It looks like you might be getting a CGNat connection from your ISP. I would double check with them if that is the case. And, if so, see if you can get a static ip.
My apologies for the delay in responding, things are frantic at work at the moment and I’ve had no clear air for a while. I really appreciate the follow up. I’ve taken the advice to get a static IP address, which is now active - I’ve had a few lame experiments to get it going but have not had much luck. It should be straightforward - I’m using a Mac so it’s just a case of going to system settings and following the instructions. I’ll have another go at it tomorrow. If you know of a handy resource that will assist in this I’d be grateful if you could point me towards it! I haven’t been following the forum of late so no doubt would have missed helpful posts… Again, my thanks Michael
From what we can see here, it looks like you just about have everything set up on the network and core side so that Arc should function properly. Mainly that you have UPnP active with matching IP’s from your router side and roon, which seems to be the case.
If you’re still having issues, we can still dig into setting up a manual port forwarding rule on your Telstra modem as a backup plan. That would fall under the WAN settings similar to UPnP.
Let me know if you’re still having issues getting things sorted out!