Port forwarding preventing Roon Core to ARC access

[Suedkiez (Just a fellow user like you)]

@Karsten_Thiem

MultipleNatFound

This is the problem.

There is more than one network address translation (NAT) layer active, preventing port forwarding from working although the port forwarding on the router is configured by UPnP.

As you use Vodafone Germany, they are using DS Lite for most accounts by default, which does not provide a regular public IPv4 address that can be port forwarded.

I’m copying Roon support’s standard response for the MultipleNatFound issue that most likely applies to you:

If you only have one router in your setup or your modem is already in Bridge mode, please take a look through our list of known router and internet service provider solutions, as other users may have already encountered the same situation: ISPs and Routers: List of Known Solutions and Workarounds

[Comment @suedkiez: You will find info about Vodafone Germany at the above link. This is the direct one:

Vodafone Germany: No port forwarding for home accounts. DS Lite Tunnelled IPv4 address that doesn't do port forwarding. [NOT Resolved for Most Users; See Posts. Roon Investigating]

[Edit much later: In principle this can be moved to the -resolved room, but I don’t know if Roon staff wants to clean it up, so leaving it here] The path to failure I thought I had tried everything as per the troubleshooting protocol and following the Fritzbox help pages. First with UPnP enabled, then disabled and manual setup. I always got “Not Ready” on the Roon ARC tab in Settings. This was the latest error status, then trying with UPnP again, with Independent Port Sharing enabled on the F…

In most cases it is most simply to call them and ask that they provide an external IPv4 address to your account, that can be port forwarded. This is the same thing as any online gamer with a PlayStation or similar would need. Usually the support staff will know what you are talking about. In some cases they might refuse, maybe depending on your location. In this case it should be possible to switch your regular home account to a business account, which does usually cost significantly more and includes an IPv4 address option]

You can reach out directly to your service provider to ask if they support port forwarding; this question will often enough to prompt them to explain whether or not the carrier-grade NAT they’ve implemented can function with ARC.

More specifically, you can pass along the following questions:

• Have you implemented carrier-grade NAT for my account level? [Comment @Suedkiez: in the case of Vodafone it’s not CG-NAT but probably DS Lite which amounts to the same thing]
• Have you fully implemented IPv6, or do you have IPv4 addresses available?
• Can I request a static IPv4 address to support port forwarding? [If the support people are clueless: Every online gamer needs the same thing, e.g. for a PlayStation]
• Are there any ports you have reserved at the ISP level I should be aware of?