Find out active IPs in a Linux LAN
If you are on a LAN and wish to find out which computers in it currently have access to that certain LAN, you can use the following command:
for ip in $(seq 1 254); do ping -c 1 192.168.1.$ip>/dev/null; [ $? -eq 0 ] && echo “192.168.1.$ip UP” || : ; done
This will ping each computer on the 192.168.1.x subnet one time, with a one second interval between pings. The output should be something like
192.168.1.1 UP
192.168.1.17 UP
192.168.1.24 UP
…
UPDATE:
Alternatively, you can use netdiscover:
sudo apt-get install netdiscover
netdiscover -r 192.168.1.0/24
This will scan all the computers in that particular address range and present the active ones in a table that also provides a MAC address and a MAC Vendor line. Thanks go out to angelblade for this information.
Hey!! Its most easy with netdiscover
# netdiscover -r 192.168.0.0/24
Sometime ping is blocked via firewall
You could also use fping :
fping -g 192.168.1.0/24
I think is much easyer if you use nmap.
nmap -sP -n $ip
Like this you can see all the hosts even they have firewall.
How about this one (replace eth0 with your NIC):
sudo arp-scan -I eth0 -l
A minor variation:
-w1 makes it only wait 1 second.
for ip in $(seq 1 254); doping -c1 -w1 192.168.1.$ip>/dev/null && echo “192.168.1.$ip is UP”
done
sudo nmap -SP 192.168.1.0/24
try this command it will work