I recently ran into an issue where the clients machine had multiple NIC's with different ip addresses. One NIC was reserved for the IO/PLC/OPCUA network, and the other network was a line that went to the local network and eventually the (heavily firewalled) internet.
The question i have is while we were setting this machine up the gateway was automatically pointing to the NIC with the internet connection, i did not see anywhere to set the actual gateway NIC i wanted to use other than just the port. The correct NIC to use was the one without internet connection however it defaulted to the one with internet connection.
The only way we got it to switch over was to disable the line with the internet connection and restart the ignition service, it then selected the only available NIC.
Do you have any suggestions for this situation? thanks.
Don't use IP addresses. Use DNS names. Arrange for DNS to resolve to the production network for clients on that side of the Ignition gateway, and to resolve to the internet connection's IP address for that side. Put the DNS name into the public HTTP address setting on the gateway.
Ignition itself generally lets the machine's OS select what NIC really gets used for any particular traffic. (There are overrides in some device drivers for special cases.)