As I have for a few other sites, I'm writing a simple PHP-based digest auth. However, for some reason it isn't working on Heliohost (my lu.heliohost.org). I've confirmed, using Wireshark, that the Authenticate header is actually getting sent from the browser: Authorization: Digest username=\"gtoombs\", realm=\"lu.heliohost.org/cellrepair\", nonce=\"a120c81273e142ad51f781647dfbf4a6\", uri=\"/cellrepair/hashtest.php\", algorithm=MD5, response=\"e019b2f521d16e90a4c31ee27200b276\", opaque=\"789a54386ec7b7480117fa979351d9cb\", qop=auth, nc=00000001, cnonce=\"73b777d243a0a3e2\" Unfortunately, from PHP, neither $_SERVER['Authorization'] nor $_SERVER['PHP_AUTH_DIGEST'] are set, and apache_request_headers() does not work. It seems to me that this could be a server configuration issue?