Indefensible Neighbor Discovery
draft-jaeggli-v6ops-indefensible-nd-01

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v6ops                                                         J. Jaeggli
Internet-Draft                                                    Fastly
Intended status: Informational                              July 2, 2018
Expires: January 3, 2019

                    Indefensible Neighbor Discovery
                 draft-jaeggli-v6ops-indefensible-nd-01

Abstract

   NDP resource exhastion is a problem which cannot fundamently be
   addressed through limited protocol changes or implementation tweaks;
   mitigations proposed in RFC 6583 [RFC6583] may well prevent the
   outright failure of a device under duress.  This draft discusses some
   mitigations which have or can be employeed by networks looking to
   reduce or eliminate the exposure of the Neighbor Discovery Process.

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 January 3, 2019.

Copyright Notice

   Copyright (c) 2018 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
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   include Simplified BSD License text as described in Section 4.e of

Jaeggli                  Expires January 3, 2019                [Page 1]
Internet-Draft                     IND                         July 2018

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  ND under stress . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Ways in which resources are consumed: . . . . . . . . . .   3
   3.  Mitigations . . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  RFC 6583  . . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Link-Local  . . . . . . . . . . . . . . . . . . . . . . .   4
     3.3.  RFC 6164  . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.4.  Firewalls . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.5.  Subnetting  . . . . . . . . . . . . . . . . . . . . . . .   5
     3.6.  Stateless Neighbor Presence Discovery . . . . . . . . . .   5
     3.7.  Solicitied Node Multicast Group Membership  . . . . . . .   6
   4.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Neighbor discovery serves to allow the discovery of hosts and the
   self assignment of resources within the sparse address space of IPv6
   subnets.  Since the definition of Interface IDs and accompanying
   subnet sizes RFC 1885 [RFC1885] the potential has existed for the
   forwarding and control plane resources of a router to be greatly
   exceeded by locally or remotely triggered attempts to desocver
   connected neighbors.  The problem of the number of adjacencies that
   can reasonably be supported and signaled in not unique to IPv6 though
   it is especially accute there.  It also exists in IPv4 as well as
   other non-internet protocols.  Practical scaling limits of the number
   of adjaciences or amount of signaling serve as incentives for
   operators to limit the size and number of participants in layer-2
   domains.

   Because of the size of typical IPv6 Interface IDs as well as the
   property of self-assignment, IPv6 subnets and connected devices are
   particularly exposed to resource consumption; therefore proactive
   mitigations are required to limit the potential for resource
   consumption resulting in Denial of Service.  In RFC 6583 [RFC6583],
   we detailed the threat posed by neighbor discovery resource
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