draft-ietf-6man-ipv6only-flag-01.txt   draft-ietf-6man-ipv6only-flag-02.txt 
Network Working Group R. Hinden Network Working Group R. Hinden
Internet-Draft Check Point Software Internet-Draft Check Point Software
Updates: 5175 (if approved) B. Carpenter Updates: 5175 (if approved) B. Carpenter
Intended status: Standards Track Univ. of Auckland Intended status: Standards Track Univ. of Auckland
Expires: January 1, 2019 June 30, 2018 Expires: February 15, 2019 August 14, 2018
IPv6 Router Advertisement IPv6-Only Flag IPv6 Router Advertisement IPv6-Only Flag
draft-ietf-6man-ipv6only-flag-01 draft-ietf-6man-ipv6only-flag-02
Abstract Abstract
This document specifies a Router Advertisement Flag to indicate to This document specifies a Router Advertisement Flag to indicate to
hosts that the administrator has configured the router to advertise hosts that the administrator has configured the router to advertise
that the link is IPv6-Only. This document updates RFC5175. that the link is IPv6-Only. This document updates RFC5175.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 1, 2019. This Internet-Draft will expire on February 15, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Applicability Statements . . . . . . . . . . . . . . . . . . 4 3. Applicability Statements . . . . . . . . . . . . . . . . . . 4
4. IPv6-Only Definition . . . . . . . . . . . . . . . . . . . . 4 4. IPv6-Only Definition . . . . . . . . . . . . . . . . . . . . 4
5. IPv6-Only Flag . . . . . . . . . . . . . . . . . . . . . . . 4 5. IPv6-Only Flag . . . . . . . . . . . . . . . . . . . . . . . 4
6. Router and Operational Considerations . . . . . . . . . . . . 5 6. Router and Operational Considerations . . . . . . . . . . . . 5
7. Host Behavior Considerations . . . . . . . . . . . . . . . . 6 7. Host Behavior Considerations . . . . . . . . . . . . . . . . 6
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
9. Security Considerations . . . . . . . . . . . . . . . . . . . 7 9. Security Considerations . . . . . . . . . . . . . . . . . . . 7
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 8
11. Change log [RFC Editor: Please remove] . . . . . . . . . . . 8 11. Change log [RFC Editor: Please remove] . . . . . . . . . . . 8
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
12.1. Normative References . . . . . . . . . . . . . . . . . . 9 12.1. Normative References . . . . . . . . . . . . . . . . . . 10
12.2. Informative References . . . . . . . . . . . . . . . . . 10 12.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
This document specifies a Router Advertisement Flag to indicate to This document specifies a Router Advertisement Flag to indicate to
hosts that the administrator has configured the router to advertise hosts that the administrator has configured the router to advertise
that the link is IPv6-Only. The flag does not apply to non-default that the link is IPv6-Only. The flag does not apply to non-default
IPv6 routers. IPv6 routers.
Hosts that support IPv4 and IPv6, usually called dual stack hosts, Hosts that support IPv4 and IPv6, usually called dual stack hosts,
need to also work efficiently on IPv6 only links. That is, a link need to also work efficiently on IPv6 only links. That is, a link
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6. Router and Operational Considerations 6. Router and Operational Considerations
Default IPv6 routers that are on an IPv6-Only link SHOULD be Default IPv6 routers that are on an IPv6-Only link SHOULD be
configured to set the IPv6-Only flag to 1 on interfaces on this link. configured to set the IPv6-Only flag to 1 on interfaces on this link.
In all other cases the flag SHOULD NOT be set to 1. In all other cases the flag SHOULD NOT be set to 1.
The intent is that the administrator of the router configures the The intent is that the administrator of the router configures the
router to set the IPv6-Only flag if she/he wants to tell the hosts on router to set the IPv6-Only flag if she/he wants to tell the hosts on
the link that the link is IPv6-Only. This is a configuration flag, the link that the link is IPv6-Only. This is a configuration flag,
it is not something that the router decides on it's own. it is not something that the router decides on it's own. Routers MAY
log a configuration error if the flag is set and IPv4 is still active
on the router.
