Use of ARC - Problem with Port Fowarding

Roon Core Machine -

Nucleus +

Networking Gear & Setup Details

Speedport Smart 3 (Telekom)

Connected Audio Devices

Project Pre Box RS2 Digital

Number of Tracks in Library

around 10,000 tracks

Description of Issue

  1. ACR is not ready in my Roon (most likely the Port Forwarding function not Set)
    If you can assist how to activate in my Speedport Router the Port Forwarding function

below the message from my Roon which I believe is a kind of standard
“connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“external_ip”: {“actual_external_ip”:“ and xxx”,“router_external_ip”:null},
“natpmp_autoconfig”: {“status”:“NotFound”},
“upnp_autoconfig”: {“status”:“NotFound”}

  1. DSP - Sample Rate Conversion:

I have set up

a) keep compatibility: (if I try to use Max. PCM - I get big distortions from my Loudspeakers… ) - Do I have any setup in my Pre Box RS2 Digital to be able to use Max. PCM?
Friends with other output device like Copland - has not problem to use.

Please give me your knowledge and/or advise

MANY Thanks for your support :slight_smile:


@Ralf_Gerhardt, the port forwarding diagnostics you’ve provided suggest that UPnP is not properly configured on your router or not working correctly.

Please try the following steps in order:

  • Reboot your Roon Core and networking gear (router, modem, switches, etc.)
  • Try to enable UPnP/NATPMP in the web administration interface for the router
  • Try to manually open the port in your router’s port forwarding configuration
  • Make sure the IP/Port matches the Port listed in Roon → Settings → ARC
  • Check for any VPNs or Firewalls that might be interfering
  • Try to update your router firmware
  • Check if your modem is in Bridgemode and if not, try to place into Bridge mode

If you continue to experience difficulties, please tag the support team and include the following information:

  1. What is the make and model of your modem and router?
  2. Do you have any additional network hardware, like additional routers or managed switches?
  3. Who is your internet service providerand what is your geographic region?
  4. Is your Modem configured in Bridge Mode so that it operates only as a modem or do you have the ports forwarded on both?

Incidentally, please create a separate thread for the other problem. Thanks.

1 Like

Hi Martin,

great - many thanks for your very fast instruction. As this process looks a little bit more sophisticated I will check in more detail over the next weekend.

After installing the Router I never was going into the Web administration interface and will need to find my way to get this done :slight_smile:

have a good day



1 Like

If you have any questions, please post here.

Hey @Ralf_Gerhardt,

You have my sincerest apologies for the delayed response here, we’ve been dealing with a higher-than-usual volume following our release and we’re working as quickly as we can to get back to everyone.

I wanted to check in to see if you were still having issues getting Arc set up? If so, please let me know. I’ll be monitoring this thread for your reply :+1:

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