Find which devices are connected to our network

Sometimes, we want to know how many devices are connected to our network. With any Unix OS you get easily know this. For this small tutorial we´re going to use Lubuntu 16.04.

We will use nmap. Nmap (Network Mapper) is a security scanner. It is used to discover hosts and services on a computer network.

For installing it, we first do

sudo apt-get install nmap

If we just need to identify the host names

 sudo nmap -sL 192.168.0.1/24

 The result of this command will be

Starting Nmap 7.01 ( https://nmap.org ) at 2016-10-02 12:39 CST
Nmap scan report for 192.168.0.0
Nmap scan report for 192.168.0.1
Nmap scan report for 192.168.0.2
Nmap scan report for 192.168.0.3
Nmap scan report for 192.168.0.4
Nmap scan report for 192.168.0.5

If we need to know the OS of the devices we have connected we do a:

sudo nmap -O 192.168.0.1/24
The address 192.188.0.1 depends of your network, you should do a ifconfig for knowing yours.

The result of this command will be something like this:

Nmap scan report for 192.168.0.8
Host is up (0.0026s latency).
Not shown: 995 closed ports
PORT     STATE SERVICE
22/tcp   open  ssh
80/tcp   open  http
3000/tcp open  ppp
3389/tcp open  ms-wbt-server
8080/tcp open  http-proxy
MAC Address: 6C:EC:EB:A5:38:5D (Texas Instruments)
Device type: general purpose
Running: Linux 2.6.X|3.X
OS CPE: cpe:/o:linux:linux_kernel:2.6 cpe:/o:linux:linux_kernel:3
OS details: Linux 2.6.32 - 3.10
Network Distance: 1 hop

 If you will like to read more about nmap, you can do a

man nmap

Thanks to this blog articles for helping me doing this small tutorial:
http://bencane.com/2013/02/25/10-nmap-commands-every-sysadmin-should-know/
https://itsfoss.com/how-to-find-what-devices-are-connected-to-network-in-ubuntu/