Tricky Networking Problem

[UberSlackr]

I have a AT&T U-verse Gateway [Router A], a D-Link DIR-655 Wireless Router [Router B], and a Netgear WNR2000v3 Wireless Router [Router C].

Both Routers B & C are connect to Router A. Router C is setup in DMZ Mode one Router A, Router B uses different address blocks in the DHCP setting. (ex Router A 192.168.1.XXX - Router B 192.168.0.XXX). Everything functions, internet works just fine.

Problem is Computers/Devices behind Router B can NOT communicate with Computers/Devices behind Router C
Nor can Computers/Devices behind Router B talk to Router C, and vice versa.

How do I make it so All devices can communication with all devices on both "networks/routers"

(and in case someone has to ask; Router B serves the house, Router C serves the Garage/Shop)

 

[john-b691]

There are likely a couple of reasons since I am not sure you have 100% fixed the NAT problem. You I suspect still have the port mapping issue going into machine in router B from the outside. You always must refer to the machines by their corresponding addresses on the WAN ports of their router A network.

First option to fix this is to convert router B and C to AP mode and let router A do all the IP.

If you want to make it work on different subnet you really need to get rid of the NAT. Many so called consumer routers are actually "gateways". They do not have the ability to just route traffic. Assuming you do have correct routers you would need to put in static routes that tell router B and router C that they need to go to the corresponding wan network ports to access the corresponding network. So in your case both router A and router C would say 192.168.0.xxx is behind 192.168.1.??? (whatever network B wan address is).