Network Working Group J. Arkko
Internet-Draft Ericsson
Expires: September 1, 2003 March 3, 2003
Effects of ICMPv6 on IKE
draft-arkko-icmpv6-ike-effects-02.txt
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as
Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at http://
www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on September 1, 2003.
Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
The ICMPv6 protocol provides many functions which in IPv4 were either
non-existent or provided by lower layers. IPv6 architecture also
makes it possible to secure all IP packets using IPsec, even ICMPv6
messages. IPsec architecture has a Security Policy Database that
specifies which traffic is protected, and how. It turns out that the
specification of policies in the presence of ICMPv6 traffic is hard,
particularly with ICMPv6 packets related to Neighbor Discovery.
Sound looking policies may easily lead to loops: The establishment of
security requires Neighbor Discovery messages which can not be sent
since security has not been established yet. The purpose of this
draft is to inform system administrators and IPsec implementors in
which manner they can handle the ICMPv6 messages. Common
Arkko Expires September 1, 2003 [Page 1]
Internet-Draft ICMPv6 and IKE March 2003
understanding of the way that these messages are handled is also
necessary for interoperability, in case vendors hardcode such rules
in to products.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Neighbor Discovery and ICMPv6 Tasks . . . . . . . . . . . . 5
3.1 Path MTU Discovery . . . . . . . . . . . . . . . . . . . 5
3.2 Error Notification . . . . . . . . . . . . . . . . . . . 5
3.3 Informational Notifications . . . . . . . . . . . . . . 5
3.4 Router and Prefix Discovery . . . . . . . . . . . . . . 5
3.5 Address Autoconfiguration . . . . . . . . . . . . . . . 6
3.6 Duplicate Address Detection . . . . . . . . . . . . . . 6
3.7 Address Resolution . . . . . . . . . . . . . . . . . . . 6
3.8 Neighbor Reachability Detection . . . . . . . . . . . . 6
3.9 Redirect . . . . . . . . . . . . . . . . . . . . . . . . 7
3.10 Router Renumbering . . . . . . . . . . . . . . . . . . . 7
4. Factors Affecting the Policy Rules . . . . . . . . . . . . . 8
4.1 Nature of the Addresses . . . . . . . . . . . . . . . . 8
4.2 Network Topology . . . . . . . . . . . . . . . . . . . . 8
4.3 Role in Estaliblishing Communications . . . . . . . . . 9
4.4 Protecting the Infrastructure versus Communications . .10
5. Analysis of the ICMPv6 Messages . . . . . . . . . . . . . . 11
5.1 Destination Unreachable . . . . . . . . . . . . . . . .11
5.2 Packet Too Big . . . . . . . . . . . . . . . . . . . . .11
5.3 Time Exceeded . . . . . . . . . . . . . . . . . . . . .11
5.4 Parameter Problem . . . . . . . . . . . . . . . . . . .11
5.5 Echo Request . . . . . . . . . . . . . . . . . . . . . .11
5.6 Echo Reply . . . . . . . . . . . . . . . . . . . . . . .12
5.7 Redirect . . . . . . . . . . . . . . . . . . . . . . . .12
5.8 Router Solicitation . . . . . . . . . . . . . . . . . .12
5.9 Router Advertisement . . . . . . . . . . . . . . . . . .12
5.10 Neighbour Solicitation . . . . . . . . . . . . . . . . .12
5.11 Neighbour Advertisement . . . . . . . . . . . . . . . .12
5.12 Router Renumbering . . . . . . . . . . . . . . . . . . .13
6. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 14
7. Further Work . . . . . . . . . . . . . . . . . . . . . . . . 16
Normative References . . . . . . . . . . . . . . . . . . . . 17
Informative References . . . . . . . . . . . . . . . . . . . 18
Author's Address . . . . . . . . . . . . . . . . . . . . . . 18
A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19
Intellectual Property and Copyright Statements . . . . . . . 20
Arkko Expires September 1, 2003 [Page 2]
Internet-Draft ICMPv6 and IKE March 2003
1. Introduction
The ICMPv6 [8] and IPv6 Neighbor Discovery [6] protocols provide many
functions which in IPv4 were either non-existent or provided by lower
layers. For instance, IPv6 implements address resolution using an IP
packet, ICMPv6 Neighbour Solicitation message. In contrast, IPv4
uses an ARP message at a lower layer.
