draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-04.txt   draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-05.txt 
Network Working Group G. Halwasia Network Working Group G. Halwasia
Internet-Draft S. Bhandari Internet-Draft S. Bhandari
Intended status: Standards Track W. Dec Intended status: Standards Track W. Dec
Expires: June 17, 2013 Cisco Systems Expires: September 12, 2013 Cisco Systems
December 14, 2012 March 11, 2013
Client Link-layer Address Option in DHCPv6 Client Link-layer Address Option in DHCPv6
draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-04 draft-ietf-dhc-dhcpv6-client-link-layer-addr-opt-05
Abstract Abstract
This document specifies the format and mechanism that is to be used This document specifies the format and mechanism that is to be used
for encoding client link-layer address in DHCPv6 Relay-Forward for encoding client link-layer address in DHCPv6 Relay-Forward
messages by defining a new DHCPv6 Client Link-layer Address option. messages by defining a new DHCPv6 Client Link-layer Address option.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
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
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 June 17, 2013. This Internet-Draft will expire on September 12, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2013 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
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publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Problem Background and Scenario . . . . . . . . . . . . . . . . 3 2. Problem Background and Scenario . . . . . . . . . . . . . . . 2
3. DHCPv6 Client Link-layer Address Option . . . . . . . . . . . . 4 3. DHCPv6 Client Link-layer Address Option . . . . . . . . . . . 3
4. DHCPv6 Relay Agent Behavior . . . . . . . . . . . . . . . . . . 4 4. DHCPv6 Relay Agent Behavior . . . . . . . . . . . . . . . . . 4
5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 5 5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 6. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 8. Security Considerations . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . . 6 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . . 6 10.1. Normative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 10.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
This specification defines an optional mechanism and the related This specification defines an optional mechanism and the related
DHCPv6 option to allow first-hop DHCPv6 relay agents (relay agents DHCPv6 option to allow first-hop DHCPv6 relay agents (relay agents
that are connected to the same link as the client) to provide the that are connected to the same link as the client) to provide the
client's link-layer address in the DHCPv6 messages being sent towards client's link-layer address in the DHCPv6 messages being sent towards
the server. the server.
2. Problem Background and Scenario 2. Problem Background and Scenario
skipping to change at page 4, line 4 skipping to change at page 3, line 25
existing DHCPv4 system with the client link-layer address as the existing DHCPv4 system with the client link-layer address as the
customer identifier, and desires to correlate DHCPv6 assignments customer identifier, and desires to correlate DHCPv6 assignments
using the same identifier. [RFC4361] describes a mechanism for using using the same identifier. [RFC4361] describes a mechanism for using
the same DUID in both DHCPv4 and DHCPv6. Unfortunately, this the same DUID in both DHCPv4 and DHCPv6. Unfortunately, this
specification requires modification of existing DHCPv4 clients, and specification requires modification of existing DHCPv4 clients, and
has not seen broad adoption in the industry (indeed, we are not aware has not seen broad adoption in the industry (indeed, we are not aware
of any commercial implementations). of any commercial implementations).
Providing an option in DHCPv6 Relay-Forward messages to carry client Providing an option in DHCPv6 Relay-Forward messages to carry client
link-layer address explicitly will help above mentioned scenarios. link-layer address explicitly will help above mentioned scenarios.
For example, it can be used along with other identifiers to associate
For e.g. it can be used along with other identifiers to associate
DHCPv4 and DHCPv6 messages from a dual stack client. Further, having DHCPv4 and DHCPv6 messages from a dual stack client. Further, having
client link-layer address in DHCPv6 will help in proving additional client link-layer address in DHCPv6 will help in proving additional
information in event debugging and logging related to the client at information in event debugging and logging related to the client at
relay and server. The proposed option may be used in wide range of relay and server. The proposed option may be used in wide range of
networks, two notable deployment models are service provider and networks, two notable deployment models are service provider and
enterprise network environments. enterprise network environments.
