RFC 3041 (rfc3041) - Page 2 of 17

Privacy Extensions for Stateless Address Autoconfiguration in IPv6

RFC 3041      Extensions to IPv6 Address Autoconfiguration  January 2001


Table of Contents

   1.  Introduction.............................................    2
   2.  Background...............................................    3
      2.1.  Extended Use of the Same Identifier.................    3
      2.2.  Address Usage in IPv4 Today.........................    4
      2.3.  The Concern With IPv6 Addresses.....................    5
      2.4.  Possible Approaches.................................    6
   3.  Protocol Description.....................................    7
      3.1.  Assumptions.........................................    8
      3.2.  Generation Of Randomized Interface Identifiers......    9
      3.3.  Generating Temporary Addresses......................   10
      3.4.  Expiration of Temporary Addresses...................   11
      3.5.  Regeneration of Randomized Interface Identifiers....   12
   4.  Implications of Changing Interface Identifiers...........   13
   5.  Defined Constants........................................   14
   6.  Future Work..............................................   14
   7.  Security Considerations..................................   15
   8.  Acknowledgments..........................................   15
   9.  References...............................................   15
   10. Authors' Addresses.......................................   16
   11. Full Copyright Statement.................................   17

1.  Introduction

   Stateless address autoconfiguration [ADDRCONF] defines how an IPv6
   node generates addresses without the need for a DHCP server.  Some
   types of network interfaces come with an embedded IEEE Identifier
   (i.e., a link-layer MAC address), and in those cases stateless
   address autoconfiguration uses the IEEE identifier to generate a 64-
   bit interface identifier [ADDRARCH].  By design, the interface
   identifier is likely to be globally unique when generated in this
   fashion.  The interface identifier is in turn appended to a prefix to
   form a 128-bit IPv6 address.

   All nodes combine interface identifiers (whether derived from an IEEE
   identifier or generated through some other technique) with the
   reserved link-local prefix to generate link-local addresses for their
   attached interfaces.  Additional addresses, including site-local and
   global-scope addresses, are then created by combining prefixes
   advertised in Router Advertisements via Neighbor Discovery
   [DISCOVERY] with the interface identifier.

   Not all nodes and interfaces contain IEEE identifiers.  In such
   cases, an interface identifier is generated through some other means
   (e.g., at random), and the resultant interface identifier is not
   globally unique and may also change over time.  The focus of this
   document is on addresses derived from IEEE identifiers, as the



Narten & Draves             Standards Track