Internet DRAFT - draft-zerorafolks-6man-ra-zero-lifetime
draft-zerorafolks-6man-ra-zero-lifetime
IPv6 Maintenance L. Colitti
Internet-Draft E. Kline
Updates: 4862 (if approved) Google
Intended status: Standards Track June 30, 2018
Expires: January 1, 2019
Zero valid lifetimes on point-to-point links
draft-zerorafolks-6man-ra-zero-lifetime-00
Abstract
This document allows implementations to accept low or zero valid
lifetimes in Router Advertisement Prefix Information Options in cases
where it is known that there can only be one router on the link.
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
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This Internet-Draft will expire on January 1, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Cases when it is useful to reduce Valid Lifetime to zero . . 2
3. Changes to RFC 4862 . . . . . . . . . . . . . . . . . . . . . 2
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 3
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 3
6.1. Normative References . . . . . . . . . . . . . . . . . . 3
6.2. Informative References . . . . . . . . . . . . . . . . . 3
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 3
1. Introduction
Currently, Prefix Information Options in Router Advertisements cannot
reduce the Valid Lifetime of an IPv6 address below 2 hours. This is
due to an explicit restriction in Section 5.5.3 of [RFC4862]. The
reason is to avoid a denial-of-service attack whereby a malicious
attacker can cause a node's addresses to expire prematurely by
sending a Router Advertisement with a low Valid Lifetime.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Cases when it is useful to reduce Valid Lifetime to zero
In some cases, it is useful for the network to inform the host that a
given prefix is no longer valid or will shortly no longer be valid.
One example is if the host has moved beyond the mobility scope of the
prefix and the network will no longer deliver packets for that prefix
to the host. The host can thus terminate any upper-layer connections
using that prefix and notify applications that continued
communication will require using a new source address.
In order to ensure uninterrupted communications and no dispution to
applications, this should be done only if the host already has other
IPv6 addresses of equivalent scope and sufficient Valid Lifetime.
3. Changes to RFC 4862
The following clause is added between points 1 and 2 of clause e,
Section 5.5.3 of [RFC4862]:
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2. If the link-layer guarantees that there is only one node on the
link from which the host can receive Router Advertiesements (e.g.,
if the link is a point-to-point link, such as a PPP link or a 3GPP
link as defined in [RFC6459]), and the link has another prefix of
the same scope with sufficient Valid Lifetime, set the valid
lifetime of the corresponding address to the advertised Valid
Lifetime.
4. IANA Considerations
This memo includes no request to IANA.
5. Security Considerations
The denial-of-service attack that motivated this restriction cannot
be mounted on a link where no other devices can send Router
Advertisements to the host.
6. References
6.1. 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/info/rfc2119>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
6.2. Informative References
[RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen,
T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, DOI 10.17487/RFC6459, January 2012,
<https://www.rfc-editor.org/info/rfc6459>.
Authors' Addresses
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Internet-DraftZero valid lifetimes on point-to-point links June 2018
Lorenzo Colitti
Google
Roppongi 6-10-1
Minato, Tokyo 106-6126
JP
Email: lorenzo@google.com
Erik Kline
Google
Roppongi 6-10-1
Minato, Tokyo 106-6126
JP
Email: ek@google.com
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