#!/usr/bin/perl -w

use strict;

print map { "$_->[0]\n" }                       # 4. pull out the name
	sort { $a->[1] cmp $b->[1] }                # 3. sort by key
		map { [$_, /[^\d.]/ ?                   # 2. make key: is it an ip or hostname?
			join '' => reverse split /\./ :     #    host -- key is reversed parts
			pack "xC4" => split /\./ ] }        #    ip -- key is packed addr
		map { chomp; s/\s*#.*$//; $_ } <>;      # 1. read in lines and strip comments