title: HTTP Cache-Control: What is acceptable default behavior when it's not present?
body: <p>I'm running into some HTTP caching issues, caused by some downstream apps not putting Cache-Control headers on time-sensitive data. I need to make the case that this is a broken situation.</p>
  
  <p>Is there any succinct statement available online about permissible or common response-handling behaviors by caches and agents when the Cache-Control header is not present for HTTP 1.1? I see RFC2616, but it doesn't seem to include any normative or SHOULD statements about responses without a Cache-Control header.</p>