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Versions: 00

v6ops Working Group                                          N. Hilliard
Internet-Draft                                                      INEX
Intended status: Informational                              July 4, 2011
Expires: January 5, 2012


                       A Discard Prefix for IPv6
              draft-hilliard-v6ops-ipv6-discard-prefix-00

Abstract

   Remote triggered black hole filtering describes a method of
   mitigating against denial-of-service attacks by selectively
   discarding traffic based on source or destination address.  This
   document explains why a unique IPv6 prefix should be formally
   assigned by IANA for the purpose of facilitating IPv6 remote
   triggered black hole filtering.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Internet-Drafts are draft documents valid for a maximum of six months
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   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 5, 2012.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as



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   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  A Discard Prefix for IPv6 . . . . . . . . . . . . . . . . . . . 3
   3.  Operational Implications  . . . . . . . . . . . . . . . . . . . 4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 4
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 5





































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1.  Introduction

   Remote triggered black hole (RTBH) filtering describes a class of
   methods of blocking IP traffic to or from a specific destination on a
   network.  These methods operate by setting the next-hop address of an
   IP packet with a specified source or destination address to be a
   unicast prefix which is wired locally or remotely to a router's
   discard or null interface.  Typically, this information is propagated
   throughout an autonomous system using a dynamic routing protocol.  By
   deploying RTBH systems across a network, traffic to or from specific
   destinations may be selectively black-holed in a manner which is
   efficient, scalable and straightforward to implement.  For IPv4, some
   networks configure RTBH installations using [RFC1918] address space
   or the address blocks reserved for documentation in [RFC5737].

   However RTBH configurations are not documentation, but operationally
   important features of many public-facing production networks.
   Furthermore, [RFC3849] specifies that the IPv6 documentation prefix
   should be filtered in both local and public contexts.  On this basis,
   it is suggested that both private network address blocks and
   documentation prefixes described in [RFC5737] are inappropriate for
   the purpose of RTBH configurations.

   While it could be argued that there are other addresses and address
   prefixes which could be used for this purpose (e.g. ::/128), or that
   an operator could assign an address block from their own address
   space for this purposes, there is currently no operational clarity on
   what address block would be appropriate or inappropriate to use for
   this purpose.  By creating an assigned discard prefix for IPv6, the
   IETF will introduce operational clarity and good practice for
   implementation of IPv6 RTBH configurations.


2.  A Discard Prefix for IPv6

   For the purposes of implementing an IPv6 remote triggered black hole
   filter, a unicast address block is required.  There are currently no
   IPv6 unicast address blocks which are specifically nominated for the
   purposes of implementing RTBH filters.

   As [RFC5635] describes situations where more than one discard address
   may be used for implementing multiple remote triggered black holes, a
   single assigned prefix is not sufficient to cover all likely RTBH
   filtering situations.  Consequently, an address block is required.

   The prefix allocated by IANA for the purpose of implementing IPv6
   remote triggered black holes is xxx::/32.




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3.  Operational Implications

   This assignment MAY be carried in a dynamic routing protocol within
   an autonomous system.  The assignment SHOULD NOT be announced to
   third party autonomous systems and IPv6 traffic with an destination
   address within this prefix SHOULD NOT be forwarded to third party
   autonomous systems.

   On networks which implement IPv6 remote triggered black holes, some
   or all of this network block MAY be configured with a destination of
   a discard or null interface on any or all IPv6 routers within the
   autonomous system.


4.  IANA Considerations

   IANA is requested to assign a unique /32 unicast address prefix in
   the IPv6 address registry for the purpose of facilitating remote
   triggered black hole configurations.


5.  Security Considerations

   IPv6 addressing documents do not have any direct impact on Internet
   infrastructure security.


6.  References

6.1.  Normative References

   [RFC5635]  Kumari, W. and D. McPherson, "Remote Triggered Black Hole
              Filtering with Unicast Reverse Path Forwarding (uRPF)",
              RFC 5635, August 2009.

6.2.  Informative References

   [RFC1918]  Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
              E. Lear, "Address Allocation for Private Internets",
              BCP 5, RFC 1918, February 1996.

   [RFC3849]  Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix
              Reserved for Documentation", RFC 3849, July 2004.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.




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   [RFC5737]  Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks
              Reserved for Documentation", RFC 5737, January 2010.


Author's Address

   Nick Hilliard
   INEX
   4027 Kingswood Road
   Dublin  24
   IE

   Email: nick@inex.ie






































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