Moving from Arista - Stumped on a NGINX Issue with Device Behind OpnSense

[theprez1980]

Hey All -

I had the home version of Arista/Untangle and with the home verison being discountined decided to try to move to OpnSense.   All seems to work fine except for accessing local services hosted via NGINX redirect to another LAN device. 

All works fine when accessing the URLs via WAN - no problem there.   Attempting to use these same URLs internally behind OpnSense returns the OpnSense GUI (Yes, I've change the default port number from 443 to 8443 but no change.  It's like OpnSense is listening on 443 and simply redirecting to 8443.

Here's some more details:

I have an NGINX box behind OpnSense listening to my domain name that's updated via DDNS.   Depending on the prefix appended to the domain name - it will redirect to 443 on an given internal IP address. 

DOMAIN Name -> WAN IP -> NGINX Intercept -> Forwarding to Lan IP on Internal Port and the whole thing in reverse.

I suspect I need to poke around with reflection settings in OpnSense and checking all 3 options seems to resovle the problem but am unsure why - and if thats preferred.

Would adding NGINX to OpnSense resolve the issue - why does OpnSense not handle this like Untangle/Arista?

I think once I understand the why, I can figure out how to best address.

thanks for any input.