#!/usr/bin/perl
###################################################
# This script will parse a text file containing a
# list of IP Addresses or hostnames (one per line).
#
# Usage: mass_nslookup.pl list_of_hosts.txt
#
###################################################
use warnings;
use strict;
use Net::Nslookup;
open (FILE, $ARGV[0]);
while (<FILE>){
my $host = $_;
chomp($host);
next unless $host;
resolve_dns($host);
}
close FILE;
sub resolve_dns{
my $host = shift;
my $dns = nslookup($host);
if ($dns){
print "$host,$dns\n";
}
}