Network Working Group S. Daniel Park
Internet-Draft SAMSUNG Electronics
Expires : June 2004 A.K. Vijayabhaskar
Hewlett-Packard
December 2003
Configured Tunnel End Point Option for DHCPv6
draft-daniel-dhc-dhcpv6-ctep-opt-01.txt
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Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved.
Abstract
For the newly deployed IPv6 networks to interoperate with vastly
deployed IPv4 networks, various transition mechanisms had been
proposed. One such mechanism is configured tunnels. This document
provides a mechanism by which the DHCPv6 servers can provide
information about the various configured tunnel end points to reach
the IPv6 nodes which are separated by IPv4 networks.
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1. Introduction
In the initial deployment of IPv6, the IPv6 nodes may need to
communicate with the other IPv6 nodes via IPv4 networks. Configured
tunnels [3] provide a way to encapsulate the IPv6 packets in IPv4
packets and tunnel them in the IPv4 network.
This document defines a new option called Configured Tunnel End
Point by which the DHCPv6 [1] server can notify the client with the
list of end point of the configured tunnels to the various IPv6
networks separated by the IPv4 networks.
2. Requirements
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
document, are to be interpreted as described in RFC 2119 [2]
3. Terminology
This document uses terminology specific to IPv6 and DHCPv6 as
defined in "Terminology" section of the DHCPv6 specification [1].
4. Configured Tunnel End Point Option
The Configured Tunnel End Point Option gives the information to the
clients about the Configured Tunnel End Point [3] to be contacted
for reaching the nodes in the various IPv6 networks which are
separated by IPv4 networks. The clients are expected to install
these routes in their machines.
The format of the Configured Tunnel End Point Option is as shown
below:
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_CTEP | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| prefix-len | |
+-+-+-+-+-+-+-+-+-+ |
| |
| Destination Prefix (16 bytes) |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+ |
| Configured TEP Address (16 bytes) |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | prefix-len | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Destination Prefix (16 bytes) |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Configured TEP Address (16 bytes) |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| . . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code: OPTION_CTEP (TBD)
option-len: Total length of the prefix-len, Destination Prefix and
Configured Tunnel Address lists in octets; It should be
a multiple of 33.
prefix-len: prefix length of the Destination Prefix
Destination Prefix: IPv6 Prefix;
Configured TEP Address: IPv6 Address of the Configured TEP.
The clients are expected to install the routes identified by the
tuples <Destination Prefix/prefix-len, Configured TEP Address> once
they receive this option from the server.
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5. Appearance of this option
The Configured Tunnel End Point Option MUST NOT appear in other
than the following messages: Solicit, Advertise, Request, Renew,
Rebind, Information-Request and Reply.
The option numbers of Configured Tunnel End Point option MAY appear
in the Option Request Option [1] in the following messages: Solicit,
Request, Renew, Rebind, Information-Request and Reconfigure.
6. Security Considerations
The Configured Tunnel End Point Option may be used by an intruder
DHCPv6 server to provide invalid or incorrect configured tunnel end
point. This makes the client unable to reach its destination IPv6
node or to reach incorrect destination. The latter one has very
severe security issues as IPv6 destination is spoofed here.
To avoid attacks through this option, the DHCPv6 client SHOULD use
authenticated DHCP (see section "Authentication of DHCP messages" in
the DHCPv6 specification [1]).
7. IANA Considerations
IANA is requested to assign an option code to the following options
from the option-code space defined in "DHCPv6 Options" section of
the DHCPv6 specification [1].
Option Name Value Described in
OPTION_CTEP TBD Section 4
8. References
8.1 Normative References
[1] Bound, J., Carney, M., Perkins, C., Lemon, T., Volz, B. and
R.Droms (ed.), "Dynamic Host Configuration Protocol for IPv6
(DHCPv6)", RFC 3315, July 2003.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
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8.2 Informative References
[3] R. Gilligan, E. Nordmark, "Transition Mechanisms for IPv6
Hosts and Routers", RFC 2893, August 2000.
9. Authors' Addresses
Soohong Daniel Park
Mobile Platform Laboratory, SAMSUNG Electronics.
416. Maetan-Dong, Paldal-Gu,
Suwon, Gyeonggi-Do
Korea
Phone: +81-31-200-4508
E-Mail: soohong.park@samsung.com
Vijayabhaskar A K
Hewlett-Packard STSD-I
29, Cunningham Road
Bangalore - 560052
India
Phone: +91-80-2053085
E-Mail: vijayak@india.hp.com
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society. Thanks to the DHC Working Group for their time
and input into the specification. In particular, thanks to Pekka
Savola, Bernie Volz, Ralph Droms, for their valuable comments on
this work.
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