php获取代理服务器真实内网IP方法

 功能：获取用户真实IP地址，代理服务器内网IP，防HTTP_CDN_FORWARDED_FOR注入

function getIP() {

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

        $realip = $_SERVER["HTTP_CDN_SRC_IP"];

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

        $realip = $_SERVER['HTTP_X_FORWARDED_FOR'];

    } elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {

        $realip = $_SERVER['HTTP_CLIENT_IP'];

    } else {

        $realip = $_SERVER['REMOTE_ADDR'];

    }

    //如果是代理服务器，有可能返回两个IP,这是取第一个即可

    if (stristr($realip, ','))

        $realip = strstr($realip, ',', true);

    return (str_replace('#', '', $realip));

}

　　

关于注入漏洞，可以查看：http://www.cnblogs.com/chengmo/archive/2013/05/29/php.html）