So you want to create a basic IP banning system to ban users from your site. You know their IP address and don’t want them viewing the content on your page. This code will do the trick for you!

<?php
// List all ip addresses below
$denyIP = array('192.168.1.100', '192.168.2.*', '192.168.3.10?');

$_allowed = true;

// Loop through all IP addresses
foreach($denyIP as $dip){
	$dip = str_replace('.','\.',$dip);
	$dip = str_replace('*','[0-9]{1,3}',$dip);
	$dip = str_replace('?','[0-9]{1}',$dip);
	if(ereg("^{$dip}$", $_SERVER[REMOTE_ADDR])) $_allowed = false;
}
if(!$_allowed) {
echo 'You have been banned from this site. Sorry!';
die();
}
echo $_SERVER[REMOTE_ADDR].' Approved!';
?>

In the $denyIP array, supply all the IP addresses you wish to ban. Putting a ? in the IP address will allow for any IP address with the xx? to be blocked, where xx are known and ? is unknown. You can also put a * in the IP address and block the whole range of IP addresses.

To use this script, place it at the head of all the files you wish to ban users from. Very basic, but it does the job.

Download a demo of this script that uses a database and has an admin backend: IPBan.zip