Issue with Roon ARC connection on Synology RT2600ac with Draytek Vigor 120 in bridge mode (ref#OOBSSC)

I have a Draytek Vigor 120 in bridge mode
I have a Synology RT2600ac with upnp enabled
the core is running on an intel nuc


The port forwarding is correct and the Roon application says ARC is working but when I connect via 4g it won’t connect.

The Broadband is Plusnet fibre

also its a static IP

What’s happening?

· I'm having trouble with Roon ARC

What best describes your issue with ARC

· Other

Describe the issue

I have a Draytek Vigor 120 in bridge mode
I have a Synology RT2600ac with upnp enabled
the core is running on an intel nuc


The port forwarding is correct and the Roon application says ARC is working but when I connect via 4g it won’t connect.
The Broadband is Plusnet fibre
also its a static IP

Describe your network setup

draytek vigor 120 (bridge mode) Synology rt2600ac intel nuc core connected with cat6 cable

Hi @John_A_Leighton,

Thank you for your post. What is the specific error message you see in ARC? This will help us identify the reason for the failure. In the meantime, a few suggestions and some context.

First, I’d try a different port number than 55000 on the off-hand that other software on the network is competing. 55002 will do, or 56000. You can also try creating a manual port forwarding rule on the active upstream router, but if the port test is positive (“Ready”), it’s not likely to make the final difference here.

The Roon Settings → ARC port test will check the assigned listening port to verify that up- and downstream traffic can pass through, but it doesn’t test the phone’s own 4G/5G downstream internet connection. On one hand, this is good news - it means you’re unlikely to be behind a layer of address translation at your internet provider’s level, the most common blockage for ARC. On the other hand, it means something isn’t quite right in either a) the phone’s downstream cellular connection or b) ARC’s network ‘pathway’ to the RoonServer.

Let’s start with the first variable. Do you have any VPN’s on your phone?

If not, let’s test the second variable. Have you recently migrated RoonServer between machines, or do you have a VPN on the RoonServer machine itself? What about a second ethernet or WiFi connection that you sometimes use, or a managed switch anywhere in the network? Lastly, what about firewalls or antivirus software that can restrict or filter internet traffic to/from the machine?

In the absence of any security, network, or proxy software interfering, you can try one last heavy-handed test: reinstalling ARC on the phone.

We’ll watch for your response. Thank you!

2 Likes

Thank you @connor your solution of reinstalling the app worked, why didn’t I think of that??! Much appreciated, I am astounded by the responsiveness of the app over 4g excellent.

Hi @connor

it appears my success did not last for long. maybe I logged on over wifi last night. I tried today and it hasn’t worked.

I have changed the port to 55002

tried VPN over 4g, Roon ARC could not find server

there is no VPN on the Roon Server

there is no second ethernet or wifi

no other firewalls or antivirus.

I configured the port manually and made a manual firewall rule, didn’t work.

when I try to connect over 4g Roon ARC says “online and ready”

but when I try to connect it doesn’t

Hi @John_A_Leighton,
Thanks for writing in to let us know about this issue. Is ARC able to connect to your server when on your home Wi-Fi?

Yes it connects on the home network over wifi

Hi @John_A_Leighton,

Can you test out changing your port number, say to 55002, and see if your issue persists?

Hi @benjamin
yes tried 55002 no joy

Hi @John_A_Leighton,

The port test in Roon Settings → ARC doesn’t ping the phone through the cellular connection, it only listens for a response from the internet from the port UPnP has opened during autoconfiguration.

This indicates that, while your RoonServer machine can reach the internet through Port 55000 or 55002, ARC can’t actually sustain a connection to RoonServer via that network interface.

Usually, this occurs for one of two reasons:

  1. There are two methods of connecting to the internet on the RoonServer machine, like a VM or a simultaneous WiFi/ethernet connection. RoonServer is switching between these network interfaces, so the port test isn’t actually testing all the available pathways to ARC.

  2. Alternatively, the pathway set up by UPnP might not actually support more than a ping due to network security or traffic routing issues at level three. In other words, a firewall or VPN might be interfering, or you might need to chang settings on the Synology router.

The third possibility, although more distant, is that the cellular connection simply isn’t sufficient. Are you able to sync your ARC account to RoonServer on a WiFi connection? Under the same conditions, turn off WiFi to test.

Let’s also try setting up a manual port forward instead of using UPnP. Your Synology router will likely have an option to create a TCP port forwarding rule. Build one pointing to the IP address and listening port in Roon Settings → ARC.

We’ll keep an eye out for your post.

1 Like

Hi

I tried connecting on another mobile network (o2) with a different phone (iPhone SE) and ARC connects on 3g. So I’m guessing there must be a problem with my network (three) or my phone (iPhone 13 Pro Max). What do you think?

@connor

I tried factory resetting the phone but same problem persists.

Maybe it’s the network?

Hey @John_A_Leighton,

Thanks for following up!

We agree on this, and I’m not able to see if you tested out some of the troubleshooting steps @connor mentioned in his previous reply?

  1. Do you have more than one active network interface in your local setup? The easiest way to check this would be to access your router settings and review your devices list and each of their IP addresses. Do they all have the same first 7 (or 9) numbers? For example - 196.248.7.xx or 196.248.716.xx

Or, do you have any active VM’s within your setup?

  1. Network blockage - can you check your iPhone settings>Roon Arc and confirm that both local network and cellular data are toggled on? More likely would be a potential security setting within your router blocking the connection to Arc. One way to test bypassing this would be to create a manual port forwarding rule -

Write down the IP address and listening port number of your ROCK, you can find both these numbers under Roon Settings>Roon Arc.

Let me know if the above make sense, and if you have any questions :raised_hands:

Yes it’s very strange it doesn’t work. I have tried manual port forwarding and checked the phone application for data over mobile. I do not have any other network range apart from the standard 192.168.1. X

I do not see why my mobile network would block the service, plex works fine and connects to an open port on the router.

I do not want to change my mobile network because the service is good.

It’s a mystery to me…

Hi @John_A_Leighton ,

That is very strange behavior indeed. If you’re willing to try it out, there is a free 3rd party app that may help here called Tailscale:

this doesn’t work since the Roon Server is located on an intel Nuc not a Mac.

Hey @John_A_Leighton,

Good catch! This should be the proper link:

If you haven’t recently, I’d also remove Arc and perform a fresh download to see if your problems persist. :+1:

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