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）