How to SSH into a computer connected to a modem while connected to a router that's bridged to that modem?

Thums

11/12/23, 6:58 AM

I have a Modem/Router (NAT) that authenticates to my ISP's fiber optic cable. This modem has one ethernet cable connected to my Computer and another to the WAN port of a Wi-Fi router.

The Router is set to Bridged mode. Connected to this router is a laptop and a server.

Both the Laptop and Server can access the Modem's configuration page (192.168.1.1) but they cannot ping the Computer (192.168.1.23) (No route to host).

The computer also cannot ping the server or the laptop.

How can I configure this setup so that all devices can reach each other? I tried port-forwarding port 22 in the Modem settings to 192.168.1.23 and then ssh'ing into 192.168.1.1. That did not work.

223

0 + 7

networking

router

nat

routing

modem

Thorsten Schöning

11/12/23, 9:18 AM

You should describe why `Computer` needs to be behind `NAT#1` at all, as that doesn't seem to make too much sense if you overall goal is that `Computer`, `Laptop` and `Server` see each other. Would be easier to physically connect them that way.

Thorsten Schöning

11/12/23, 9:25 AM

Besides that, `NAT#2` in bridge mode only knows of `NAT#1` and doesn't know that `Computer` is available there as well. That's exactly what routing is about, in your setup `NAT#1` and `Computer` would get their own subnet and you would tell `NAT#2` about that. The WAN ports purpose is to reach upstream/extern/... networks and routers are configured that way. In your case it seems you would like to have a switching setup instead, so I would expect `NAT#2` and `Computer` being connected using switching ports at `NAT#1`. This results in one network of all your devices without any routing.

Jasen

11/12/23, 10:51 AM

I can think of two completely different types of "bridge mode", and neither is suited to your application. what is the actual router configuration? what is the "modem" confuguration? (especially its LAN ports)

Thums

11/12/23, 6:52 PM

@ThorstenSchöning The "modem" is GPON. It has 2 Ethernet ports. The router has 2 LAN ports, I'm using both the ports on the router already. That's why I'm trying to use the other LAN port on the Modem. I don't think a regular domestic wifi router would have such a switching option. Can I set up this configuration if I change it from "bridged" mode to DCHP on 192.168.3.0?

Thums

11/12/23, 6:57 PM

@Jasen the router is set up in "Bridge (AP) mode". Other options are PPPoE, DHCP or Static IP. THe options on the GPON that authenticates with the ISP are very limited. It's on "route" right now, other option is "bridge". It's got DHCP enabled on 192.168.1.1

Thorsten Schöning

11/13/23, 10:18 AM

If you want a switching setup and don't have enough normal switching ports on your devices, simply by a switch and connect your devices using that. that's what they are for and aren't really that expensive. This is the easiest setup you can get, without the need to think of how non-switching LAN ports are handled by their devices for whatever reasons. Upstream WAN ports and stuff might simply not support your setup properly, things heavily depend on your concrete device, it's firmware capabilities and stuff. It's easier to avoid these problems altogether using a switch.

Thums

11/13/23, 10:07 PM

@ThorstenSchöning I agree, that's the easiest solution. I bought a cheap 5-port gigabit switch and that will be enough for my needs. Thank you for the suggestion

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: How to SSH into a computer connected to a modem while connected to a router that's bridged to that modem?

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.