SOLVED: IPv6 is disabled on the OS but Jellyfin thinks that's not the case

[kt7brwahvw]


[2024-08-21 01:40:13.133 +00:00] [WRN] [19] Jellyfin.Networking.Manager.NetworkManager: IPv6 is disabled in Jellyfin, but enabled in the OS. This may affect how the interface is selected.



I see these messages in my log, I've told Jellyfin to disable IPv6. Jellyfin is running in a docker image with --net=host (docker inspect output):


            "Networks": {
                "host": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "755a10c5d668b5b556950d09432e1a54bb0ae7b0b3050c6cf2ca6b31f908f9f8",
                    "EndpointID": "df49755aa3773b1704ed1210b5b602eb15c1ac636a616f44ac37c97c1885d23b",
                    "Gateway": "",
                    "IPAddress": "",
                    "IPPrefixLen": 0,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "",
                    "DriverOpts": null
                }
            }



And I've confirmed on my host machine that runs the docker that there is no IPv6 interface:


docker0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 172.17.0.1  netmask 255.255.0.0  broadcast 172.17.255.255
        ether 02:42:7e:ca:aa:8c  txqueuelen 0  (Ethernet)
        RX packets 719  bytes 153740 (153.7 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1087  bytes 931818 (931.8 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

enp1s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.1.195  netmask 255.255.255.0  broadcast 192.168.1.255
        ether 00:e0:4c:24:bd:66  txqueuelen 1000  (Ethernet)
        RX packets 14672457  bytes 6797505246 (6.7 GB)
        RX errors 0  dropped 1  overruns 0  frame 0
        TX packets 14213104  bytes 6816726758 (6.8 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 433679  bytes 289539298 (289.5 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 433679  bytes 289539298 (289.5 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

vpn: flags=81<UP,POINTOPOINT,RUNNING>  mtu 1420
        inet 103.54.3.22  netmask 255.255.255.255  destination 10.5.0.2
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 1000  (UNSPEC)
        RX packets 12665070  bytes 6118818108 (6.1 GB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 11696589  bytes 2677073572 (2.6 GB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlp2s0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 54:f2:9f:3c:82:23  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0



I'm at a loss because I did see an IPv6 address connect to the machine successfully, so I really don't know what's going on:


[2024-08-20 21:53:53.911 +00:00] [WRN] [52] Emby.Server.Implementations.HttpServer.WebSocketConnection: WS "<Client IPv6 Address>" error receiving data: "The remote party closed the WebSocket connection without completing the close handshake."



My reverse proxy even terminates the SSL connection and sends things over via IPv4. Too much to paste here for my nginx config, but you'll have to trust me :)