Ralf, sorry to hear about your issues in getting Roon ARC working. I moved your post to the Port Forwarding category of support. Can you please provide some additional informaiton so the Roon and the community may be able to assist you:
Who is your internet service provider?
Please list the make and model of your modem and router?
Do you have any additional network hardware, like additional routers or managed switches?
Does your network have any VPNs, proxy servers, or enterprise-grade security?
1.: my service provider is komDSL
2.: combined modem and router, manufacturter: AVM, model: Fritzbox 7490, running on latest OS
3.: yes I have a mesh consisting of the a.m. modem/router und a FritzRepeater 3000, same manufacturer, running on latest OS
add. remark: I identified the router-ext. ip adress in the testing prot. as the one that is in use for the direct IP connection to my provider. However, I was not able to identify the act. ext. ip listed in the testing protocol.
Thank you for your patience, as I understand you’ve endured a rather long wait time while we’ve worked through the queue of ARC-related issues.
Were the Fritz!Box manual port forwarding instructions @Robert_F suggested of any use in troubleshooting? If not, there’s a possibility that your provider, komDSL, has implemented IPv6 on your account level. You can pass along the following questions to their support department to illuminate their implementation:
Have you implemented carrier-grade NAT for my account level?
Have you fully implemented IPv6, or do you have IPv4 addresses available?
Can I request a static IPv4 address to support port forwarding?
Are there any ports you have reserved at the ISP level I should be aware of?