title: What is Pipe mode and pass mode in varnish
body: <p>what is pipe mode and pass mode in varnish-cache ... I have been trying to refer to this link to understand varnish. I somewhat understand pass but I'd like a better explanation.. 
  <a href="http://spin.atomicobject.com/2013/01/16/speed-up-website-varnish/" rel="noreferrer">http://spin.atomicobject.com/2013/01/16/speed-up-website-varnish/</a> </p>