| 10.8.0.2 |——————-| 172.16.3.3 | +—————-+ +—————-+ +————-+ joined 239.1.2.3 multicast group In this set up, the openvpn-server side sends UDP packets…