Hello everyone, I am having some issues with a pretty particular situation. I am pretty new to advanced networking so there might be some obvious things I might be missing, so the more details/corrections you can give me, the better.
I have currently set up DDNS to be able to remote into some of my physical machines on my home network. It works very well, without issues and I am monitoring my ports for any suspicious activity with a packet logger. The thing is, I have a friend to whom I want to give access to some of my computational resources, but I don't want to give out the DDNS:ports associated to any physical machines, so instead I decided to make a Windows 10 VM to which I give certain computational resources and place that VM behind a virtual OpnSense modem which is also a VM.
So far, I managed to get the OpnSense VM up and running and managed to get the Windows 10 VM connected on the LAN side of the OpnSense virtual modem to connect to the internet without issue. I also set up the DDNS client on the OpnSense virtual modem with a different DDNS domain from the one on my physical modem. From online guides and other sources, I was told to set up port forwarding the following way: on the GigaHub4000 set an external port X to point to internal port X on the OpnSense virtual modem, on the OpnSense virtual modem set external port X to point to port 3389 on the Windows VM. I did all that, but I can't connect to it. The android App gives me error 0x104 and on the Windows VM, using the built-in Windows 10 troubleshooter on the network adapter produced an output saying that the issue was that there was multiple devices doing NAT (double NAT basically).
I tried to search for solutions, and one source said to place the OpnSense virtual modem in the Advanced DMZ of the GigaHub4000, BUT I remember reading somewhere in some Bell manual that using the Advanced DMZ would disable DDNS for devices on it aka I would not be able to remote into my physical devices using my original DDNS domain. The other solution was to put the GigaHub4000 in bridged mode, but that is not an option since I DO NOT want to put all my devices behind the virtual OpnSense modem.
What is my next best move here? Someone suggested making a VPN to connect to the LAN side of the OpnSense modem, would that work or will there still be double NAT issues? I have no experience making home-pointing VPNs so I would not know. Is there a way to place the OpnSense virtual modem in the GigaHub's Advanced DMZ and also retain DDNS access to my physical devices? Any help would be greatly appreciated!
