IPv6 Sparse Random Addressing
draft-ideafarm-ipv6-sparse-random-addressing-00

IP Version 6 Working Group                                W. O. Ideafarm
Internet-Draft                                              IDEAFARM.COM
Intended status: Informational                           16 January 2026
Expires: 20 July 2026

                     IPv6 Sparse Random Addressing
            draft-ideafarm-ipv6-sparse-random-addressing-00

Abstract

   The IPv6 address space is huge.  This document discusses how "sparse
   random addressing" can be used to defeat DDOS attacks, and also to
   create paid-access websites.  The essential idea is to use the host
   ID portion of an IPv6 address as a time-based password that only paid
   subscribers know.  (They know it by running a program on the device
   that they use to access the website.  That program uses the current
   time and a secret shared with the web server to calculate the current
   host ID.)  Each subscriber has a unique secret so, at any point in
   time, uses a unique IPv6 address to access the website.  Sparseness
   prevents attack packets from reaching the web server.  Uniqueness
   creates accountability.  To protect routers from flood attacks, the
   globally routable /48 prefix is also randomized, in a way that
   exploits BGP route propagation delay to partially or completely quash
   the flooding at the source, thereby protecting all upstream routers.

   This early draft only contains a conceptual overview.

About This Document

   This note is to be removed before publishing as an RFC.

   The latest revision of this draft can be found at
   https://ideafarm.github.io/RFC-IPv6-Sparse-Random-Addressing/draft-
   ideafarm-ipv6-sparse-random-addressing.html.  Status information for
   this document may be found at https://datatracker.ietf.org/doc/draft-
   ideafarm-ipv6-sparse-random-addressing/.

   Discussion of this document takes place on the IP Version 6 Working
   Group Working Group mailing list (mailto:ipv6@ietf.org), which is
   archived at https://mailarchive.ietf.org/arch/browse/ipv6.  Subscribe
   at https://www.ietf.org/mailman/listinfo/ipv6/.

   Source for this draft and an issue tracker can be found at
   https://github.com/ideafarm/RFC-IPv6-Sparse-Random-Addressing.

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Status of This Memo

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

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   This Internet-Draft will expire on 20 July 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   Please review these documents carefully, as they describe your rights
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   5
   3.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   5.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The IPv6 address space is huge.  For example, it contains 68 billion
   prefixes that are 36 bits long, so every human being alive today
   could be given a /36 prefix for his or her exclusive use for life,
   and this policy could continue indefinitely without ever consuming
   more than a small fraction of the available address space.  Yet all
   of the Tier-1 networking providers and all of the Regional Internet
   Registries still operate as if addresses are scarce and that each
   device should only have a single, unchanging, published, address.

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   For example, ARIN's IPv6 block assignment policy requires that an
   applicant must have multiple physical locations to obtain a prefix
   shorter than the minimum prefix length (48 bits) that is globally
   routable, and that the length of the prefix granted will depend upon
   the number of physical locations such that each location is only
   given a single routable prefix.  The policy neither contemplates nor
   provides for using the huge IPv6 address space in any manner other
   than the way that IPv4 addresses have been used for a half century,
   one unchanging public address per device.

   This document proposes that portions of an IPv6 address be used as
   time-based passwords, describes a particular experimental
   implementation and preliminary findings from studying it, and
   discusses the costs and benefits, both to individual organizations
   and to the Internet community, of using the huge IPv6 address space
   in this new way.

   Time-based passwords have become widely used to provide "two factor
   authentication" when a user logs into a website.  In that
   application, brute force password attacks are prevented by requiring
   that the user also enter a time-based password that is calculated
   using the current time and a secret that only he and the web server
   knows.  Current practice allocates 64 bits for the host ID portion of
   an IPv6 address, which is huge relative to the number of distinct
   values needed to identify each host on a physical link of any
   conceivable size.  By using some (or all) of those bits as a time-
   based password, attack packets can be prevented, by sparseness, from
   reaching that server.

   For such a scheme to work, a would-be attacker must not be able to
   discover the secret.  A simple way to prevent this is to give a
   unique secret to each paid subscriber, which requires that the server
   accepts packets from many IPv6 addresses, one for each subscriber.
   An attacker can purchase a subscription and use a tool like Wireshark
   to see the current IPv6 address that gives him access to the server,
   but if he uses that information to attack the server, the IPv6
   addresses that the attack uses will reveal his identity.