IPv6 architecture makes it possible to secure all IP packets using
IPsec [4], even ICMPv6 and Neighbor Discovery messages and even to
multicast addresses. IPsec architecture has a Security Policy
Database that specifies which traffic is protected, and how. It
turns out that the specification of policies in the presence of
Neighbor Discovery traffic is not easy. For instance, a simple
policy of protecting all traffic between two hosts on the same
network would trap even address resolution messages, leading to a
situation where IKE ca not establish a Security Association since in
order to send the IKE UDP packets one would have had to send the
Neighbour Solicitation Message, which would have required an SA.
The purpose of this draft is to inform system administrators and
IPsec implementors in which manner they can handle the Neighbor
Discovery messages. System administrators do not want to study the
IPv6 specifications in order to understand how they shall configure
their routers. IPsec implementors want to understand what kind of
policies they can offer with respect to the Neighbor Discovery
messages.
Common understanding of the way that these messages are handled is
also very much necessary for interoperability, as some vendors may be
hardcoding some of the low-level policy operations in their products.
If the rules between two vendors' products are incompatible for a
particular message we may end with the sender sending cleartext and
the receiver requiring IPsec, causing the packet to be dropped and
possibly all connectivity between the two nodes lost.
This document does not imply any changes to the ICMPv6, Neighbor
Discovery, IPsec, or IKE specifications. It is merely provided for
configuration guidance.
Arkko Expires September 1, 2003 [Page 3]
Internet-Draft ICMPv6 and IKE March 2003
2. Terminology
The keywords "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 [2].
Arkko Expires September 1, 2003 [Page 4]
Internet-Draft ICMPv6 and IKE March 2003
3. Neighbor Discovery and ICMPv6 Tasks
In IPv6, ICMP has several tasks, and many of these tasks are
overloaded on a few central message types such as the Neighbour
Discovery message. In this chapter we explain the tasks and their
effects in order to understand better how the messages should be
treated.
3.1 Path MTU Discovery
Path MTUs are dynamically determined by IPv6 in order to optimize the
size of the packets sent to a particular destination [1].
The ICMPv6 Packet Too Big messages [8] are used as a part of the Path
MTU Discovery procedure.
3.2 Error Notification
ICMPv6 handles basic error situations of the IP layer, such as
finding out that a particular destination is not available.
The Destination Unreachable, Packet Too Big, Parameter Problem, and
Time Exceeded messages are a part of the error handling procedure
[8]. Note that the Packet Too Big message also plays a role in the
Path MTU Discovery procedure.
3.3 Informational Notifications
For debugging and network analysis purposes, ICMPv6 includes
informational messages [8]. These message are necessary also in
IPsec contexts and over IPsec tunnels due to the complex nature of
some tunnel setups.
The Echo Request and Echo Reply messages are used solely for this
purpose.
3.4 Router and Prefix Discovery
Router and prefix discovery is a part of the Neighbour Discovery
protocol [6], which in turn is a part of the ICMPv6. The main
purpose of the router discovery is to find neighboring routers that
are willing to forward packets on the behalf of hosts. Prefix
discovery involves determining which destinations are local for an
attached link. This information is used both by the address
autoconfiguration process, and routing. Typically, address
autoconfiguration and other tasks can not proceed at all until the
router discovery process has run.
Arkko Expires September 1, 2003 [Page 5]
Internet-Draft ICMPv6 and IKE March 2003
The Router Solicitation and Router Advertisement messages are used
for this and only this purpose.
3.5 Address Autoconfiguration
Address autoconfiguration is another part of the Neighbour Discovery
protocol [6]. It's purpose is to automatically assign addresses to
interfaces. It comes in two variants, stateless and statefull. In
this document we consider only the stateless autoconfiguration
aspects. Obviously, no higher layer traffic can be sent until all
participating nodes have addresses. This includes also IKE UDP
traffic.
The Neighbour Solicitation and Advertisement messages are used for
this purpose, among other things. Furthermore, Router and Prefix
Discovery and Duplicate Address Detection have an effect to the
Address Autoconfiguration tasks.
3.6 Duplicate Address Detection
As a part of the stateless address autoconfiguration procedure, nodes
check for duplicate addresses prior to assigning an address to an
interface [7]. This procedure uses the same messages as the
Neighbour Discovery protocol. Since the rules outlined in RFC 2462
[7] forbid the use of an address for both sending and receiving
packets until it has been found unique, no higher layer traffic is
possible until this procedure has completed.
The Neighbour Solicitation and Advertisement messages are used also
for this purpose.
3.7 Address Resolution
In address resolution, nodes determine the link-layer address of a
local destination given only the destination's IP address [6].
