title: Does a caching-nameserver usually cache the negative DNS response SERVFAIL
body: <p>Does a caching-nameserver usually cache the negative DNS response SERVFAIL? </p>
  
  <p>EDIT:
  To clarify the question, I can see the caching nameserver caching negative responses NXDOMAIN, NODATA. But it does not do this for SERVFAIL responses. Is this intentional?</p>