#!/bin/bash
#Do a quick nmap ping sweep and create list of hosts, change ip range here:
echo -e "Generating list of live hosts, this could take a min..."
nmap -sn 10.11.1.1-254 -oG - | awk '/Up$/{print $2}' > hosts.txt

#Attempt a reverse lookup for each host:
while read host; do
#sleep 10echo -n "$host "
dig -x $host @10.11.1.220 | grep ";; ANSWER" -A1 | tail -n1 | awk 'NF>1{print $NF}'
done <hosts.txt