We've run it across our MB Simulator and everything is working...
MB Sim (@ 192.168.1.131/24 GW 192.168.1.1) < -- [Modbus TCP on Port 502] -- > KepWare OPC (@ 10.0.11.123/24 GW 10.0.11.1)
Public IP: 10.0.11.139/24 GW 10.0.11.1
Private IP: 192.168.1.1/24 GW <blank>
Network Address Translation:
Public IP (Translated): 10.0.11.131
Private IP (Destination): 192.168.1.131
NOTE: Private IP (Destination) should be actual IP addresses (physical devices) in the NAT'd area with each device Gateway set to the NATR Config Private IP (192.168.1.1).
We'll get real hardware to validate against over the next few days...