There are many ways to stop the site access for an IP Address: One Example is listed below:
Code Example: Put the following code at the very top of index.php page or any required .php page <?php $bannedips = array("123.456.789.55", "987.654.321.88"); // array of blocked IP Addresses if(in_array($_SERVER['REMOTE_ADDR'], $bannedips)){ echo 'YOU ARE BANNED!'; die; } ?>