R9000 - OpenVPN Client + Port Forwarding Doesn't work and it's OK

Hi guys,

Discovered something yesterday so putting it on here in case someone else is wondering why they can't port forward whilst the openvpn client is running.

Scenario: I've got a NAS that I used to connect to from the outside world. The NAS is capable of running it's on VPN server so the direct connection was always safe. This worked well and the setup was - internet -> NO IP DDNS -> ISP modem (port forwarded to R9000) -> R9000 (port forwarded to NAS) -> NAS

Now, this fails completely the moment I've got OpenVPN client running on the router and it is connected to the VPN. After much review, reading, and testing, this is AS PER DESIGN.

The only way port forwarding will work in a sceanrio where it's something like: internet -> NO IP DDNS -> VPN (ISP Modem -> R9000 -> NAS) is when the VPN service allows you to configure port forwarding. ExpressVPN doesn't where as PIA does (a single port). 

After having read a fair few articles and spent hours on this topic, I'm actually ok with no forwarding since it's more secure and that's more important to me. My workaround is using ElephantDrive web/app which I was going to anyway since I backup my NAS to ElephantDrive.

I'm no networking expert and know little of the underlying technicals but in laymans terms the above is what I discovered. If you think it's incorrect and that port forwarding is actually just as secure and can actually be done with ExpressVPN I'd love to hear about it.

Cheers