Fastest way to ping a network range and return responsive hosts?

Question

You should use NMAP:

nmap -T5 -sP 192.168.0.0-255

The following (evil) code runs more than TWICE as fast as the nmap method

for i in {1..254} ;do (ping 192.168.1.$i -c 1 -w 5  >/dev/null && echo "192.168.1.$i" &) ;done

takes around 10 seconds, where the standard nmap

nmap -sP 192.168.1.1-254

takes 25 seconds...

Try this for a unique list.

ping -c 5 -b 10.10.0.255 | grep 'bytes from' | awk '{ print $4 }' | sort | uniq

another method (fetches live hosts):

fping -ag 192.168.1.0/24

Try both of these commands and see for yourself why arp is faster:

PING:

for ip in $(seq 1 254); do ping -c 1 10.185.0.$ip > /dev/null; [ $? -eq 0 ] && echo "10.185.0.$ip UP" || : ; done

ARP:

for ip in $(seq 1 254); do arp -n 10.185.0.$ip | grep Address; [ $? -eq 0 ] && echo "10.185.0.$ip UP" || : ; done

This is python code for the ping in range of the 192.168.0.0-192.168.0.100. You can change for loop as you comfort.

# -*- coding: utf-8 -*-
import socket
import os
import sys

up_ip =[] #list to store the ip-addresses of server online
for x in range(100):  #here range is 0-100. You can change the range according to your comfort

    server_ip = '192.168.0.'+ str(x)
    print "Trying ,server_ip,... \n"

    rep = os.system('ping -c 1 ' + server_ip)

    if rep == 0:
        up_ip.append(server_ip)
        print '******************* Server Is Up **************** \n'
    else:
        print 'server is down \n'

print up_ip