添加到 configuration.php

$_SERVER['REMOTE_ADDR'] = $_SERVER['HTTP_X_FORWARDED_FOR']; // 获取真实IP
list($_SERVER['REMOTE_ADDR']) = explode(', ', $_SERVER['REMOTE_ADDR'], 2); // 可能通过多个代理，其中第一个为真实ip地址
$_SERVER['HTTP_X_FORWARDED_FOR'] = $_SERVER['REMOTE_ADDR']; // 添加到WHMCS IP变量

参考：http://www.365mini.com/page/php-get-real-client-ip.htm