Because of how routers separate networks is it possible to say use the network 192.168.1.0/24 several times as long as you have enough networks to separate?
192.168.1.0/24 <--> 172.16.0.0/24 <--> 192.168.1.0/24
Network Engineering Stack Exchange is a question and answer site for network engineers. It only takes a minute to sign up.Sign up to join this community
Any given network that serves the public probably has a few thousand instances of 192.168.1.0/24 attached to it at any given moment, so it works. It would be somewhat insane to do so deliberately on networks managed by one company, so I'm glad to hear you wouldn't. In the case you provide where you are connecting two private networks to a third private network, there will also be some potential lack-of-joy from "double NAT" if a connection to the outside world (public IP address) is contemplated - perhaps even triple NAT depending where you connect to. Best to avoid that, IME.
After some lack of joy when setting up VPN, I have eliminated all instances of 192.168.0.0, 192.168.1.0, 192.168.2.0, 192.168.100.0, 10.0.0.0, 172.16.0.0 from any of my networks. Up until that point 192.168.1.0 was fine for many years, but having been through that, even networks I don't currently plan to connect to VPN get an address that's as non-default as I can manage, and none of them are the same. Picking a non-default section of the private address space greatly reduces issues when users are connecting from places that (nearly always) are using one of those defaults.
If you are just attempting to transit these duplicate networks, it will work. However, without NAT, or some other kludge, one duplicate network will not be able to talk to another. In your example, each router directly connected to one of the 192.168.1.0/24 networks will have a single "connected" route to 192.168.1.0/24. Neither will have a route to the far-side 192.168.1.0/24. Don't do this, it's very bad design.