Roon Arc not working, ISP done all they can

Roon Core Machine

Mac Mini Konec Roku 2012, 2,5 GHz Dual Core Intel Core i5, 16 GB 1600 MHz DDR3 RAM.

Networking Gear & Setup Details

Zyxel EX3301-TO Router on Ethernet with Wire Guard VPN turned off

Connected Audio Devices

Denon Surround Receiver connecter via TOS-LINK

Number of Tracks in Library


Description of Issue

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

ISP Bahnhof Sweden. UPnP active, UPnP NAT-T active. portchecker result: timed out

What did the ISP do “all they can” ?

They checked the settings on the router and checked that no ports is closed from their part, plus provided me with a public IP-adress.

Did you upgrade your remotes to 2.0 and upgraded the Core to 2.0?
It may require a reboot of the Core or a restart of the Core software.
Roon needs to request a port forward via uPnP or else a manual configuration of a forward is needed on your router/firewall.
Try to reboot your Core and see if the error message has changed.

It seems that you do not have an open port, and/or forwarded the correct port to your Roon Core.

You can scan your open ports through a website like this one: Open Port Checker & Scanner | Test Port Forwarding | Internet Protocol Tools

Enter your public IP address, and define a range of ports you want to scan. (I think ARC uses ports from the 55000 range).

  1. If there are no open ports, you need to open that port on your router.
  2. If there is an open port, you need to forward that specific port to the local address of your Roon core. (do make sure that the port your forward if the same that’s set in your Roon ARC settings)

Both of these settings need to be configured in your router, the Zyxel machine in your house.

Did they also make sure to check that the specific port use by Roon Arc is forwarded in your router settings? You should be able to do this yourself by googling the name of you router and “port forwarding”.

It really just is a matter of allowing an external connection over the internet to access that specific port on your Mac mini. You will find the port in question in the Roon Arc settings of your Roon Core:

Roon Arc Settings on the Roon Core:

Port Forwarding Settings on my router:

P.S. You can change the port that your Roon Core has already selected, but there really is no need to. You will need to enter this port number as both the “external” and “internal” port in your router settings, i.e. you will not be specifying a range of ports just the one you need to allow in order for Roon Arc to connect.

That doesn’t validate that the port is open on the router it needs to see a response so if your port forward is ok and roon is down it will say that the port is closed.

Yes, a reboot changed the error message:
“connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“external_ip”: {“actual_external_ip”:“xxxx”,“router_external_ip”:“100.124.XXX.XXX”},
“status”: “status”: MultipleNatFound
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“server_ip”:“”,“found_upnp”:true}

That error message is saying that you have a multiple NAT situation that needs to be resolved. See this article for the next steps:

I really don’t know exactly what they checked, sorry.
My router does not have inputs for external and internal start ports, it just says start port and end port which are both set to 55002, same as Roon. Is that the same sort of settings?

Yes, You are correct. I have done so many times now, and it just keeps reverting back to that state over and over :disappointed:

So, is your Multiple NAT situation caused by Case A or Case B? I suspect it is a Case B situation, and you’ll need to take it up with Bahnhof.

Ports 52000 to 52050 all reports as filtered (Roon listens to port 52002). I don’t quite understand how to do number 1: Open a port. When I Google I get results how to forward a port “2”, and that seems to do very little. Oh, and Roon Core is running

Stop fiddling with ports, and find out what is causing your multiple NAT situation first…

Well, they don’t seem to know what I ask for, and I really don’t know how to ask in a way that they would understand. All of this is spanking new to me. A few days ago I was vaguely aware that there are somethings called ports in a network, and now I desperately try to get a grip.

OK, seems like the thing to do. I’ll start over

Is this the only router you have in your home network? If so, then the muliple NAT situation is down to something that your ISP is doing upstream.

Second question, is the Zyxel connected to your telephone landline, or is it connected to a 3G mobile network used by Bahnhof?

I also suspect that it’s a Case B senario. The only recommendation I can find in the document is to get a Static Public IP-adress. I have got one, so I think that I need something else to try

Zyxel is the only router.
It’s a fiber optic connection. Bahnhof says that they do not perform NAT from the Optic to Ethernet modem.
Earlier I got rid of the multiple NAT error when I closed VPN, but it’s off now.
I have had four support calls to Bahnhof with four different technicians. I will try again and hopefully get one that understands my questions, that I really doesn’t understad fully myself

Are you sure you have a true static public IP4 address, and not one that is provided via CGNAT? Apparently, many Swedish ISPs use CGNAT which is a problem…