title: How to setup "X-Content-Type-Options : nosniff"on Amazon S3?
body: <p>I met a problem with setting the header "<strong><em>X-Content-Type-Options : nosniff</em></strong>" on static files (js, css, jpg, gif, ...) on my Amazon S3 bucket.</p>
  
  <p>When I try to add it, it says to me : "User-defined metadata keys must start with x-amz-meta-."</p>
  
  <p>How to do it so ? Should I do "<strong><em>x-amz-meta-X-Content-Type-Options</em></strong>"</p>
  
  <p>Thanks in advance !</p>