#!/usr/bin/perl -w
# FindHosts.pl by Adam Rogoyski (apoc@laker.net)
# Copyright (C) 1997 Adam Rogoyski
# usage:  ./findhosts.pl ip
# ex:    bash-2.00$ ./findhosts.pl 205.245.74.
# --- GNU General Public License Disclamer ---
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

use strict;
my ($baseip, $name, $aliases, $type, $length, $ip, $i, @addresses);
$baseip = shift || die "usage: ./findhosts.pl xxx.xxx.xxx.";
if ($baseip !~ /^\d+\.\d+\.\d+\.$/)
{
   print STDERR "usage: ./findhosts.pl xxx.xxx.xxx.\n";
   print STDERR "ex   : ./findhosts.pl 205.245.74.\n";
   exit 1;
}
$name = $aliases = $type = $length = 0;
@addresses = ();
for ($i = 1; $i <= 255; $i++)
{
   $ip = $baseip . $i;
   ($name, $aliases, $type, $length, @addresses) =
   gethostbyaddr(pack('C4', split('\.', $ip)), 2);
   if ($addresses[0])
   {
      printf "$ip $name\n";
   }
   else
   {
      print "$ip \n";
   }
}