dnsenum-reverse.sh

#!/bin/bash

function usage() {
    echo "Usage: "$0" <ip> <domain> [<dns_server>]"
    if [ -n "$1" ] ; then
	echo "Error: "$1"!"
    fi
    exit
}

if [ $# -lt 2 ] || [ $# -gt 3 ] ; then
    usage
fi

ip=$1
domain=$2
dnsserver=$3
n=0

for i in $(seq 0 254) ; do
	tmp=`host $ip"."$i $dnsserver | egrep $domain | cut -d ' ' -f 1,5`
	if [ -n "$tmp" ] ; then
		echo $tmp
		n=$[$n+1]
	fi
done

if [ $n -eq 0 ] ; then
	echo "Nothing found."
fi

exit