code: public IPRangeNode findFast(String addr) {
  
  	InetAddress iaddr;
  
  	try {
  
  	    iaddr = InetAddress.getByName(addr);
  	}
  	catch (UnknownHostException ex) {
  
  	    return null;
  	}
  
  	return findFast(iaddr);
      }
docs: performs a binary search over sorted list
  
  @param addr
  @return