Trying to use AirVPN to port forward to machines and ports behind double-NATed ASUS router

[mafflerbach 0]

Trying to use AirVPN port forwarding to do the following. I've got a wireless T-Mobile router which will not do port forwarding or NATing. I've gotten a ASUS RT-AC68U and configured it to work with AirVPN double-natted behind the T-Mobile router. I think I have the AirVPN set up right (I get access to the internet and it shows my IP to be a Canadian AirVPN server).
What I can't figure out how to do is how/whether to configure port forwarding in AirVPN. I understand that I get the port and decide whether I want UDP or TCP or both and whether I want the same destination port or another - but there is no place to put the local LAN address of the box I want the port to have access to. Do I configure that in my Asus router? The WAN-NAT passthrough appears to be set up but I don't want to engage the virtual server or port forwarding module on the ASUS, do I?
You can see I'm a little confused and would appreciate a hand here by someone who has done it before.
 

[go558a83nk 352]

you need to use iptables to create the proper rules on the asus router. see the following post.