draft-ietf-dhc-dhcpv6-srsn-option-00.txt   draft-ietf-dhc-dhcpv6-srsn-option-01.txt 
dhc Group B. Volz dhc Group B. Volz
Internet-Draft R. Droms Internet-Draft R. Droms
Intended status: Informational Cisco Systems, Inc. Intended status: Informational Cisco Systems, Inc.
Expires: May 17, 2007 November 13, 2006 Expires: September 2, 2007 March 1, 2007
DHCPv6 Server Reply Sequence Number Option DHCPv6 Server Reply Sequence Number Option
draft-ietf-dhc-dhcpv6-srsn-option-00.txt draft-ietf-dhc-dhcpv6-srsn-option-01.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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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."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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This Internet-Draft will expire on May 17, 2007. This Internet-Draft will expire on September 2, 2007.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The IETF Trust (2007).
Abstract Abstract
This memo defines the Server Reply Sequence Number option for the This memo defines the Server Reply Sequence Number option for the
Dynamic Host Configuration Protocol for IPv6 (DHCPv6). This option Dynamic Host Configuration Protocol for IPv6 (DHCPv6). This option
is sent from a DHCPv6 server to a DHCPv6 relay agent to allow a relay is sent from a DHCPv6 server to a DHCPv6 relay agent to allow a relay
agent to detect proper sequencing of Relay-Reply messages that could agent to detect proper sequencing of Relay-Reply messages that could
be delivered out of order. be delivered out of order.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. The Server Reply Sequence Number Option . . . . . . . . . . . . 3 3. The Server Reply Sequence Number Option . . . . . . . . . . . . 3
4. DHCPv6 Relay Agent Behavior . . . . . . . . . . . . . . . . . . 4 4. DHCPv6 Relay Agent Behavior . . . . . . . . . . . . . . . . . . 4
5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 5 5. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . . 5
6. IANA considerations . . . . . . . . . . . . . . . . . . . . . . 5 6. IANA considerations . . . . . . . . . . . . . . . . . . . . . . 5
7. Security considerations . . . . . . . . . . . . . . . . . . . . 6 7. Security considerations . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 8. Modification History . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . . 6 9.1. Normative References . . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6
Intellectual Property and Copyright Statements . . . . . . . . . . 8 Intellectual Property and Copyright Statements . . . . . . . . . . 8
1. Introduction 1. Introduction
When a DHCPv6 server sends a Reply, there is no guarantee as to the When a DHCPv6 server sends a Reply, there is no guarantee as to the
order of delivery of those datagrams sent by a server. A DHCPv6 order of delivery of those datagrams sent by a server. A DHCPv6
client is protected against delivery of old Reply messages because of client is protected against delivery of old Reply messages because of
the transaction-id in the message. However, a relay agent receiving the transaction-id in the message. However, a relay agent receiving
Relay-Reply messages and maintaining client state information (e.g., Relay-Reply messages and maintaining client state information (e.g.,
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To allow a relay agent to detect and discard out of order messages, To allow a relay agent to detect and discard out of order messages,
the relay agent requests the server to include a SRSN option in the relay agent requests the server to include a SRSN option in
Relay-Reply messages. The SRSN option contains a monotonically Relay-Reply messages. The SRSN option contains a monotonically
increasing sequence number that the relay agent can use to re- increasing sequence number that the relay agent can use to re-
sequence (or discard) out of order Relay-Reply messages from the sequence (or discard) out of order Relay-Reply messages from the
server. server.
2. Terminology 2. Terminology
The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL in this document are to be "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
interpreted as described in [1]. document are to be interpreted as described in [1].
Additional terms used in the description of DHCPv6 and DHCPv6 prefix Additional terms used in the description of DHCPv6 and DHCPv6 prefix
delegation are defined in [2] and [3]. delegation are defined in [2] and [3].
3. The Server Reply Sequence Number Option 3. The Server Reply Sequence Number Option
The SRSN option is used by a server to indicate the order in which The SRSN option is used by a server to indicate the order in which
the server has generated replies and therefore allows a relay agent the server has generated replies and therefore allows a relay agent
receiving Relay-Reply messages to determine the order in which those receiving Relay-Reply messages to determine the order in which those
Relay-Reply messages were originally sent. The Relay-Reply messages Relay-Reply messages were originally sent. The Relay-Reply messages
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Security issues related to DHCP are described in [2] and [3]. Security issues related to DHCP are described in [2] and [3].
The DHCPv6 Server Reply Sequence Number option may be used to mount a The DHCPv6 Server Reply Sequence Number option may be used to mount a
denial of service attack by causing a relay agent to incorrectly denial of service attack by causing a relay agent to incorrectly
record a very high server-reply-sequence-number and thus preventing record a very high server-reply-sequence-number and thus preventing
legitimate Relay-Reply messages from a server from being processed. legitimate Relay-Reply messages from a server from being processed.
Communication between a server and a relay agent, and communication Communication between a server and a relay agent, and communication
between relay agents, can be secured through the use of IPSec, as between relay agents, can be secured through the use of IPSec, as
described in section 21.1 of [2]. described in section 21.1 of [2].
8. References 8. Modification History
8.1. Normative References Changes in rev -01 (to fix idnits):
o Revised terminology section to match recommended RFC 2119 syntax.
o Used new I-D boilerplate.
o Added this section.
9. References
9.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M. [2] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M.
Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 3315, July 2003. RFC 3315, July 2003.
[3] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host [3] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host
Configuration Protocol (DHCP) version 6", RFC 3633, Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003. December 2003.
8.2. Informative References 9.2. Informative References
[4] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, [4] Postel, J., "Transmission Control Protocol", STD 7, RFC 793,
September 1981. September 1981.
[5] Droms, R., "DHCPv6 Relay Agent Assignment Notification (RAAN) [5] Droms, R., "DHCPv6 Relay Agent Assignment Notification (RAAN)
Option", draft-ietf-dhc-dhcpv6-agentopt-delegate-02 (work in Option", draft-ietf-dhc-dhcpv6-agentopt-delegate-02 (work in
progress), November 2006. progress), November 2006.
Authors' Addresses Authors' Addresses
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Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Avenue 1414 Massachusetts Avenue
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Phone: +1 978.936.1674 Phone: +1 978.936.1674
Email: rdroms@cisco.com Email: rdroms@cisco.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2006). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
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INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
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Intellectual Property Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
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made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
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