title: HTTP response code to throttle google search appliance bot (gsa)
body: <p>What HTTP response code should be used to throttle a badly behaved web crawler:</p>
  
  <ul>
  <li><a href="http://en.wikipedia.org/wiki/HTTP_403" rel="nofollow">403 Forbidden</a></li>
  <li><a href="http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#5xx_Server_Error" rel="nofollow">503 Service Unavailable</a></li>
  </ul>
  
  <p>Should any explanation be returned in the headers or in the body?</p>