Index: includes/bootstrap.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/bootstrap.inc,v
retrieving revision 1.106
diff -u -F^f -r1.106 bootstrap.inc
--- includes/bootstrap.inc	13 Jul 2006 13:11:36 -0000	1.106
+++ includes/bootstrap.inc	21 Jul 2006 14:45:55 -0000
@@ -400,7 +400,9 @@ function drupal_page_header() {
 
     // The type checking here is very important, be careful when changing entries.
     if (($modified_since !== NULL || $none_match !== NULL) && $modified_since !== FALSE && $none_match !== FALSE) {
-      header('HTTP/1.0 304 Not Modified');
+      header('HTTP/1.1 304 Not Modified');
+      // All 304 responses must send an etag if the 200 response for the same object contained an etag
+      header('Etag: $etag');
       exit();
     }