Made some changes to the forum, so when a page is not found and generates a 404 error, the site redirects to "Today's Posts" page and added a "Not Found" message:
<?php
header('HTTP/1.0 404 Not Found', true, 404);
header("Location: https://www.unix.com/search.php?do=getdaily&redirect=404");
die();
?>
Results, for example:
