Change your router's LAN NETMASK value from 255.255.255.0 to 255.255.0.0. Now both 192.168.0.x and 192.168.1.x machines are in the LAN.
At this point you enter in the same port forward information as before. I will not know what that information is but we can fix the LAN IP range to allow your port forward to work again.
Our church's hvac system is connected online and can be reached internally at 192.168.0.200. Our building guy used to have home access to the system by entering the external IP:port, so I assume we had forwarded a port to allow external access to the hvac system. Somewhere along the way he lost home access, not sure when, maybe when we had to replace the modem or a router?
So it seems I need to port forward to that address, correct? The issue is that the linksys router is 192.168.1.1 and gives me no options to forward to the address listed below, because of the 0 instead of 1.
The connection goes:
phone line to modem (w/ built-in wifi router)
modem to hardwired firewall
firewall to unmanaged switch
Switch sends internet all over the building, including to wifi routers and directly to the hvac controls.
When connected to a wifi router (not the one built in to modem) I can access the hvac controls internally. But like I said there is no option to port forward to that address.
Total novice, hope I'm making sense, but I feel like it could be pretty simple if someone points me in the right direction. If anyone could help I'd greatly appreciate it, thanks!

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