<form action="" method="post" enctype="multipart/form-data" name="form1" id="form1">
  <p>
    <label for="pod">Подсеть, вида: 12.34.56</label>
    <input type="text" name="pod" id="pod" />
  </p>
  <p>
    <input type="submit" name="send" id="send" value="Отправить" />
  </p>
</form>
<?php
$dbhost = "127.0.0.1";
$dbuser = "trinity";
$dbpass = "trinity";
$dbname = "auth";
$link = mysql_connect($dbhost,$dbuser,$dbpass) or die('Немогу соединиться с базой данных');
mysql_select_db($dbname, $link);
if (isset($_POST[pod])) {
if ($_POST[pod] !=0){
$i = 0;
WHILE($i<256) {
$query = "INSERT INTO `ip_banned` (`ip`,`bandate`,`unbandate`,`bannedby`,`banreason`) VALUES ('$_POST[pod].$i','$time','$time','Server','-1') ";
$res = mysql_query($query);
$time = time();
echo ("IP '$_POST[pod].$i Banned Sucefully<br />");
$i = $i + 1;
}
}
}
?>