Again, no higher level traffic can proceed until the sender knows the
hardware address of the destination or the next hop router.
The Neighbour Solicitation and Advertisement messages are used also
for this purpose.
3.8 Neighbor Reachability Detection
Hosts monitor the reachability of local destinations and routers in
the Neighbour Unreachability procedure, which is a part of the
Neighbour Discovery protocol [6]. No higher level traffic can
proceed if this procedure flushes out neighbour cache entries after
(perhaps incorrectly) determining that the peer is not reachable.
Arkko Expires September 1, 2003 [Page 6]
Internet-Draft ICMPv6 and IKE March 2003
The Neighbour Solicitation and Advertisement messages are used also
for this purpose.
3.9 Redirect
In the Redirect procedure, a router informs a host of a better
first-hop node to reach a particular destination [6]. It is a part
of the Neighbour Discovery protocol. As routers forward packets
regardless of them being sent first to the wrong place,
communications can still be established without the ability to
process Redirect messages.
The Redirect message is used solely for the Redirect procedure.
3.10 Router Renumbering
This procedure [9] allows address prefixes on routers to be
configured and reconfigured in the similar manner as Neighbor
Discovery and Address Autoconfiguration works for hosts. Incorrect
processing or blocking of messages related to this procedure may
render a node's address sets invalid, thereby preventing further
communications.
The Router Renumbering message is used solely for the Router
Renumbering procedure.
Arkko Expires September 1, 2003 [Page 7]
Internet-Draft ICMPv6 and IKE March 2003
4. Factors Affecting the Policy Rules
4.1 Nature of the Addresses
Neighbor Discovery messages are sent using various kinds of source
and destination address types. The nature of the destination address
is of relevance here, as the destination address is used to find the
right security association. The destination address can be either a
well known multicast address, a computed multicast address, such as
the solicited-node multicast address, or a unicast address. Many
Neighbor Discovery messages use multicast addresses in most cases.
Some messages can also be sent to unicast addresses in certain
situations. For instance, the Neighbor Solicitation messages are
usually sent to multicast addresses, but the Neighbor Advertisement
messages are also sent to unicast addresses when sent as a response
to a node that has an address.
ICMPv6 messages are sent using various kinds of source and
destination address types. The source address is usually a unicast
address, but during address autoconfiguration message exchanges, the
unspecified address :: is also used as a source address [7]. The
destination address can be either a well known multicast address, a
generated multicast address such as the solicited-node multicast
address, or a unicast address. While many ICMPv6 messages use
multicast addresses most of the time, some also use unicast addresses
sometimes. For instance, the Neighbour Solicitation messages are
usually sent to multicast addresses, but the Neighbour Advertisement
messages are also sent to unicast addresses when sent as a response
to a node that has an address.
IPsec [4] can be used for the protection of both unicast and
multicast traffic. However, in order to automatically negotiate
mutually acceptable security associations and to refresh keys, IKE
[5] needs to be used. IKE is only capable of negotiating SAs for
unicast communications.
Obviously, policies MUST be configured so that multicast traffic does
not require dynamic SAs. However, while this is a necessary
condition it is not sufficient to make sure that that IKE works. The
policies MUST also exclude unicast traffic which is contains ICMPv6
messages required before UDP can work between the two nodes.
4.2 Network Topology
ICMP traffic has different implications for hosts and security
gateways. In general, security gateways SHOULD carry all ICMP
traffic related to the protected traffic in the same tunnel as the
traffic itself. For instance, when an ICMPv6 Packet Too Big message
Arkko Expires September 1, 2003 [Page 8]
Internet-Draft ICMPv6 and IKE March 2003
is generated on the unprotected segment of a packet's path, that
message should relayed through the tunnel to ensure that the sender
recognizes the MTU problem.
Between hosts similar rules apply. However, messages related to the
establishment of communication between the hosts - such as for
address resolution - MUST NOT be passed through the tunnel at least
when the tunnel does not exist yet and IKE would be needed to
establish it.
Note that the distinctions in network topology are more due to the
actual network architecture than the selected IPsec mode, be it
tunnel or transport.
ICMPv6 messages can be classified according to whether they are meant
for end-to-end communications or communications within a link. There
are also messages that we classify as 'any-to-end', which can be sent
from any point within a path back to the source, typically to
announce an error in processing the original packet. For instance,
the address resolution messages are solely for local communications
[6], whereas the Destination Unreachable messages are any-to-end in
nature. End-to-end and any-to-end messages MUST always be passed
through tunnels. Local messages may be passed through IPsec process
under certain conditions.
