How to scan devices connected to my router that isn't connected to the web?

Question

How to find the devices connected to my router via ethernet/usb that isn't connected to internet and find for example the private ip?

My situation is:

I am connected to the router via usb with my pc on which I run debian and to the same router I have connected via ethernet my raspberry. I want to ssh the raspberry from my pc but I need the private ip that I am not able to detect. I have tried to do this but doesn't work Getting all IPs of devices connected to the same router.

Any help is appreciated.

Answer 1

First note that you can SSH into a network device only from a machine that is connected to the same network as the target device. This means that if your computer is connected to your router using nothing else than a USB cable, chances are it won't work right out the box. At least it's not straightforward. Try this instead:

1. Connect your PI to a monitor using a HDMI cable and plug in a USB cable to the PI: you'll then have a text console in which you will type ip addr to retrieve the IP address of your PI

2. Make sure SSH is enabled on your PI. Only then will you be able to login remotely through SSH.

You need 1. to login remotely though. Another (guess) method is to run nmap -sP <your-computer's-network-mask> indeed and distinguish which is your raspberry PI address from there. If there's only your computer and the PI in your network, it's easy as pie (pun intended). It's more practical to go through 1. and 2. however.