How to find all the used IP addresses by Ubuntu systems on a network?

Question

What command can I use to get a list of IP addresses used by Ubuntu systems in LAN network?

Answer 1

You can use nmap to get a list of ip's that are up:

nmap -sP 10.10.10.0/24

To find out if they are Ubuntu systems is harder. You can use a portscan (-sS, -sT or -sF for instance) and the -O option.

This does require you to have admin privileges, so you'd do something like

sudo nmap -sT -O  10.10.10.0/24

For ranges (the 0/24 part) and the options, you can check out the manpage of nmap.

Answer 2

Try nmap -sP -A 192.168.1.1/24.