Auto-blocking Server

<?php
//I recommend you run this from the command line
$bind_ip = "0.0.0.0"; //all interfaces
$bind_port = "22"; //SSH port
$server = stream_socket_server("tcp://" . $bind_ip . ":" . $bind_port, $errno, $errorMessage);

if (!$server)
{
    throw new UnexpectedValueException("Couldn't bind to socket: $errorMessage");
}

while (true)
{
    $client = @stream_socket_accept($server);

    if ($client)
    {
        $re = explode(":", stream_socket_get_name($client, true));
        $ip = $re[0];
        $string = "iptables -A INPUT -s " . $ip .  " -j DROP";
        echo $ip . " has been blocked!" . "\n";
        exec($string);
        fclose($client);
    }
}

?>