How to find IP address of router connected to another router?

I'm trying to setup two routers in my home network, and I'm confused here.

My system looks like this:

So the router 2 is connected to the line. And I'm (my PC is) connected to router 1. When I type 192.168.1.1, I connect to router 2's config page. So how can I connect to router 1's config page? I tried ipconfig in Windows' CMD, but it does not help.

So how can I find the ip of router 1 ?

Note:

192.168.1.2 says Forbidden

You don't have permission to access / on this server.

As per this thread:

You may make use of the ARP command to find the details of your router connected to another router.

1. Connect to your Access Point (or the router 1 in your diagram).
2. Open a Command Prompt.
3. Type in: arp -a

The output may look something like this:

? (192.168.1.1) at 48:f8:b3:36:1a:e8 on en0 ifscope [ethernet] ? (192.168.1.101) at 0:1b:da:29:0:7a on en0 ifscope [ethernet] ? (192.168.1.138) at a4:5e:60:e5:da:f5 on en0 ifscope permanent [ethernet] ? (192.168.1.145) at 0:90:a9:dd:a7:d9 on en0 ifscope [ethernet] ? (192.168.1.255) at (incomplete) on en0 ifscope [ethernet] ? (224.0.0.251) at 1:0:5e:0:0:fb on en0 ifscope permanent [ethernet]

You may have multiple Interfaces listed, refer to the one that matches the computer's IP address.

• I know 192.168.1.1 is my other main router (router 2 in your diagram).
• In this example, my computer is 192.168.1.138 (can be found out in several ways)
• Addresses ending with .255 can't be the access point as it's the broadcast address for that subnet.

That leaves me with two possibilities. Looking up my "DHCP client table" in my main router (router 2 in your diagram) configuration, I see 192.168.1.145 as my NAS

So by elimination, 192.168.1.101 is my other router that is acting as an access point.

You are directly connected to Router1, so the corresponding interface's of Router1 is the range of your pc's interface.

For example your pc ip address is 192.168.5.10 and it subnet mask is 255.255.255.0. So connected interface of Router1 is in range 192.168.5.1-254. Just use some tools to scan your LAN to find ip addresses used. In must cases, your pc's default gateway is Router1 IP addresses.

Edit:

Tools to scan LAN:

• Angry IP Scanner
• MyLanViewer Network/IP Scanner
• Advanced LAN Scanner

just run a traceroute (traceroute if you're on linux, tracert if windows) to an ip on the other side of router 2

From your diagram it looks like router 2 is connected to the internet, so you could type:

traceroute www.google.com

You will get output similar to this:

traceroute to www.google.co.uk (173.194.78.94), 30 hops max, 60 byte packets
 1  192.168.2.1 (192.168.5.1)  0.253 ms  0.247 ms  0.284 ms
 2  lo0-central10.pcl-ag01.blah.net (12.13.14.116)  17.208 ms  18.032 ms  18.029 ms
 3  link-b-central10.pcl-gw02.blah.net (212.159.2.162)  15.656 ms  16.099 ms  16.166 ms
4  194.core.access.blah.net (12.159.0.194)  15.654 ms  16.150 ms  16.077 ms
 5  ae2.pcl-cr01.blah.net (195.166.129.6)  16.388 ms ae1.ptw-cr02.blah.net 
95.166.129.2)  16.385 ms  16.797 ms
 6  ae1.ptw-cr01.blah.net (195.166.129.0)  17.062 ms 72.14.223.32 (172.14.223.32)  15.636 ms  15.977 ms
 7  72.14.222.97 (72.14.222.97)  15.967 ms 209.85.252.186 (209.85.252.186)  14.849 ms  15.273 ms

In this instance 192.168.5.1 is my "router 1", your router 2 should appear below this line, and may be your public ip address.