UPnP/Chromecast discovery across VLANs not working

Issue description:

I’m trying to set up a streamer on a separate IoT network in my LAN so that Symfonium can cast via UPnP to that device from a trusted network, keeping the streamer isolated from other devices but still accessible for casting.

I’m using Symfonium with a Wiim Pro streamer and a subsonic media server source. The media server along with Symfonium phone is on VLAN “Trusted”, and the Wiim Pro is in another VLAN “IoT”.

The problem I’m having is that both the android apps for Spotify and Wiim can reach the steamer across my VLANs (I have set up mDNS multicast across the networks), however Symfonium is unable to find the streamer as a UPnP device if the phone is connected to the trusted network. If I connect the phone Wi-Fi to the IoT network, then Symfonium immediately finds the streamer and can cast audio.

I’m wondering what network access Symfonium needs in order to be able to find UPnP devices that the other apps don’t seem to need? The fact that both Spotify and the WIim apps can already communicate with the streamer, but Symfonium can’t, is making me scratch my head.

Additional information:

I have temporarily enabled full network access between the VLANs to minimize any other sources of error. I also have firewall rules opening traffic to both ways between the VLANs to support mDNS multicast, along with a mDNS-repeater between the networks.


  • Spotify and Wiim apps can discover the streamer device across VLANs
  • Symfonium can not discover the streamer across VLANs
  • Symfonium can discover the streamer if connected to the same VLAN
  • Firewall rules are in place to support cross-network discovey with mDNS
  • All other traffic between the two VLANs is currently open in order to mitigate other sources of error.

Those do not use UPnP but other protocols like Spotify connect or native Wiim API.

UPnP does not use or rely on mDNS and does not work across vlan without proper proxy support on the router.

The configuration of that will depend on your router and is out of this forum support scope.