Roon ARC cannot connect (Deutsche Glasfaser, Ubiquiti Dream Machine Pro)

[jcs (jochen)]

Roon Server Machine

Synology RS818+ using Roon on DSM7

Networking Gear & Setup Details

1. Who is your internet service provider?
   Deutsche Glasfaser

2. Please list the make and model of your modem and router?
   Modem: Deutsche Glasfaser/Nokia Modem
   Router: Ubiquiti Dream Machine Pro

3. Do you have any additional network hardware, like additional routers or managed switches?
   no additional router; USW Pro 48 PoE Switch

4. Does your network have any VPNs, proxy servers, or enterprise-grade security?
   no

Connected Audio Devices

Three HomePods (AirPlay)

Description of Issue -

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

{
“ipv6_connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“ipv4_connectivity”: {“status”:“NetworkError”,“status_code”:504,“error”:“error: Error: ETIMEDOUT, response code: undefined, body: undefined connected? undefined”},
“external_ip”: {“actual_external_ip”:“94.kkk.lll.ccc”,“actual_external_ipv6”:“fde6:ddd:eee:fff:ggg:hhh:iii:jjj”,“router_external_ip”:“null”},
“natpmp_autoconfig”: {“server_ip”:“192.168.1.1”,“found_natpmp”:true},
“upnp_autoconfig”: {“server_ip”:“192.168.1.1”,“found_upnp”:true,“error”:“doaction request return statuscode: UnknownError”}
}

[connor]

Hi @jcs,

Thank you for the report. Deutsche Glasfaser has widely implemented carrier-grade network address translation (CG-NAT) for their IPv4 residential-tier account addresses.

This means traditional port forwarding won’t work, whether configured manually by port forwarding rules in your router or via the autoconfiguration tool in Roon (UPnP or NAT-PMP).

Your options here are twofold:

1. The diagnostic snippet looks like your ISP offers IPv6. You can set your network to native IPv6 from RoonServer all the way through to your upstream router. Here’s UDM’s guide on how to set DHCPv6 and native IPv6.
2. The second option is to install Tailscale (or similar) on both RoonServer and the phone. It’s a wireguard-based free VPN service that allows for peer-to-peer encrypted TCP connections over a virtual mesh network. There are threads in Tinkering Tailscale implementation with ARC to circumnavigate ISP CGNAT

We’ll stand by for your response. Thanks!

[jcs (jochen)]

Thank you, Connor. I went with the Tailscale implementation, everything working fine now. Thanks for your support!