Listening on 0.0.0.0 does not work, cannot listen on multiple IP addresses

[xuancong84]

I use my Raspberry Pi 4 to host the UMS server. My RPI4 also hosts a VPN server (so that I can access UMS from overseas), thus it has both LAN IP and VPN server IP.

In TCP/IP programming, usually if you listen on 0.0.0.0, it will listen on all interfaces including LAN, localhost (127.0.0.1) and VPNs, but UMS does not work. Once VPN is activated, by default, UMS listens on VPN interface instead, I have to manually set LAN IP, and it does not support listening to multiple IP addresses.

Hope developer can make the improvement.