#!/usr/bin/perl -w
use strict;
use IO::Socket;

sub scan {
    my ($addr) = @_;

    $socket = IO::Socket::INET->new(
        Proto => "tcp",
        PeerAddr => $addr,
        PeerPort => 80
    ) or die $!;
        
    $socket->autoflush(1);

    print $socket "HEAD / HTTP/1.0\015\012\015\012";
    print until ($_ = <$socket>) =~ /^$/;

    close($socket);
}

my $network = "64.219.21"
my @addr = (1, 25);

@addr[0,1] = @addr[1,0] if $addr[1] < $addr[0];

scan "$network.$_" for $addr[0] .. $addr[1];