Additional Transition Functionality for IPv6
RFC 8136
Independent Submission B. Carpenter
Request for Comments: 8136 Univ. of Auckland
Category: Informational R. Hinden
ISSN: 2070-1721 Check Point Software
1 April 2017
Additional Transition Functionality for IPv6
Abstract
This document proposes an additional mechanism intended to both
facilitate transition from IPv4 to IPv6 and improve the latter's
security and privacy.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc8136.
Copyright Notice
Copyright (c) 2017 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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RFC 8136 Additional IPv6 Transition Functionality 1 April 2017
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2. Required Function of All IPv4 Nodes . . . . . . . . . . . . . 2
3. Security Flag for IPv6 Packets . . . . . . . . . . . . . . . 3
4. Advanced Solution . . . . . . . . . . . . . . . . . . . . . . 4
4.1. Privacy Extension . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
In a recent statement [IABv6], the Internet Architecture Board deemed
that the Internet Engineering Task Force is expected to "stop
requiring IPv4 compatibility in new or extended protocols" and that
future work will "optimize for and depend on IPv6". In the interest
of promoting these goals, this memo makes an important change to IPv4
node requirements [RFC1122] and adds a missing security feature to
IPv6 [RFC2460].
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are not to be interpreted as described in
[RFC2119].
2. Required Function of All IPv4 Nodes
To ensure that all routers, firewalls, load balancers, and other
forms of middleboxes can readily identify IPv4 packets and deal with
them appropriately (selective dropping, switching to the slow path
through a router, sending them to the longest path first, etc.), all
IPv4 nodes MUST set the security flag defined by [RFC3514] to 1.
This should be sufficient to ensure that implementers of dual stack
applications prefer IPv6 when given the choice, and that the Happy
Eyeballs algorithm [RFC6555] will usually favour the IPv6 path.
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RFC 8136 Additional IPv6 Transition Functionality 1 April 2017
3. Security Flag for IPv6 Packets
The above requirement will somewhat nullify the practical effect of
the IPv4 security flag for benign traffic, but this disadvantage can
readily be overcome by adding an equivalent flag for IPv6; in fact,
this is highly desirable to maintain feature equivalence between IPv4
and IPv6. Fortunately, this can easily be achieved since IPv6
supplies so many bits. The solution defined here is that the
Security Flag bit for an IPv6 packet is simply the parity of the
source address of the packet. In other words, if the source address
contains an odd number of 1s, the flag is True; otherwise, it's
False. All other considerations for the flag are exactly as
described in [RFC3514].
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