I have a PC with Which must read data from a PLC device with But they are not directly connected.

The PC is connected to a 100.100.100.x LAN network which is connected to 100.100.101.x LAN network.

I have three routers to make this work. 2 edge router lite and one hirschman firewall router.

So far I can route 192.168.1.x > 100.100.100.x >100.100.101.x >192.168.2.x

But If I change my 192.168.2.x to 192.168.1.x , I can't ping the second 192.168.1.x network

I have used a PC to act as a PLC at second 192.168.1.x end

What I'm doing wrong here? Is it even possible to do this?

  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Commented Aug 14, 2017 at 18:27

1 Answer 1


You can't have the same IP range within another portion of your network unless you use Network Address Translation (NAT) to mask the addresses of both sides. This is a less than ideal solution however. Within your sphere of administrative control, at all costs keep addressing unique. That way you don't have to use NAT except at your internet edge.

You could potentially solve this with a VPN between the endpoints as well. Basically, I could solutioneer workarounds all day long, but the bottom line is this:

Without some other mechanism, and relying solely on routing, how would the routers in the middle (or the hosts on either end really) know WHICH you were wanting to reach.

  • The issue is that both the PC and the PLC can't be changed to another IP..i Guess I will have to NAT both ends to a different IP segments and use VPN to achieve this..
    – mahone_
    Commented Jul 2, 2016 at 16:13

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