I’m trying to connect to my Roon server remotely using Roon ARC, but it fails to find the server connection whenever I’m outside my home network. This issue has been ongoing for at least two months now. This is between 17:30 and 18:00 hours CET (Central European Time)
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Roon ARC over 5G from my Nucleus finally works for me.
It didn’t at first, so I deleted and reinstalled the Roon ARC app on my iPhone 13 Pro Max. It still would not work and gave me the messages “Something went wrong” followed by “Poor connection.”
I finally rebooted my phone and low and behold it works now. 
Even after removing and reinstalling Roon ARC on my Android smartphone it refuses to connect to my Roon Server remotely.
The Roon server becomes remotely accessible when Tailscale VPN is active.
I’m still unable to connect to my Roon Server using Roon Arc remotely. Cloud connection is OK, Roon Server can’t be found (outside of my home network).
EDIT: Seems to be working now. A reboot of my Nucleus was required.
EDIT2: Stopped working again.
A reboot of my Roon server does not help.
UPnP does not natively support IPv6 in the same way it does for IPv4. While there is a specification called UPnP IGD v2 (Internet Gateway Device Protocol v2) that includes IPv6 support, very few routers and devices implement it fully, including UniFi gear.
Breakdown: UPnP and IPv6
| Feature | IPv4 (UPnP IGD v1) | IPv6 (UPnP IGD v2) |
|---|---|---|
| Widely supported |  Yes |
 Rarely |
| NAT traversal / port forwarding | Yes |
Not needed (no NAT) |
| Firewall rule automation | No |
In theory |
| Supported by UniFi | IPv4 only |
No IPv6 UPnP |
Why UPnP is less relevant for IPv6
- IPv6 doesn’t use NAT, so there’s no need for traditional port forwarding.
- Instead, firewall rules control access, and UPnP would need to dynamically modify those, which most routers don’t allow for security reasons.
- Security concerns have also limited adoption of UPnP for IPv6, since exposing global IPv6 addresses without strict control is risky.
What to use instead
- Manually create IPv6 firewall rules for inbound access.
- Use mDNS, SSDP, or NAT-PMP for local discovery if needed.
- For automation, some platforms (like Home Assistant) support UPnP/IGD fallback via IPv4 even in dual-stack networks.
UPnP on UniFi Cloud Gateways does not open IPv6 ports, it only applies to IPv4 port forwarding. If you want to allow inbound IPv6 traffic, you must manually create firewall rules for the specific ports and devices.
Why UPnP doesn’t apply to IPv6
- UPnP (Universal Plug and Play) is designed to automate IPv4 port forwarding through NAT.
- IPv6 doesn’t use NAT, so there’s no need for port forwarding — instead, access is controlled by firewall rules.
- UniFi’s UPnP implementation (as per Ubiquiti’s documentation help.ui.com) only manages IPv4 rules in the NAT/firewall layer.
What to do for IPv6 access
To expose a service (like Roon) over IPv6:
- Find the device’s global IPv6 address (not link-local).
- Go to UniFi Network > Firewall & Security > Internet In.
- Create a rule:
- Type: IPv6
- Direction: WAN → LAN
- Action: Accept
- Protocol: TCP
- Port: e.g. 55002
- Destination: Device’s IPv6 address
This allows direct inbound IPv6 traffic, no UPnP needed or used.
After disabling UPnP, I added an IPv4 port forwarding rule and an inbound IPv6 firewall rule manually. This resolved my connectivity issues, Roon ARC can now connect to Roon server.
RoonServer 2.56 (Build 1583) resolves my Roon ARC connectivity issues, even when the IPv6 firewall rule is absent.
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