4.3 Role in Estaliblishing Communications
ICMPv6 messages can also be classified according to their role for
establishing communications between two nodes. For the purposes of
this discussion, the relevant issue is whether or not the messages
must be passed through before IKE can use UDP packets to negotiate
SAs. For instance, address autoconfiguration, duplicate address
detection, and address resolution obviously MUST be completed before
UDP packets can be passed.
Neighbour reachability detection is also capable of disrupting IKE
communications. The reference [6] states the following:
In some cases (e.g., UDP-based protocols and routers
forwarding packets to hosts) such reachability information
may not be readily available from upper-layer protocols.
When no hints are available and a node is sending packets
to a neighbor, the node actively probes the neighbor using
unicast Neighbor Solicitation messages to verify that the
forward path is still working.
This means that unless the IKE implementation explicitly handles
forward progress notifications towards the IPv6 stack, the stack can
Arkko Expires September 1, 2003 [Page 9]
Internet-Draft ICMPv6 and IKE March 2003
not know about the reachability towards the other host. Since the
hosts may be using tunnel mode and other address in the inner packets
than the regular addresses on the hosts, the stack can not learn of
forward progress through regular IPsec AH or ESP packets.
Therefore, neighbour reachability MUST also be allowed to work
independent of IKE SA establishment.
As IKE messages may contain certificates, it is quite possible that
an MTU limit may be exceeded somewhere within the network. If this
is possible in a given network, the policies MUST allow ICMP Packet
Too Big messages to be received. Note that these messages may well
be received either in the clear, on manually configured SAs, or on
dynamic SAs. If the router generating the Packet Too Big message
does not yet have an SA with the original host, it can initiate IKE
negotiations to create one. In case that this new negotiation fails
due to reaching another MTU limit, other routers may be involved
along the way. But ultimately the process reaches the closest router
to which the MTU is known and will not cause any ICMP error messages.
4.4 Protecting the Infrastructure versus Communications
IPsec can be used to protect the end-to-end communications or the
underlying control messages (such as ICMPv6). It can even be used to
protect both. Since many of the control messages are sent to
multicast addresses, if IPsec is used then manual SA configuration
MUST be performed instead of IKE-based SA negotiation.
As we have talked about some messages in some situations having to be
independent of IKE, it does not necessarily imply that they have to
passed through in the clear. Instead, systems MAY use manually
configured IPsec SAs to protect e.g. all ICMPv6 communications
within one network. (Note that setting these manual SAs up requires
some care as discussed in [13].)
A plausible security policy configuration could therefore be one
where all ICMPv6 messages within the local network must be protected
by manual SAs, and all other communications must be protected by
IKE-negotiated SAs.
Arkko Expires September 1, 2003 [Page 10]
Internet-Draft ICMPv6 and IKE March 2003
5. Analysis of the ICMPv6 Messages
5.1 Destination Unreachable
This message is always sent between unicast addresses [8]. It is an
end-to-end message Destination Unreachable is never a relevant
message for establishing dynamic SAs, unless advanced failover
schemes rely on the knowledge to quickly determine unreachable IKE
peers.
5.2 Packet Too Big
This message is also always sent between unicast addresses [8] even
if might be sent as a response to a multicast message. It is an
end-to-end message.
Packet Too Big has, however, a role in establishing communications.
End-to-end communications, that is. In order to pass through long
IKE packets, Packet Too Big responses from the network MUST be
considered. Therefore, it MUST be possible for policies to be
configured so that such messages can be received. Note that as
dicussed previously, the Packet Too Big messages themselves can be
protected in various ways.
5.3 Time Exceeded
This message is also always sent between unicast addresses [8] and is
an end-to-end message. Like Packet Too Big, it too has a role in
establishing end-to-end communications under certain special
situations.
5.4 Parameter Problem
This message is similar to Packet Too Big in the sense that it uses
only unicast messages even if it could be sent as a response to a
multicast packet. It's role is also end-to-end. While in theory its
role in establishing communications is similar to Packet Too Big and
Time Exceeded, in practise it is hard to see the kind of IKE and IPv6
stack version problem that could result in this message being sent.
5.5 Echo Request
Echo Request uses unicast addresses as source addresses, but may be
sent to any legal IPv6 address, even multicast and anycast addresses
[8]. Echo Requests run end-to-end but never have a role in
establishing communications.
