I have looked around, and haven't found any questions regarding what I need.
I would like to make something like an "admin.php", but I would like to make it where it returns a 404 if the conditions aren't right. However, a 404 that looks different from all the rest of the 404 pages will hint to the attacker that "admin.php" is a real file.
I don't want to make my own custom 404 page, I think Apache's default 404 is good enough for me. How do I send a 404 that triggers apache to send the already ErrorDocument. I assume this error document, after searching for it, is located (in Ubuntu): "/usr/share/apache2/error/HTTP_NOT_FOUND.html.var"
When I use things like:
<?php
http_response_code(404);
die();
?>
it looks like this in the web browser:
When I request a URL that truly isn't on the web server it looks like this:
I would like to know how I could make the "/admin.php" look like the second image, using Apache's default 404 page. Is there a way to do this without using .htaccess files, just from PHP? If not, I'll just have to figure out how to mess with Apache settings then.

