How to see the number of clients behind a router in a different subnet?

Question

linux

Hello.
I have a zuxel router, it distributes the Internet to everyone on the 192.168.0.x subnet
. And more routers are connected to it, which already distribute their own subnet to their clients.
How can I see, without having access to these routers, all their clients? Is it possible?
Thank you.

Answer 1

if these routers use NAT for access from distributed subnets outside - then no.

Answer 2

Scan the corresponding subnets, with the same nmap, for example. Provided, of course, that you have access to these subnets.