Arkko Expires September 1, 2003 [Page 11]
Internet-Draft ICMPv6 and IKE March 2003
5.6 Echo Reply
Echo Reply is similar to Echo Request in other respects, but uses
only unicast addresses.
5.7 Redirect
The Redirect message is always sent between unicast addresses [6].
It is only used for local purposes, not for end-to-end
communications. It is not strictly necessary in order to establish
communications. Nevertheless, it can be viewed as a logical add-on
to the Neighbour Discovery messages such as Router Advertisement, and
as such SHOULD be treated in a similar manner.
5.8 Router Solicitation
This message uses either the unspecified address or an unicast
address as a source address. The destination address is typically a
multicast address. This message is always used only local. Since
address autoconfiguration and routing depend on the ability of the
routers and address prefixes to be found, this message is required
before any communications can be established. Therefore, this
message MUST be allowed to work independent of IKE SA establishment.
5.9 Router Advertisement
This message has always a unicast source address, but the destination
address can be either a unicast or a multicast address. Like the
solicitation message, the advertisement is also link local only and
required for establishing any communications. Therefore, this
message MUST be allowed to work independent of IKE SA establishment.
5.10 Neighbour Solicitation
The source address of this message is either a unicast address or (if
Duplicate Address Detection is in progress) the unspecified address
[6, 8]. The destination is either a multicast address, unicast
address, or an anycast address. Neighbour Solicitation and
Advertisement messages are used for multiple purposes: address
autoconfiguration, duplicate address detection, and reachability
detection. In all these roles they act only locally on the link, and
getting them through is required before any communications can be
established. Therefore, this message MUST be allowed to work
independent of IKE SA establishment.
5.11 Neighbour Advertisement
The source address of this message is a unicast address, and the
Arkko Expires September 1, 2003 [Page 12]
Internet-Draft ICMPv6 and IKE March 2003
destination is either a unicast or a multicast address. Like the
solication message, this message is link local only and is required
before any communications can be established. Therefore, this
message MUST be allowed to work independent of IKE SA establishment.
5.12 Router Renumbering
These messages are sent from a unicast address to either a multicast
or a unicast address. The message are not solely link local, they
are used for end-to-end purposes such as having a central management
station renumber all routers in a corporate network. As a result of
the RR procedure, automatically configured addresses and prefixes may
be changed. However, it is expected that a transition period exists
where both addresses are still acceptable, making it possible to
still proceed with IKE negotiations to create SAs for the RR
procedure. We can therefore assume that the procedure MAY use manual
or dynamic SAs as desired by the system administrators.
Arkko Expires September 1, 2003 [Page 13]
Internet-Draft ICMPv6 and IKE March 2003
6. Summary
Based on the above, the ICMPv6 messages can be classified as follows:
+-------------------+------------+-----------------+
| MESSAGE | ROLE | USE IKE? |
+-------------------+------------+-----------------+
| Dest Unreachable | Any-to-End | MAY(1,2) |
+-------------------+------------+-----------------+
| Packet Too Big | Any-to-End | MAY(1,3) |
+-------------------+------------+-----------------+
| Time Exceeded | Any-to-End | MAY(1,3) |
+-------------------+------------+-----------------+
| Parameter Problem | End-to-End | MAY(4) |
+-------------------+------------+-----------------+
| Echo Request | End-to-End | MAY(4) |
+-------------------+------------+-----------------+
| Echo Reply | End-to-End | MAY(4) |
+-------------------+------------+-----------------+
| Redirect | Link Local | SHOULD NOT(5) |
+-------------------+------------+-----------------+
| Router Solicit | Link Local | MUST NOT(6) |
+-------------------+------------+-----------------+
| Router Advert | Link Local | MUST NOT(6) |
+-------------------+------------+-----------------+
| Neighbour Solicit | Link Local | MUST NOT(6) |
+-------------------+------------+-----------------+
| Neighbour Advert | Link Local | MUST NOT(6) |
+-------------------+------------+-----------------+
| Router Renumbering| End-to-End | MAY(4) |
+-------------------+------------+-----------------+
Explanations:
(1) These error messages have an end-to-end nature but may be
generated by intermediate routers as well.
(2) This MAY have to be considered by implementations that wish to
base failover decisions on the Unreachable message.
(3) These messages have an impact on the success of IKE messages e.g.
when certificates are passed in IKE packets. It MUST be possible
for policies to be configured so that these messages can be
received while the IKE negotiations are still ongoing. Different
security policy configurations MUST be supported, including
trusting cleartext messages or protecting the messages from
intermediate nodes using other, new dynamic SA negotiations.
