there is a sub here How to create a separate subnet for wireless access?, which shows a solution for two isolated private networks but for that you need 3 routers.
I would like to know if there is a way to achieve this same result but only using 2 routers, and how?
As I understood the above link's content, the solution with 2 routers requires the following to be solved in addition in order to achieve the 3-router's level of separation:
"2-router config works only if the ISP's main router does NOT forward requests it can't resolve to the gateway for it's own subnet (the ISP router must NOT check the WAN port for 192.168.1.2 for the two router configuration)" - "the "outer" LAN that is closer to the internet could read data coming from the "inner" LAN - 192.168.x.x IP's are non route-able for the internet, but "inner" router could let a "inner" PC access a "outer" PC via IP"
So the question is, how can I via standard Firewall/Router settings block such a behavior of "outer" & "inner" LAN interaction, or checking the WAN port for 192.168.1.2?
I know that in case of 2-router config Double NAT takes care of creating separate private networks, as stated here: https://kb.netgear.com/30186/What-is-Double-NAT. So only thing remaining is the outer/inner LAN or WAN port issue.
Reason for additional network is simply for a secure environment for IoT stuff like TV, Fridge, Heating...
