--- a/src/helper/ipv4-address-helper.h	Sat Oct 03 16:21:58 2009 -0700
+++ b/src/helper/ipv4-address-helper.h	Sun Oct 04 20:52:24 2009 -0700
@@ -176,6 +176,9 @@
   Ipv4InterfaceContainer Assign (const NetDeviceContainer &c);
 
 private:
+  /**
+   * @internal
+   */
   uint32_t NumAddressBits (uint32_t maskbits) const;
 
   uint32_t m_network;