Star out the last number set of an IP.

gistfile1.php

<?php

$ip = "10.0.11.145";

$array = explode(".", $ip);

$numbers = $array[0] . "." . $array[1] . "." . $array[2];
$numbers .= ".";

for($i = 0; $i < strlen($array[3]); $i++) {
  $numbers .= "*";
}

echo $numbers;