How to limit access to site

[Abraham Chaffin]

You could check the referrer using server side scripting which would be most effective or you could use javascript referrer check and than redirect.

<script>
if (document.referrer != 'https://www.creativecow.net/')
document.location='https://www.creativecow.net/';
</script>

Abraham

[Mike Smith]

Abraham’s javascript approach is a good one, if it doesn’t matter too much to you if a few people get past.

But Javascript approaches, while neat, can be easily sidestepped by users turning off javascript in the browser – and of course some users do not have javascript in their browsing device.

If you really want the page to be hidden except via one link, you’ll need to make sure you hide it from search engines so far as you can, with the robots txt approach (which is at least partly effective), and you’ll need to use e.g. .htaccess to make people log in. You might be thinking about trying to avoid cached copies as well, perhaps with a nochache approach – but as usual, absolute security is a problem, and the harder you try to reach it the more hurdles you put up for your users.

https://en.wikipedia.org/wiki/Robots_exclusion_standard
https://www.javascriptkit.com/howto/htaccess.shtml
https://www.htmlgoodies.com/beyond/reference/article.php/3472881/So-You-Dont-Want-To-Cache-Huh.htm
https://en.wikipedia.org/wiki/Referrer_spoofing