ARC through SIM mobile receiver Continued

Continuing the discussion from ARC through SIM mobile receiver:

Roon Core Machine

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

Description of Issue -

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


I would like to reopen the discussion. I have asked my ISP and they don’t provide Fixed IP address anymore, at least not for SIM card.

I have a firewall device by Zyxel with VPN. Would you be able to advise if going through a VPN could allow to provide that fixed IP address, or in any other way solve the issue?

Thanks for this.


As an additional information I realise I can read a public IP on my Zyxel firewall… would it help to solve the issue?

Is there anyone from the Roon ARC support ready to help?

Hi, I am not support, but many people have circumvented CG-NAT by using a VPN, maybe you can find info here:

Many other threads if you search for VPN and ARC

Thanks. This is what I wanted to avoid using Roon ARC. I will sure try it if the setup of Roon ARC does not work.

With the firewall installed now, I have a different error message below. Can anyone help decypher?

“connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“external_ip”: {“actual_external_ip”:“”,“router_external_ip”:“null”},
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“status”:“NotFound”}

Did you set up port forwarding manually? The alternative UPnP and NAT-PMP options to autoconfigure it seem off on your router.

Though I am not sure right now if the 504 error means something else.

One thing to clarify maybe: you don’t necessarily need a fixed public IP, just a real public IP that is yours and can be port forwarded.

Mentioning this because you mentioned fixed. But public IPs that can be port forwarded come in dynamic (router gets a new one on every connection to ISP) and fixed/static (it’s always the same IP). For ARC, dynamic is fine as long as it allows port forwarding.

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Yes, I set up the port forwarding according to the explanation on the ROON site. I can try to figure out how to set up auto-config of UPnP.

It might be interesting to know what the error 504 means.

It’s fine if you have the manual rules, UPnP does not buy you anything else. I just wanted to make sure you had them.

The 504 and ETIMEOUT seems like it’s simply not getting through for other reasons. Now this sounds as if the firewall is blocking it. E.g., the same error here, and was solved by changing firewall rules:

Thanks I have three levels to check: the SIM router, the firewall, the QNAP… will do and come back

I have set the router to IP pass-through, so my standalone Firewall device should be directly accessible for ARC. On the QNAP I couldn’t find any firewall set. Remains only the firewall device, which has a port forward on the server local IP address. Still, I still get the same error.

Have I still missed anything?


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