I just want to find out unused IP Address on a network. I think it is possible with nmap. Can any one say me the way pls?
Note:
I just need the free IP list alone.
A fast scanner is arp-scan which uses ARP to "see" other machines on a network. It also returns the MAC address and tries to determine the manufacturer of the network adapter.
Example usage (replace wlan0 by eth0 if needed):
$ sudo arp-scan -I wlan0 192.168.1.0/24
Interface: wlan0, datalink type: EN10MB (Ethernet)
Starting arp-scan 1.6 with 256 hosts (http://www.nta-monitor.com/tools/arp-scan/)
192.168.1.10 00:90:f5:33:e2:f2 CLEVO CO.
192.168.1.254 00:14:7f:72:cd:05 Thomson Telecom Belgium
2 packets received by filter, 0 packets dropped by kernel
Ending arp-scan 1.6: 256 hosts scanned in 1.406 seconds (182.08 hosts/sec). 2 responded
Note that this utility only reports machines which are powered on. ping can be blocked, but arp-scan cannot be blocked since it's necessary for a machine to interact with other machines on a network. To be sure that an IP is unused, you'd better look at your router (for static/dynamic addresses) and DHCP server (for dynamic addresses).
