header("Content-disposition: filename=file.name);
header("Content-type: application/octetstream");
header('Expires: '.gmdate('D, d M Y H:i:s').' GMT');
header('Last-Modified: '.gmdate('D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-store, no-cache, must-revalidate'); // HTTP/1.1
header('Cache-Control: pre-check=0, post-check=0, max-age=0'); // HTTP/1.1
header('Pragma: no-cache'); // HTTP/1.0

Това работи при почти всички

root@localhost#cd /pub
root@localhost#more beer