Using railgun with an ubuntu + windows 2012r2 setup

I have one bare metal server running two hyper-v instances. One instance is Windows 2012r2 and has my application+web server (using IIS). I’ve configured another instance to be ubuntu 18 (but using the 16.04 railgun code repo) and installed railgun.

my windows server runs our website through CF fine for the general public accessing it’s ip address directly or proxied through CF… the ubuntu instance is publically accessible and is listening correctly on port 2408 (according to netstat). while there’s docs on two boxes behind nat, I’m having difficulty translating that to my situation. specifically, how to I now “glue” the ubuntu railgun to the windows-based webserver?

here is a copy of my /etc/railgun/railgun.conf and /etc/railgun/railgun-nat.conf -

(it’s in screenshot form to prevent the search engines from crawling this site and caching a copy of these files for security purposes).