Roon Arc not working, ISP done all they can

Hey @Mikael_Ohlsson,

I wanted to check in on this thread to see if you’re still having issues getting Arc up and running with your network?

Based on the error code you’ve shared, we suggest the following steps:

I’ll be on standby for your reply :pray:

Yes, I still have issues. This is the error code currently:
“connectivity”: {“status”:“NetworkError”,“status_code”:502,“error”:“error: Error: connect EHOSTUNREACH xx.xx.xx.xx:55002, response code: undefined, body: undefined”},
“external_ip”: {“actual_external_ip”:“”,“router_external_ip”:null},
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“status”:“NotFound”}

I have tried to open a port, looks like this:

The IP is the iMac where the Roon Core resides, port number corresponds to the port Roon attempts to listen to.
VPN is turned off but is installed. Firewall on the iMac is turned off. Firewall on the router is turned on, but I have tried with Firewall turned completely off.
UPnP looks like this:

Hey @Mikael_Ohlsson,

Thanks for the info. I’d be curious to know what shows when you supply 55002 there.

If it can’t, and you see "Error: I could not see your service on" something from the ISP is blocking the port as this test doesn’t involve forwarding. This site will also reveal what it sees as your public IP. If they don’t match, your ISP may very well be using CGNAT despite them saying you now have a private IP. reports the correct IP-adress, same as I got from ISP. I get this error message: Error: I could not see your service on xx.xx.xx.xx on port (55002 )
Reason: No route to host
Is there a concrete inquiry I should put to ISP? because I’am not sure what to ask them. Nevertheless I will contact them tomorrow. I’m going to work now and won’t get back before the support closes at the ISP.

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Hey @Mikael_Ohlsson,

Thank you for that information. Upon further investigation, it does appear that your ISP is using CG-Nat. You can reach out directly to your service provider to ask if they support port forwarding; this question will often enough to prompt them to explain whether or not the carrier-grade NAT they’ve implemented can function with ARC.

More specifically, you can pass along the following questions:

  • Have you implemented carrier-grade NAT for my account level?
  • Have you fully implemented IPv6, or do you have IPv4 addresses available?
  • Can I request a static IPv4 address to support port forwarding?
  • Are there any ports you have reserved at the ISP level I should be aware of?

My apologies for the run around here Mikael. Asking those specific questions to your ISP should get you setup to work with a static IP, which will connect things for you :pray:

I have a public IP-adress starting with 79.xx not 100.xx. Bahnhof states that it is a static public adress and that it should enable port forwarding, but it doesn’t. It’s not CG-NAT. They have not blocked port 55002, and they double checked that. I feel that a have triple checked this, the header still stands: “Roon Arc not working, ISP done all they can”. Is this it? Can I not use Roon Arc? According to Bahnhof is the fibre carrier planning to implement IPv6, “in a few months”. Will I have to wait for that? Is that likely to solve anything? In that case I might cancel the static IP-adress with I currently pay extra fees for

Hey @Mikael_Ohlsson,

After extensively combing through your logs, we not only found general network issues within Roons ability to reach our services but also issues between devices on your network - both remotes and endpoints dropping out.

That said, we may need to back up and bit and think of things in terms of starting at square one. Two possibilities we’re seeing from our end:

  1. This is a dual-band router, according to logs. Can you make sure that it’s not somehow switching between bands (2.4GHz vs. 5GHz)
  2. This could be DNS related or the ISP could be wrong about carrier-grade NAT. Your router shows a different external IP in logs than the one listed above here.

Let me know your thoughts :pray:

  1. I’ve disabled 5 GHz for now, wich is what I could think of to stop possible switching between bands.
  2. I haven’t explained this before but: there were some problems with the IP-adresses changing before. Turned out that ISP mapped my bought static IP to another MAC adress, so the router still used the original settings. After they corrected that, the router always shows 79.136. etc. I’ve been instructed by fellow forum users tom not divulge my static IP-adress, so it is perhaps not clear that it does not in fact change around anymore like it did when I first looked for support.
    Perhaps Bahnhof’s support doesn’t know that they uses CG-NAT, I don’t know, but I have asked three different people on three different occasion and one of them also checked with another support worker. They all deny that they do

I hear your pain and what you’re going through… I had similar issues as you did but in the end I gave up! Spent way too much time on getting this to work so instead when I am on the go, I just stream Apple Music and that’s fine. Cheers!

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After weeks and weeks of figuring this out I finally was able to use Roon Arc on the go… had a network maintenance which prevented me from using the app… I rebooted the Nucleus, did some test at home using 4G then went out and BOUM its finally working!
Lots of patience and to be honest I thought I was giving up but I persisted. Cheers!


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