title: Turn an AppEngine Blacklist into a Whitelist
body: <p>AppEngine allows the definition of blacklists, to disallow access from certain IP Ranges (http://code.google.com/appengine/docs/python/config/dos.html).</p>
  
  <p>What I would like to do is the inverse: A whitelist, that only allows access from certain IP Ranges.</p>
  
  <p>I am not much of a network specialist, so I would appreciate some help:
  If I wanted to limit access to IPs in the Range from 130.100.120.0 to 130.100.123.255, could that be done using AppEngines blacklist mechanism, or should I do the checking from within my application?</p>
  
  <p>Thanks.</p>