1:1 NAT Forwarding/Masquerading

[anomaly0617]

Hi all,

I've done this before, but it's been years and I'm hoping someone can just give me a quick refresher on it.

I have a vendor (gotta love vendors) who has set up an internal network around their manufacturing solution wherein they are utilizing a 192.168.0.0/22, or in more human readable terms, a network where the start address is 192.168.0.0 and the end address is 192.168.3.255.

My boss wants us to connect to this network and pull stats from the manufacturing solution. There's software to do this, and we've purchased it. But the issue is that we already have networks that are on the 192.168.1.0, 192.168.2.0, and 192.168.3.0 networks. Thus, I've set up an opnsense firewall on another VLAN'ed network, which is the 192.168.20.0 network, dedicated to the various manufacturing machines.

So, my "WAN" interface on this firewall looks like this: 192.168.20.254/24
And, my "LAN" interface on this firewall looks like this: 192.168.1.254/22

I've used nmap to scan the entire network for this manufacturing solution, and I find 27 IP addresses between 192.168.0.0 and 192.168.3.255.

What I'd like to do is set up some virtual IPs on the opnSense firewall like this:

WAN 192.168.20.230 = LAN 192.168.1.10
WAN 192.168.20.231 = LAN 192.168.1.15
...

And this way we can ping and communicate with the devices on the manufacturing network using 192.168.20.x network addresses instead of their native 192.168.[0-3].x addresses.

It seems like this was possible and relatively easy once I got the hang of it. But by "getting the hang of it" I mean I did it once about 4 years ago.

Can someone refresh my memory on how to make this work?

Thanks, in advance!
Paul