title: How long does a reverse DNS lookup take?
body: <p>How long should I expect a reverse lookup take?  100 milliseconds?  1 second?  10 second?  30 seconds?  What's your experience?</p>
  
  <p>Why?  We're debating adding a feature to our server software which would require a reverse DNS lookup each time a client connects.  The lookup would be done synchronously, so I'm worried that it could slow connection-times down a lot.  I just wanted to hear other people's experience regarding reverse DNS lookup times.</p>