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I am wondering if there is a way I can connect to the third router in the network. The network is setup this way

PC
IP: 192.168.8.101

Router3 (home-office)
IP: 192.168.8.1
WAN IP: 192.168.3.2

Router2 (home)
IP: 192.168.3.1
WAN IP: 192.168.8.2

Router1 (isp)
IP: 192.168.8.1
WAN IP: DHCP from ISP

Router 1 is provided by ISP. This is the device they use to connect to their network. Then they provide another router and told us this is where we should connect our devices not to the first one.

Since we have 2 floors, I setup another router on the ground floor for my home-office. I want this home office to be separated from home network so I attached the cable to the WAN port and setup my home-office network.

The problem with this setup is when I need to port forward, I need to access Router1. Most of the time I am on my home-office.

My question is, how can I access web control panel of isp router (Router1) 192.168.8.1 from my PC that is connected to the home-office network?

The best I was able to do is access the second router 192.168.3.1.

Currently, I have to go up and physically attached a laptop on router1 to access its web admin panel to port forward. Wondering if I can do that from my Desktop downstairs.

Thanks

3
  • Just use a different subnet in your home office?
    – Daniel B
    Jul 10, 2017 at 8:28
  • @DanielB Can you explain further? AFAIK using different subnet will isolate me instead of connecting me to the network. My problem is how to connect to router1. Thanks
    – Wayne
    Jul 10, 2017 at 8:49
  • ? All routers are doing NAT, otherwise this wouldn’t work at all. Because the home office router is the “innermost” router, nothing cares about what internal subnet it uses. You can use anything but 192.168.3.0/24.
    – Daniel B
    Jul 10, 2017 at 8:52

2 Answers 2

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I'm assuming all these devices and their respective subnets have a /16 mask, that is; 255.255.0.0. If so, your problem is router3 and router1 have the same IP address. If all three subnets were different I think this would work out of the box. However, as it is at the moment, you are telling your PC to connect to 192.168.8.1 and as far as it knows, that is router1. The solution is to change the subnet on either router1 or router3.

[EDIT]Also, weird that your ISP would supply two routers. Don't think I've ever encountered that before.

2
  • Subnets are all 255.255.255.0. Is there a rule on the subnet number or I can just make the last digit different like I would in IP address? I agree with your comment on the ISP. I argue with them for additional power consumption but they said this is needed for the phone line to work which I don't believe because the phone line is connected to the fibre optic box. I am actually tempted to remove router2 in the picture since I was able to open the back panel of router 1 and the admin password is set to default. but for now I am trying to make it work as it is.
    – Wayne
    Jul 10, 2017 at 9:00
  • Thinking about it, I think the subnet thing is a red herring. But my point about the duplicate IP addresses stands. You'll need to change one of them.
    – Darren
    Jul 10, 2017 at 9:13
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As I understand it what you are hoping to achieve will never be possible in your current configuration.

Your problem is that Router 3 & 1 are both configured to 192.168.8.0/24

You are using your PC on Router3 connected to network 192.168.8.0/24 and you are attempting to access an IP on a separate network with the same IP range and your PC will never be able to differentiate between the two.

Your easiest solution will be to change your IP range on router 3 from a .8.0/24 to something unused elsewhere (eg 192.16.7.0/24) and then default routes should get you to 192.168.8.0/24 without any further configuration needed.

You haven't explained your topography so I can't say for definite but I assume that router3 is connected directly to router1? if so once you have changed the network on router3 it should just work.

EDIT : You wouldn't need static routes anywhere once you change the network address scheme on R3.

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  • No need for static routes. It’s all covered by the default route.
    – Daniel B
    Jul 10, 2017 at 12:29
  • Yeah, thought as much but I wasn't entirely sure what would happen if I'd got it wrong and he's daisy chanied R1->R2->R3, but I realise now that you are completely right, default routes would cover that too wouldn't it.
    – Patrick
    Jul 10, 2017 at 16:31

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