How-To Find the IP Address in used in the network (ip scanner) in Ubuntu

In ubuntu I want to find the used IP address, want to find who is use prohibited static IP address.

$sudo apt-get install nmap

Just that :) then

Here's the sample command line:-

IP Scanning with range 192.168.0.0 – 192.168.0.255
$ sudo nmap -sP 192.168.0.0/24

IP Scanning with range 192.168.0.1 – 192.168.0.254
$ sudo nmap -sP 192.168.0.1-254

Port Scanning with range port 100 – port 139
$ nmap 192.168.0.3 -p100-139

Scanning Operating system on target IP

$ sudo nmap -O 192.168.0.3

nmap Faster Execution
If you want to make faster scan, use -T4 option on nmap command..
$ sudo nmap -A -T4 192.168.0.3


reference: http://taufanlubis.wordpress.com/2007/10/20/ip-and-port-scanning-using-nmap-network-mapper-in-ubuntu/