Como mejoraria ustedes este anti proxy headers.

<?php
ob_start();
define('require', true);

if (isset($_SERVER['HTTP_CF_CONNECTING_IP'])) {
    $ip = $_SERVER['HTTP_CF_CONNECTING_IP'];
} else {
    $ip = $_SERVER['REMOTE_ADDR'];
}

if (isset($_SERVER['HTTP_CF_IPCOUNTRY'])) {
    $con = strtoupper($_SERVER["HTTP_CF_IPCOUNTRY"]);
} else {
    # die('Error : Cloudflare isn\'t properly configured or is not being used.');
    $error = true;
    $errcode = 0.3;
    die(); // Error
}

$proxy_headers = array(
    'HTTP_VIA',
    'VIA',
    'HTTP_X_FORWARDED_FOR',
    'HTTP_FORWARDED_FOR',
    'HTTP_X_FORWARDED',
    'HTTP_FORWARDED',
    'HTTP_CLIENT_IP',
    'HTTP_FORWARDED_FOR_IP',
    'X-PROXY-ID',
    'MT-PROXY-ID',
    'X-TINYPROXY',
    'X_FORWARDED_FOR',
    'FORWARDED_FOR',
    'X_FORWARDED',
    'FORWARDED',
    'CLIENT-IP',
    'CLIENT_IP',
    'PROXY-AGENT',
    'HTTP_X_CLUSTER_CLIENT_IP',
    'FORWARDED_FOR_IP',
    'HTTP_PROXY_CONNECTION'
);

foreach( $proxy_headers as $x ) {
    if ( isset( $_SERVER[$x] ) ) {
        if ( $x == "HTTP_X_FORWARDED_FOR" ) {
            if ( $_SERVER[$x] != $ip ) {
                die( "Proxy Detected!" );
            }
        } else {
            die( "Proxy Detected!" );
        }
    }
}
?>