   A similar approach can be used to secure upstream routers from a
   flooding attack.  A well funded and motivated attacker might use a
   botnet to flood the /48 prefix with randomly addressed packets, not
   to reach the web server, but to get the upstream ISP to nullroute the
   entire prefix.  Randomizing a portion of the /48 prefix can mitigate
   and, in some scenarios, entirely quash such an attack.

   Using the huge IPv6 address space in this way consumes orders of
   magnitude more addresses, so such applications revive address
   exhaustion concerns.  Fortunately, these concerns are mitigated by

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   two facts.  First, the space is so huge that, even with current
   routing practice, every person on the planet can be given a /36
   prefix for his exclusive use, and each such block contains 4096
   routable blocks (blocks that use a 48 bit prefix), since 12 bits are
   available for randomizing the prefix.  Second, the RIR's can reserve
   a portion of the address space for sparse random addressing in a way
   that permits routers to enforce a requirement that routes in that
   space are sparse.  This would enable routers to treat much longer
   prefixes as globally routable in that space.  (In that space, the
   number of routes in the global routing table would be constrained by
   enforced sparseness rather than prefix length.)  It might take
   several years for such prefixes to become reliably routable, but
   after that transition, sparse random addressing would no longer
   require prefixes shorter than /48.  So sparse random addressing would
   not, long term, create an address exhaustion concern.

   Explosive growth of the global routing table, not address exhaustion,
   will likely be what constrains use of the huge IPv6 address space.
   Even if prefixes longer than 48 bits are dropped, that leaves up to
   281 trillion prefixes requiring global routability.  Sparse random
   addressing "theoretically" does not increase the number of routes
   advertised, but in practice it will, because multiple routes must be
   advertised at the same time.  As discussed below, the objective in
   randomizing the prefix is to exploit asymmetries that put a DDOS
   attacker and his botnet at a disadvantage.  In the experimental
   implementation, this is done by withdrawing the eldest prefix and
   advertising a new prefix approximately once each minute, with each
   prefix being advertised for about 15 minutes.  Deploying sparse
   random addressing in this way, with each server cluster emitting a
   BGP UPDATE (add+withdraw) message once each minute, would place a new
   processing burden on the global BGP system.

   This document is a working draft that presents the current status of
   an experimental implementation of sparse random addressing using a
   single router and a single web server at a single datacenter to serve
   a simple paid-access website.  The initial objective is to get it all
   to work, and then to assess robustness.  (Can it effectively
   withstand a DDOS attack?)  This document will specify the
   experimental system in enough detail to enable others to replicate
   the experiment, using the same proprietary open source software.  In
   this initial phase, the focus will be to find out whether it is
   possible for a well funded and motivated DDOS attacker to bring down
   the experimental website.

   The next research objective will be to quantify the resource impact
   that the deployment of such systems will have on the global BGP and
   routing system.  If the benefits of defeating DDOS attacks and of
   facilitating paid-access websites are significant, the Internet

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   community can then discuss what level of incremental processing cost
   it is willing to bear, in the form of more expensive routers and
   higher energy consumption, to obtain those benefits.

   At this early stage, this approach appears to promise to give the
   Internet community the "upper hand" in its battle against bad actors
   who use botnets to attack servers, and sparse random addressing,
   which can only be done with IPv6, just might be the "killer app" that
   could finally drive universal migration to IPv6.

2.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Security Considerations

   [TODO Security]

4.  IANA Considerations

   This document proposes that a /16 block be reserved for sparse random
   addressing:

   Block: 2003::/16 Name: Sparse Random Addressing RFC: [This document]
   Allocation Date: [TBD] Termination Date: N/A Source: TRUE
   Destination: TRUE Forwardable: TRUE Globally Reachable: TRUE
   Reserved-by-Protocol: TRUE

   Required IP compliant processing: External BGP peers SHALL NOT drop
   routes for prefixes within this block based upon prefix lengths from
   /0 through /128.  To limit the number of global routing table entries
   for destinations in this block, routers SHALL enforce sparseness,
   using any of the algorithms specified in this document.

5.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/rfc/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.

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Acknowledgments

   The author thanks the ARIN Regional Internet Registry for temporarily
   providing an IPv6 /36 block to accommodate his study of, and
   experimentation with, sparse random addressing.

Author's Address

   Wo Of Ideafarm
   IDEAFARM.COM
   Email: wo.ideafarm.publication.delayed.4.yrs@ideafarm.com

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