Disabled DHCP server on secondary routers, cannot access setup page anymore on those

Question

I have the following network configuration in my home:

The Telsey DSL modem+router is provided by my ISP and setup configuration page is password protected from them (not default one, I tried brute force cracking it but the pass seems to be too long, they even charge you to activate WiFi on it).

I was initially using each of the secondary routers separately connected through the WAN port to the Telsey router. This of course gives a subset network limiting each device connected from one to the other. Since I cannot access the configuration of the Telsey router and wanted a unified network where each device can access each other in the local network I disabled the DHCP server in each secondary router and connected them via the LAN ports instead of the WAN ports. This way the Telsey router is responsible to give out IP addresses to every device in the network.

Now basically everything works as supposed, but the problem is that I cannot connect to the secondary routers so I can check/modify their configuration. Since I cannot check the specific IP address of the secondary routers from the Telsey configuration page I used an IP scanner to find them. However even though I try these addresses in a web browser they just time-out.

I believe I missed a configuration step in the secondary routers as the ASUS one reports 192.168.1.1 which is the default address. Not one that should be supplied by the Telsey router in the 192.168.2.xxx range.. If I am correct I have to reset them and set manually an IP address for these routers, right?

Also if the Telsey fails, it means the network will fail right? How do I prevent that?

Solution

You need to assign IPs to the routers first (either DHCP or static). The ASUS is inaccessible because it's on the wrong subnet. You COULD access it if you change your Windows / Linux / etc IPV4 settings to 192.168.1.1 gateway and subnet mask 255.255.255.0, with your address some static in the 192.168.1.2-254 range.

Factory reset those routers (unless you're going to sneak into the ASUS router by changing your computer's IPV4 settings), unplug them from the Telsey device, connect directly and set their IPs to come from DHCP or static in the Telsey modem's range, THEN disable the DHCP server, mate the SSIDs + PSKs, and then hook up lan-to-lan with the Telsey device (the way you have it cabled now). And it MAY be possible to prevent full network outage based on your modem's outage by connecting the two secondary routers to one another via an ethernet run. This shouldn't mess anything up because the new route will have a higher metric.

Comments

[TnF]

Btw i can reach the login page of the Telsey router at 192.168.2.1 normally.

[TnF]

Thanks man exactly what i thought it was :p The trick worked btw! I have another minor thing though: The ASUS router ip is set static to 192.168.2.100 and the TELSEY is itself to 192.168.2.1. Everything works and every device can access the TELSEY router through the ASUS and therefore get internet. However the ASUS router itself doesn't detect that it is connected to the internet, so it can't check for firmware updates/use networking tools. I've tried setting WAN on LAN1 which is the port connected to the TELSEY but it requires to make a new subnet which breaks the whole thing. What to do?

[Arthur Kay]

Does the Asus have DNS set? There may also be somewhere to give it a gateway address under where you assigned it the static IP. It's going to need both. And don't bother with WAN mode. If it has diagnostics, try to ping 8.8.8.8 vs google.com from the router.

[TnF]

Yes it does have a DNS address setting separate from the DHCP server settings. If i leave it empty and go to networking tools and google i get "ping: bad address 'www.google.com'".I happened to add a DNS address before and DNS worked although when i pinged (or just ping 8.8.8.8 manually) i get "ping: sendto: Network is unreachable". This is logical since the router expects to connect to the internet via WAN. Now WAN is set to the WAN port which isn't connected to anything, although like i said above setting WAN to LAN1 wants to make a new subnet due to ip address conflict:/

[TnF]

Ok i set it in AP mode set new static IP and it's done. Basically in router mode it expects to have a WAN by definition, but it is a little stupid if you ask me.

[Arthur Kay]

Well, you're not using it as a router, but an AP+switch so it makes sense. A router by definition connects two completely separate networks.The LAN-to-LAN cabling and DHCP turned off is a trick to use it as a switch+AP even if the software doesn't support it (older Verizon modem+routers ...) and is hit-or-miss with letting the device still have internet since its OS tends to be set to only use WAN port to talk to the internet for security reasons.