3. DHCPv6 Client Link-layer Address Option 3. DHCPv6 Client Link-layer Address Option
The format of the DHCPv6 Client Link-layer Address option is shown The format of the DHCPv6 Client Link-layer Address option is shown
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5. DHCPv6 Server Behavior 5. DHCPv6 Server Behavior
If DHCPv6 Server is configured to store or use client link-layer If DHCPv6 Server is configured to store or use client link-layer
address, it SHOULD look for the client link-layer address option in address, it SHOULD look for the client link-layer address option in
the Relay-Forward DHCP message of the DHCPv6 Relay agent closest to the Relay-Forward DHCP message of the DHCPv6 Relay agent closest to
the client. The mechanism described in this document is not the client. The mechanism described in this document is not
necessary in the case where the DHCPv6 Server is connected to the necessary in the case where the DHCPv6 Server is connected to the
same network link as the client, because the server can obtain the same network link as the client, because the server can obtain the
link-layer address from the link-layer header of the DHCPv6 message. link-layer address from the link-layer header of the DHCPv6 message.
If the DHCP server receives a Client Link-layer Address option
anywhere in any encapsulated message that is not a Relay-Forward DHCP
message, the server MUST silently ignore that option.
There is no requirement that a server return this option and its data There is no requirement that a server return this option and its data
in a downstream DHCP message. in a downstream DHCP message.
6. IANA Considerations 6. DHCPv6 Client Behavior
Client Link-layer Address option is only exchanged between the relay
agents and the servers. DHCPv6 clients are not aware of the usage of
Client Link-layer Address option. DHCPv6 client MUST NOT send Client
Link-layer Address option, and MUST ignore Client Link-layer Address
option if received.
7. IANA Considerations
IANA is requested to assign an option code to IANA is requested to assign an option code to
OPTION_CLIENT_LINKLAYER_ADDR from the "DHCP Option Codes" registry OPTION_CLIENT_LINKLAYER_ADDR from the "DHCP Option Codes" registry
(http://www.iana.org/assignments/dhcpv6-parameters/dhcpv6- (http://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-
parameters.xml). parameters.xml).
7. Security Considerations 8. Security Considerations
It is possible for a rogue DHCPv6 relay agent to insert an incorrect It is possible for a rogue DHCPv6 relay agent to insert an incorrect
Client Link Layer Address option for malicious purposes. A DHCPv6 Client Link Layer Address option for malicious purposes. A DHCPv6
client can also pose as a rogue DHCP relay agent, sending a Relay- client can also pose as a rogue DHCP relay agent, sending a Relay-
Forward message containing an incorrect Client Link Layer Address Forward message containing an incorrect Client Link Layer Address
option. In either case, it would be possible for a DHCPv6 client to option. In either case, it would be possible for a DHCPv6 client to
masquerade as the same device as a DHCPv4 client, when in fact the masquerade as the same device as a DHCPv4 client, when in fact the
two are distinct. two are distinct.
One possible attack that could be accomplished using this masquerade One possible attack that could be accomplished using this masquerade
skipping to change at page 6, line 5 skipping to change at page 5, line 45
stack nodes attempting to connect to the DHCPv4 client might then be stack nodes attempting to connect to the DHCPv4 client might then be
tricked into connecting to the masquerading DHCPv6 client instead. tricked into connecting to the masquerading DHCPv6 client instead.
It is possible that there are other attacks that could be It is possible that there are other attacks that could be
accomplished using this masquerading technique, although the authors accomplished using this masquerading technique, although the authors
are not aware of any. To prevent masquerades of this sort, DHCP are not aware of any. To prevent masquerades of this sort, DHCP
server administrators are strongly advised to configure DHCP servers server administrators are strongly advised to configure DHCP servers
that use this option to communicate with their relay agents using that use this option to communicate with their relay agents using
IPsec as described in Section 21.1 of [RFC3315]. IPsec as described in Section 21.1 of [RFC3315].
