discuz中获取ip的函数

　　private function _get_client_ip() {

        $ip = $_SERVER[‘REMOTE_ADDR‘];

        if (isset($_SERVER[‘HTTP_CLIENT_IP‘]) && preg_match(‘/^([0-9]{1,3}\.){3}[0-9]{1,3}$/‘, $_SERVER[‘HTTP_CLIENT_IP‘])) {

            $ip = $_SERVER[‘HTTP_CLIENT_IP‘];

        } elseif(isset($_SERVER[‘HTTP_X_FORWARDED_FOR‘]) AND preg_match_all(‘#\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}#s‘, $_SERVER[‘HTTP_X_FORWARDED_FOR‘], $matches)) {

            foreach ($matches[0] AS $xip) {

                if (!preg_match(‘#^(10|172\.16|192\.168)\.#‘, $xip)) {

                    $ip = $xip;

                    break;

                }

            }

        }

        return $ip;

    }

但是通过 HTTP_X_FORWARDED_FOR 获取代理IP的方法有风险，客户端可以伪造：http://www.cnblogs.com/kingthy/archive/2007/11/24/970783.html