Roon ARC binds to the wrong private IP [Roon on Docker]

Roon Core Machine

Docker that runs on top of TrueNas, with the following HW:
AMD 5950x
128 GB ram
4 TB NVME disk

Networking Gear & Setup Details

  1. Who is your internet service provider?

  2. Please list the make and model of your modem and router?

  3. Do you have any additional network hardware, like additional routers or managed switches?

  4. Does your network have any VPNs, proxy servers, or enterprise-grade security?

Connected Audio Devices

iPhone 12

Description of Issue -

What is the exact port forwarding error message you see in the Roon Settings → ARC tab?

In the Roon ARC tab I see the following message:

“Your Roon Core was automatically configured and has been confirmed to be securely accessible by Roon ARC.”

Under “ROON CORE IP” I see, that is the private IP associated to the Roon docker.

The funny thing is that I’ve associated a virtual network, and Roon Core runs on it (, all devices at home are able to connect to the server. But for some strange reason ARC binds to another IP, and because of this probably it is not “listening” with the correct IP, and so Roon ARC is not working.

Running Roon inside of Docker falls well outside of a typical configuration and is beyond the scope of what the Roon support team is setup to handle. There are some users running Roon in Docker and they may be able to assist with your configuration so I’ve moved this post to the #tinkering category.


It seems a bit weird that ARC tab on core tells you that everything is OK but ARC on iPhone cannot connect.

  • Is iPhone isolated from home network if you try this?
  • If not, try running ARC over cellular network. Does it work now?
  • If connected to home network, is it connected to the same virtual lan the Roon core and endpoints are connected to?
  • Is the normal Roon remote on the same iPhone working (works only when connected to home network)?

For your information and further investigation:

Roon core binds to all network interfaces, at least on my setup (my own docker image):

$ lsof -i -P -n | grep LISTEN | grep 55000
RoonAppli  38 root  139u  IPv4   27519      0t0  TCP *:55000 (LISTEN)

I have Roon container setup on host networking. My guess is that you don’t. In my situation, on an iPhone remote, the core shows up under IP address of docker host.

To investigate further, you can login to the container, install iproute2 and lsof and output some networking info:

$ apt install iproute2 lsof
[...] lots of output and asking for confirmation [...]
$ lsof -i -P -n | grep LISTEN | grep 55000 # or use the port that you set up for ARC
[...] compare output with above [...]
$ ip a
[...] lots of output abount ip adresses and interfaces [...]

This should give some idea about IP adresses and binding on ports.

Besides the above: how is your core connected to Roonlabs servers for ARC? (inbound connection on port 55000 or another one from router to Roon core on what IP address / interface?


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