Running a Jellyfin server behind a gluetun container (bc IPTV). Everything works perfectly with one exception: multicast. The use case is DLNA; interoperability between the JF server and my home receiver (to listen to music).
I have the DLNA plugin installed. I also pass the FIREWALL_OUTBOUND_SUBNET variable in the docker-compose.
Gluetun docker-compose.yml is here. Relevent Jellyfin logs are here.
Anyone know how to make mDNS work?
Edit: spelling
- I can’t even get mdns to work with systemd-resolved and a local VM. - Best of luck though, definitely something I’ll be watching! 
- Have you tried adding 239.255.255.250/32 to your outbound subnets variable? This is the multicast address for SSDP which mDNS ultimately relies on if I remember right, I recall having to do this for Plex in the past. - good idea, but a slight correction - mDNS and SSDP are entirely different things, rather SSDP was Microsoft’s initial proprietary take on the idea, and mDNS was created as the new and improved standard. - mDNS does multicast (send/receive) on 224.0.0.251 and ff02::fb on port 5353, while SSDP uses 239.255.255.250 on port 1900 as you mentioned. - But I think OP’s issue is that they’re on different subnets; mDNS expects the server and the client to have a perfectly overlapping subnets inside the same LAN. If the server has 10.0.0.3/16 and 192.168.1.3/24 then the client must also have 10.0.0.7/16 and 192.168.1.7/24. Or, if you can tell the server software exactly which IPs to announce, then that might work too. - there are workarounds to this, using avahi reflector, but that thing is buggy – specifically you need to disable NSEC on the server, and lock it to either IPv4 or IPv6. - I made some note on additional pitfalls while i was writing my own mDNS and SSDP servers for fun, they’re at the bottom of this page: https://ocv.me/copyparty/helptext.html 
- I appreciate the response. I updated it and there was some success in that Jellyfin isn’t throwing errors anymore, which is a step in the right direction. So thank you for that. Unfortunately it still isn’t working. I did a little more log digging and found this: - [] [INF] [1] Jellyfin.Plugin.Dlna.Main.DlnaHost: Registering publisher for urn:schemas-upnp-org:device:MediaServer:1 on 172.21.0.2 with uri http://172.21.0.2:8096/dlna/6a8078b6-cb55-4b46-acf0-64e99f2a7a79/description.xml- I think the issue might(?) be that DLNA is on a docker subnet and my home receiver is on a local 192.169.x.x subnet. I’m not sure though. - Edit: I also checked the Jellyfin docs and tried opening up ports 1900 and 7359 on the gluetun container. That didn’t do anything though. 
 

