学习

<?php
if ($_SERVER['HTTP_X_FORWARDED_FOR'] === '127.0.0.1') {
    if ($_SERVER['HTTP_REFERER'] === 'www.s3Chen.com') {
        if ($_SERVER['HTTP_USER_AGENT'] === 'FXC') {
            $flag = "SACC{HTTP_1s_very_s0_ea5y!}";
            echo "flag给你，去提交吧！".$flag;
        } else {
            echo "'FXC'才是本题官方浏览器哦！" . "\n";
            echo "想要得到flag，就用官方浏览器吧！" . "\n";
        }
    } else {
        echo "好像有个网址叫做'www.s3Chen.com'，我希望你从那里过来的！" . "\n";
    }
} else {
    echo "只有本地ip地址才可以哦！" . "\n";
}