Operators of large IPv6-only wireless links are advised to also use Operators of large IPv6-only wireless links are advised to also use
Layer 2 techniques to drop IPv4 and ARP packets (Ethertypes 0x0800 Layer 2 techniques to drop IPv4 and ARP packets (Ethertypes 0x0800
and 0x806) at all switches, and to ensure that IPv4 and ARP features and 0x806) at all switches, and to ensure that IPv4 and ARP features
are disabled in all switches. are disabled in all switches.
7. Host Behavior Considerations 7. Host Behavior Considerations
If there are multiple IPv6 default routers on a link, they might send If there are multiple IPv6 default routers on a link, they might send
different values of the flag. If at least one IPv6 default router different values of the flag. If at least one IPv6 default router
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single link. single link.
Note that manipulating the Router Preference [RFC4191] will not Note that manipulating the Router Preference [RFC4191] will not
affect either of these attacks: any IPv6-Only Flag of 0 will always affect either of these attacks: any IPv6-Only Flag of 0 will always
override all Flags set to 1. override all Flags set to 1.
The new flag is neutral from an IPv6 privacy viewpoint, since it does The new flag is neutral from an IPv6 privacy viewpoint, since it does
not affect IPv6 operations in any way. From an IPv4 privacy not affect IPv6 operations in any way. From an IPv4 privacy
viewpoint, it has the potential benefit of suppressing unnecessary viewpoint, it has the potential benefit of suppressing unnecessary
traffic that might reveal the existence of a host and the correlation traffic that might reveal the existence of a host and the correlation
between its hardware and IPv4 addresses. between its hardware and IPv4 addresses. It should be noted that
hosts that don't support this flag are not protected from IPv4-based
attacks.
10. Acknowledgments 10. Acknowledgments
A closely related proposal was published earlier as A closely related proposal was published earlier as
[I-D.ietf-sunset4-noipv4]. [I-D.ietf-sunset4-noipv4].
Helpful comments were received from Lorenzo Colitti, David Farmer, Helpful comments were received from Lorenzo Colitti, David Farmer,
Fernando Gont, Nick Hilliard, Erik Kline, Jen Linkova, Veronika Fernando Gont, Nick Hilliard, Erik Kline, Jen Linkova, Veronika
McKillop, Michael Richardson, Mark Smith, Barbara Stark, Tatuya McKillop, Michael Richardson, Mark Smith, Barbara Stark, Tatuya
Jinmei, Ole Troan, James Woodyatt, and other members of the 6MAN Jinmei, Ole Troan, James Woodyatt, and other members of the 6MAN
working group. working group.
Bjoern Zeeb has also produced a variant of this proposal and proposed Bjoern Zeeb has also produced a variant of this proposal and proposed
an IPv6 transition plan in [I-D.bz-v4goawayflag]. an IPv6 transition plan in [I-D.bz-v4goawayflag].
11. Change log [RFC Editor: Please remove] 11. Change log [RFC Editor: Please remove]
draft-ietf-6man-ipv6only-flag-02, 2018-August-14:
* Added text about logging configuration errors to Section 6
* Added text to Section 9 to clarify that hosts not supporting
this flag are not protected from IPv4-based attacks.
* Editorial changes.
draft-ietf-6man-ipv6only-flag-01, 2018-June-29: draft-ietf-6man-ipv6only-flag-01, 2018-June-29:
* Added text to section that defines what IPv6-Only includes to * Added text to section that defines what IPv6-Only includes to
clarify that only other version of the Internet protocol are in clarify that only other version of the Internet protocol are in
scope. scope.
* Added clarification if the lifetime of all routers expire. * Added clarification if the lifetime of all routers expire.
* Editorial changes. * Editorial changes.
draft-ietf-6man-ipv6only-flag-00, 2018-May-21: draft-ietf-6man-ipv6only-flag-00, 2018-May-21:
 End of changes. 10 change blocks. 
9 lines changed or deleted 20 lines changed or added

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