I have tried enabling upnp in my Synology router, and then I also tried a port forwarded rule. I have the same external and internal port, with the same port on the core with a tcp protocol but it has made no difference
In the port forwarding settings I have also set ‘restore upnp rules on startup’ and ‘generate firewalls automatically’, again, no obvious effect.
I am using EE internet provider in the UK, via PPPoE, but I don’t think I have a static external ip.
And I am still getting the error above. Any ideas?
I expect the root cause sits with the Viper modem - it is most likely also utilising NAT (as is the Synology), thus creating rhe double NAT issue and the error you are seeing above.
This is an exact replica of the problem I had with the VirginMedia modem. In that instance I logged into the modem and changed it to ‘modem mode’ from ‘router mode’. This disabled NAT on the modem and Roon ARC connected immediately (NB: Synology just needs to have UPNP enabled, manual port forwarding rule shouldn’t be necessary)
Hopefully there is someone on the forums with experience of this modem that can help with how to change the settings
As said by others, you have to configure the Vigor in bridge mode. And after that when you want to do the portforwarding manually you have to create also a firewall rule. Without a firewall rule ARC is not going to work.
When you use upnp (and leave it on) you don’t have to use port forwarding manually. You have to leave automatically adding firewall rules on.
Explanation of the upnp process: Roon ARC is requesting a port to the router. Next the router opens a port and forward this port to Roon Core. At the same time the router creates a firewall rule so the port is open for incoming packets from internet (WAN).
If you want to do this all manually than you have to create the firewall rule manually as well as the port forwarding rule. You can disable upnp in this case.
I have set the router to bridge mode. But I am still getting the same error as originally reported. I have try UPnP and manual port forwarding. When I have the UPnP enabled I saw my NAS but not the Roon Core.
Did you restarted the modem, the Synology router and the NAS after the bridge mode enabling on the modem. Probably you have to disconnect the modem and the router from the powerline for a minute or so.