Salt is IPv6 oriented. I had a Salt Fiber when I was an expat in Basel for 4 years.
I received a private IPv4 address (10.12.x.x) on the public interface of the router. If that’s still the case , it will never work. There are two solutions I can think of: either you pay approx 10 CHF/month to Salt for a publicly accessible IPv4, or you define an IPv6 VPN solution that translates to IPV4 on the core and client.
What port is configured in Roon Settings → Roon ARC? The ports need to match exactly. And the IP you enter here needs to be your Core IP, which may change if you did not do an Address Reservation on it.
So - it really seems not to be supported with the current version of Salt box
I then asked about the publicly accessible IPv4 or VPN solution @Georgethesixth mentioned and he recommended to book an IPv4 … but I’m not sure if I want to pay another 10.- monthly just to use ARC. Also there’s no guarantee that it will work …
Unfortunately, as @Tobias_Imbach and several other users have already realized, Salt. Mobile SA has widely implemented IPv6 addresses for their residential accounts and uses CG-NAT for that tier. It does not appear that they have a DS-Lite IPv4 tunneling option or PCP support that will allow for Salt. users to either automatically or manually configure port forwarding. So, ARC is limited to home network use and playback of offline downloaded content at this time. Note that the team is actively researching workarounds to IPv4 port forwarding that will potentially allow for our users dead-ended with CG-NAT to access ARC on-the-go as designed. However, we don’t have a timeline or a guarantee of success for these potential future Roon-supported workarounds.
To summarize, there are three current workarounds Salt. users can take to access ARC, although they do fall within the realm of our #tinkering solutions:
1). Contact Salt. support to request a static IPv4 WAN IP address for a monthly fee. Note that, depending on the age of your Salt account, you may be able to grandfather into a static IPv4 if you originally had one reserved.