8. Acknowledgements In some networks, it may be the case that the operator of the
physical network and the provider of connectivity over that network
are administratively separate, such that the client link-layer
address option would reveal information to one or the other party
that they do not need and could not otherwise obtain. It is also
possible in some cases that a relay agent might communicate with a
DHCP server over an open network where eavesdropping would be
possible. In these cases, it is strongly recommended, in order to
protect end-user privacy, that network operators use IPsec to provide
confidentiality for messages between the relay agent and DHCP server.
9. Acknowledgements
Many thanks to Ted Lemon, Bernie Volz, Hemant Singh, Simon Hobson, Many thanks to Ted Lemon, Bernie Volz, Hemant Singh, Simon Hobson,
Tina TSOU, Andre Kostur, Chuck Anderson, Steinar Haug, Niall Tina TSOU, Andre Kostur, Chuck Anderson, Steinar Haug, Niall
O'Reilly, Jarrod Johnson, Tomek Mrugalski and Vincent Zimmer for O'Reilly, Jarrod Johnson, Tomek Mrugalski and Vincent Zimmer for
their input and review. their input and review.
9. References 10. References
9.1. Normative References 10.1. Normative References
[RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or [RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or
converting network protocol addresses to 48.bit Ethernet converting network protocol addresses to 48.bit Ethernet
address for transmission on Ethernet hardware", STD 37, address for transmission on Ethernet hardware", STD 37,
RFC 826, November 1982. RFC 826, November 1982.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003. IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC4361] Lemon, T. and B. Sommerfeld, "Node-specific Client [RFC4361] Lemon, T. and B. Sommerfeld, "Node-specific Client
Identifiers for Dynamic Host Configuration Protocol Identifiers for Dynamic Host Configuration Protocol
Version Four (DHCPv4)", RFC 4361, February 2006. Version Four (DHCPv4)", RFC 4361, February 2006.
9.2. Informative References 10.2. Informative References
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
RFC 2131, March 1997. 2131, March 1997.
[RFC4702] Stapp, M., Volz, B., and Y. Rekhter, "The Dynamic Host [RFC4702] Stapp, M., Volz, B., and Y. Rekhter, "The Dynamic Host
Configuration Protocol (DHCP) Client Fully Qualified Configuration Protocol (DHCP) Client Fully Qualified
Domain Name (FQDN) Option", RFC 4702, October 2006. Domain Name (FQDN) Option", RFC 4702, October 2006.
[RFC4704] Volz, B., "The Dynamic Host Configuration Protocol for [RFC4704] Volz, B., "The Dynamic Host Configuration Protocol for
IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN) IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN)
Option", RFC 4704, October 2006. Option", RFC 4704, October 2006.
Authors' Addresses Authors' Addresses
Gaurav Halwasia Gaurav Halwasia
Cisco Systems Cisco Systems
Cessna Business Park, Sarjapura Marathalli Outer Ring Road Cessna Business Park, Sarjapura Marathalli Outer Ring Road
Bangalore, KARNATAKA 560 087 Bangalore, KARNATAKA 560 087
India India
Phone: +91 80 4426 1321 Phone: +91 80 4429 2703
Email: ghalwasi@cisco.com Email: ghalwasi@cisco.com
Shwetha Bhandari Shwetha Bhandari
Cisco Systems Cisco Systems
Cessna Business Park, Sarjapura Marathalli Outer Ring Road Cessna Business Park, Sarjapura Marathalli Outer Ring Road
Bangalore, KARNATAKA 560 087 Bangalore, KARNATAKA 560 087
India India
Phone: +91 80 4426 0474 Phone: +91 80 4429 2627
Email: shwethab@cisco.com Email: shwethab@cisco.com
Wojciech Dec Wojciech Dec
Cisco Systems Cisco Systems
Haarlerbergweg 13-19 Haarlerbergweg 13-19
1101 CH Amsterdam, Amsterdam 560 087 1101 CH Amsterdam, Amsterdam 560 087
The Netherlands The Netherlands
Email: wdec@cisco.com Email: wdec@cisco.com
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