PHP 获取客户端IP

function get_ip()

{

    static $realIP;

    if (isset($_SERVER)){

        if (isset($_SERVER["HTTP_X_FORWARDED_FOR"])){

            $realIP = explode(',', $_SERVER["HTTP_X_FORWARDED_FOR"]);

            $realIP = $realIP[0];

        } else if (isset($_SERVER["HTTP_CLIENT_IP"])) {

            $realIP = $_SERVER["HTTP_CLIENT_IP"];

        } else {

            $realIP = $_SERVER["REMOTE_ADDR"];

        }

    } else {

        if (getenv("HTTP_X_FORWARDED_FOR")){

            $realIP = getenv("HTTP_X_FORWARDED_FOR");

        } else if (getenv("HTTP_CLIENT_IP")) {

            $realIP = getenv("HTTP_CLIENT_IP");

        } else {

            $realIP = getenv("REMOTE_ADDR");

        }

    }

    $_SERVER['REMOTE_ADDR'] = $realIP;

    return $realIP;

}