On my employer web server, we have 200+ PHP applications with this kind of code to allow download of a file :
header('Content-Disposition: attachment; filename="file.pdf"'); header('Expires: 0'); header('Pragma: no-cache');
It run fine on the old server (Debian Lenny, PHP 5.2, Apache 2.2.9), but fail on IE8 with the new one (Debian Squeeze, PHP 5.2, Apache 2.2.16). Others browsers are fines. We only access file via HTTPS, never HTTP. We do not find any difference between the conf file, but replacing no-cache by private correct the problem with IE. Where can we look to understand where the difference is?