Arkko Expires September 1, 2003 [Page 14]
Internet-Draft ICMPv6 and IKE March 2003
(4) These messages MAY be treated using regular IPsec and/or IKE
processing.
(5) This message SHOULD NOT use IKE in order to make their treatment
equal with the rest of the link local messages, but in theory
Redirect MAY be handled differently, e.g. using dynamic SAs.
(6) These messages MUST NOT use dynamic SAs.
These policy rules may be expressed in various ways on a particular
host or a router. It is necessary to use the ICMPv6 type in making
the policy decisions. As [9] states, "This is consistent with,
although not mentioned by, the Security Architecture specification".
Only the following requirement for all implementations is stated
here. Products that provide hardcoded security policies for ICMPv6
messages SHOULD enable user specified policies to be expressed at a
higher priority level so that a possibility is still retained for
modifying the rules due to e.g. interoperability problems.
Arkko Expires September 1, 2003 [Page 15]
Internet-Draft ICMPv6 and IKE March 2003
7. Further Work
This draft discusses the use of IPsec on ICMPv6 messages on a
principle level. It does not take a stand on how the policies are
expressed, for instance whether IPsec products need to have hardcoded
rules for handling these messages, or whether the Security Policy
Databases should be general enough to make it possible to express the
policies in them even for the ICMPv6 messages.
This draft does not address stateful address autoconfiguration
aspects of IPv6.
This draft does not address the use of dynamic security associations
in the context of multicast traffic. Now that the multicast key
management working group has been founded in the IETF, a question
eventually arises whether or not the results of that work can be used
to protect the infrastructure multicast messages.
Arkko Expires September 1, 2003 [Page 16]
Internet-Draft ICMPv6 and IKE March 2003
Normative References
[1] McCann, J., Deering, S. and J. Mogul, "Path MTU Discovery for
IP version 6", RFC 1981, August 1996.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[3] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 2373, July 1998.
[4] Kent, S. and R. Atkinson, "Security Architecture for the
Internet Protocol", RFC 2401, November 1998.
[5] Harkins, D. and D. Carrel, "The Internet Key Exchange (IKE)",
RFC 2409, November 1998.
[6] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery
for IP Version 6 (IPv6)", RFC 2461, December 1998.
[7] Thomson, S. and T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 2462, December 1998.
[8] Conta, A. and S. Deering, "Internet Control Message Protocol
(ICMPv6) for the Internet Protocol Version 6 (IPv6)
Specification", RFC 2463, December 1998.
[9] Crawford, M., "Router Renumbering for IPv6", RFC 2894, August
2000.
[10] Narten, T. and R. Draves, "Privacy Extensions for Stateless
Address Autoconfiguration in IPv6", RFC 3041, January 2001.
Arkko Expires September 1, 2003 [Page 17]
Internet-Draft ICMPv6 and IKE March 2003
Informative References
[11] Arkko, J., Kempf, J., Sommerfeld, B. and B. Zill, "SEcure
Neighbor Discovery (SEND) Protocol",
draft-ietf-send-ipsec-00.txt (work in progress), February 2003.
[12] Nikander, P., "IPv6 Neighbor Discovery trust models and
threats", draft-ietf-send-psreq-00 (work in progress), October
2002.
[13] Arkko, J., "Manual SA Configuration for IPv6 Link Local
Messages", draft-arkko-manual-icmpv6-sas-01 (work in progress),
June 2002.
[14] Nikander, P., "Denial-of-Service, Address Ownership, and Early
Authentication in the IPv6 World", Proceedings of the Cambridge
Security Protocols Workshop, April 2001.
Author's Address
Jari Arkko
Ericsson
Jorvas 02420
Finland
EMail: jari.arkko@ericsson.com
Arkko Expires September 1, 2003 [Page 18]
Internet-Draft ICMPv6 and IKE March 2003
Appendix A. Acknowledgements
The author would like to thank Pekka Nikander, Markku Rossi, Tero
Kivinen, Michael Richardson, Erik Nordmark, and James Kempf for
interesting discussions in this problem space.
Arkko Expires September 1, 2003 [Page 19]
Internet-Draft ICMPv6 and IKE March 2003
Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances of
licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive
Director.
Full Copyright Statement
Copyright (C) The Internet Society (2003). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assignees.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
Arkko Expires September 1, 2003 [Page 20]
Internet-Draft ICMPv6 and IKE March 2003
HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
Arkko Expires September 1, 2003 [Page 21]