While testing the connectivity to ROON ARC, I get the MultipleNATFound error.
I have only one Rooter/Modem in my home network, providing access to Internet as well.
I have contacted my ISP to get a static IP, but this requires to change my contract to a more expensive Business account (there is no such thing as a Static IP add-on to my existing contract).
So I would like to ask if there is a cheaper way to simulate the Static IP concept and have the ARC work.
My rooter is an AVM FritzBox! 7590.
For example, I have thought of restricting the IPs that the rooter can assign to my Roon Core (a mini-MAC actually) to only one.
Or maybe get a VPN subscription from a provider that also supplies a Static IP.
Could any of the above solve the issue? Or do you have any other suggestion?
Thank you
Describe your network setup
AVM FritzBox! 7590 Router + Fritz! Repeater 600 (I have removed the repeater from the network and the MultipleNAT issue persists)
Does the WAN side Ip address of your FRITZ!box 7590 match the 94.kkk.lll.mmm template that you see in the diagnostic text that you posted for the ‘actual_external_ip’? I.e. Does it start with ‘94.’?
If it does, then the router setup advice given by @Marin_Weigel should help.
If it does not, then, since you have already elliminated the possible source of double NAT on your own network, it is likely that your ISP is using CG-NAT and port forwarding (or port sharing) will be unable to fix the issue.
When CG-NAT isused by the ISP (and no alternative is available - such as a static ip address), then the only option (other than to change ISPs) is to use a VPN service. The one approved by Roon is Tailscale. Setup information for Tailscale can be found at:
Alternatively, some Fritz!box routers have built in support for Wireguard. This works in an identical manner to Tailscale and so, if your router supports it, then you can set it up and install the wireguard client on your mobile device and you should then have a working ARC connection (although the Roon ARC settings page will continue to report the MultipleNatFound issue).
Which sounds to me as if your router and your ISP are issuing different, contradicting IP4 addresses making it impossible for roon ARC to specifically address your server.
Is there any possibility to switch off IPv4 and use solely the roon core´s IPv6 address to open a port for this device? I remember having similar issues with my new ISP´s CGN but somehow I managed to allow only IPv6 port forwarding and that solved the problem.
Maybe you have to deactivate automatic port forwarding via Upnp and do a manual forwarding rule allowing only the correct port requesting by your roon server identifying it solely with its IPv6 ID. Just an idea.
Tailscale is a free and secure solution if you’re blocked behind CG-NAT. With a RoonServer on a MacOS, Windows, or Linux device, it’s as simple as a) installing Tailscale on your server and your phone, b) verifying that they share a single subnet, and c) connecting.
Another option is to create an end-to-end IPv6 network instead of relying on the (now pooled and dynamically assigned) WAN IPv4 address issued from your ISP, as suggested above.
