Two connected routers cannot talk to each other, yet both connect to the internet just fine

Question

So I have two routers, both running DD-WRT.

Router 1

(10.0.11.1/255.255.255.0/DHCP On) is connected to the internet via the WAN port to the ISP modem.

Router 1 also has a wireless AP connected directly to it, and a 16-port switch connected directly as well.

TV’s and such in the house are all wired to the 16-port switch, and wireless devices use either the AP, or Router 1’s build in wireless.

Router 2

(10.0.1.1/255.255.255.0/DHCP On) is connected to Router 1 using the WAN on Router 2, to an available LAN directly on Router 1.

Router 2 is in an out-building, with one PC wired to a LAN port, and whatever wireless devices are out there via Router 2’s built-in wireless.

All devices on both routers can connect outward to the internet just fine.

But I cannot for the life of me get the two routers to allow a device on Router 1 to access a device on router 2.

I have tried assigning a static IP to router 2 of 10.0.11.8 with a subnet of 255.255.255.0, setting the gateway to the address of Router 1, and setting DHCP on router 2 to forward DHCP requests, and it all goes to hell. Router 2 no longer connects to the internet, and I still can’t talk to any devices between routers.

The reason for the second router is that I had it, and it provided wireless in the outbuilding.

Any advice on how to set up the subnetting correctly?

Answer 1

Based on your setup and explanation, Router 2 is necessary only as a wireless access point and a network switch. Router 1 will manage DHCP for the entire network.

Router 1 should be connected to one of Router 2's LAN ports. In your setup, you should not be connecting anything to Router 2's WAN port.

If Router 2 doesn't support getting a local IP address via DHCP, give it an unused local IP in the same range as your LAN (e.g. 10.0.11.100) and reserve that IP on Router 1.

Now your out-building PC will become part of your LAN sharing a subnet with the other devices, and will access the internet via Router 1. Router 2 will now treat traffic from Router 1 as local traffic and not block it.