Will such a scheme (intranet) work?

Question

Computer networks

It is required to organize a small intranet using five routers (without Internet access, of course).
The following comes to mind. On the first router, set the range of IP addresses 20.0.0.0 - 20.255.255.255. On the second - 30.0.0.0 - 30.255.255.255. On the third - 40.0.0.0 - 40.255.255.255. On the fourth - 50.0.0.0 - 50.255.255.255. On the fifth - 60.0.0.0 - 60.255.255.255. Connect all five routers in series according to the LAN-to-LAN type (first to second, second to third, etc.). Will there be a common local network (i.e. our intranet) between the five routers? If you connect a third-party router to the first router, but already via LAN-to-WAN, and also, for example, another third-party router to the fifth one, also via LAN-to-WAN, then both third-party routers, it turns out, will be connected to our intranet? And the devices of the first third party router can access the devices of the second third party router through the external IP address of our intranet? For example,
That is, our five routers, which were mentioned at the beginning, act as providers. The "subscriber" represented by the first third-party router is connected to the first provider, and the "subscriber" represented by the second third-party router is connected to the fifth. At the same time, IP addresses in the range 192.168.0.0 - 192.168.255.255 are used on both third-party routers.
Is everything described correctly and will it work? If not, please correct.

Answer 1

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Answer 2

Basically, it will. It all depends on how you configure routes on routers.
If the network is small, why such huge ranges? Such half the country (I exaggerate) can be covered. And, as it were, it is customary to use 192.168.0.0 for home subnets, and 10.0.0.0 for corporate networks.
So put one subnet 192.168.0.0 and everything in it. Well, or break a bit like 192.168.1.0, 192.168.2.0 ...
So in each subnet a couple of hundred nodes will get along quite well.
Another nuance - if the connected third-party routers are under your control (i.e., you dispose of what settings will be there) - then there are (almost) no problems. But if they are administratively managed by someone else, then you need to look towards BGP, and accordingly, everything becomes much more complicated. Of course, if third-party routers are like clients, i.e. they don’t have routes somewhere else and you don’t need to have connectivity with everyone - the path will be on the same IP each, but inside they have nat with dhcp or do anything there, the main thing is to filter on your router what can go where, and what is not.

Answer 3

And just like that it is necessary that each network ash has the 8th mask? I think the 16th would be enough. Do you have more than 65 thousand hosts in one broadcast domain? What I doubt.
yes, you can at least connect 192.168.0.0/24 with 10.0.0.0/16. Routes to prescribe and that's it.
Router1 for example:
eth0 20.0.0.1/8 interface eth0
eth1 looks at router 2
Router2 for example:
eth0 30.0.0.1/8
eth1 looks at router 1
you need to do on the first router:
route add -net 30.0.0.0 netmask 255.0.0.0 gw 30.0. 0.1 eth1
On the second one: route add -net 20.0.0.0 netmask 255.0.0.0 gw 20.0.0.1 eth1
well, it's already half past twelve, and I'm not 100% sure of the answer

Answer 4

As a rule, in such networks, the 10.0.0.0/8 network is used - it is quite large. You should not borrow real IPs unnecessarily, because now you have it without access to tyrnet, and tomorrow you will need to leave and you sailed with the replacement of all these addresses of yours.