draft-ietf-dhc-vendor-suboption-00.txt   rfc4243.txt 
DHC Working Group M. Stapp Network Working Group M. Stapp
Internet-Draft R. Johnson Request for Comments: 4243 R. Johnson
Expires: February 7, 2005 T. Palaniappan Category: Standards Track T. Palaniappan
Cisco Systems, Inc. Cisco Systems, Inc.
August 9, 2004 December 2005
Vendor-Specific Information Suboption for the DHCP Relay Agent Option
<draft-ietf-dhc-vendor-suboption-00.txt>
Status of this Memo
By submitting this Internet-Draft, I certify that any applicable
patent or other IPR claims of which I am aware have been disclosed,
and any of which I become aware will be disclosed, in accordance with
RFC 3667.
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:// Vendor-Specific Information Suboption for the
www.ietf.org/ietf/1id-abstracts.txt. Dynamic Host Configuration Protocol (DHCP) Relay Agent Option
The list of Internet-Draft Shadow Directories can be accessed at Status of This Memo
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on February 7, 2005. This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved. Copyright (C) The Internet Society (2005).
Abstract Abstract
This memo defines a new Vendor-Specific Information suboption for the This memo defines a new Vendor-Specific Information suboption for the
Dynamic Host Configuration Protocol's (DHCP) relay agent information Dynamic Host Configuration Protocol's (DHCP) relay agent information
option. The suboption allows a DHCP relay agent to include option. The suboption allows a DHCP relay agent to include vendor-
vendor-specific information in DHCP messages it forwards, as specific information in the DHCP messages it forwards, as configured
configured by its administrator. by its administrator.
Table of Contents Table of Contents
1. Requirements Terminology . . . . . . . . . . . . . . . . . . . . 3 1. Introduction ....................................................2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Terminology ........................................2
3. The Vendor-Specific Suboption . . . . . . . . . . . . . . . . . 3 3. The Vendor-Specific Suboption ...................................2
4. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . . . 4 4. Relay Agent Behavior ............................................4
5. DHCP Server Behavior . . . . . . . . . . . . . . . . . . . . . . 5 5. DHCP Server Behavior ............................................4
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 6. Security Considerations .........................................4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 7. IANA Considerations .............................................5
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 6 8. Acknowledgements ................................................5
Normative References . . . . . . . . . . . . . . . . . . . . . . 7 Normative References ...............................................5
Informative References . . . . . . . . . . . . . . . . . . . . . 7 Informative References .............................................5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
Intellectual Property and Copyright Statements . . . . . . . . . 9
1. Requirements Terminology
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 [1].
2. Introduction 1. Introduction
DHCP (RFC 2131 [2]) provides IP addresses and configuration DHCP (RFC 2131 [2]) provides IP addresses and configuration
information for IPv4 clients. It includes a relay agent capability, information for IPv4 clients. It includes a relay agent capability,
in which processes within the network infrastructure receive in which processes within the network infrastructure receive
broadcast messages from clients and forward them to DHCP servers as broadcast messages from clients and forward them to DHCP servers as
unicast messages. In network environments like DOCSIS data-over-cable unicast messages. In network environments like DOCSIS data-over-
and xDSL, for example, it has proven useful for the relay agent to cable and xDSL, for example, it has proven useful for the relay agent
add information to the DHCP message before forwarding it, using the to add information to the DHCP message before forwarding it, using
relay agent information option (RFC 3046 [3]). the relay agent information option (RFC 3046 [3]).
Servers that recognize the relay agent option echo it back in their Servers that recognize the relay agent option echo it back in their
replies, and some of the information that relays add may be used to replies, and some of the information that relays add may be used to
help an edge device efficiently return replies to clients. The help an edge device efficiently return replies to clients. The
information that relays supply can also be used in the server's information that relays supply can also be used in the server's
decision making about the addresses and configuration parameters that decision making about the addresses and configuration parameters that
the client should receive. the client should receive.
In many environments it's desirable to associate some vendor- or In many environments, it's desirable to associate some vendor- or
provider-specific information with clients' DHCP messages. This is provider-specific information with the clients' DHCP messages. This
often done using the relay agent information option. RFC 3046 defines is often done using the relay agent information option. RFC 3046
Remote-ID and Circuit-ID sub-options that are used to carry such defines Remote-ID and Circuit-ID sub-options that are used to carry
information. The values of those suboptions, however, are usually such information. The values of those suboptions, however, are
based on some network resource, such as an IP address of a network usually based on some network resource, such as an IP address of a
access device, an ATM Virtual Circuit identifier, or a DOCSIS network access device, an ATM Virtual Circuit identifier, or a DOCSIS
cable-modem identifier. As a result, the values carried in these cable-modem identifier. As a result, the values carried in these
suboptions are dependent on the physical network configuration. The suboptions are dependent on the physical network configuration. The
Vendor-Specific suboption allows administrators to associate other Vendor-Specific suboption allows administrators to associate other
useful data with relayed DHCP messages. useful data with relayed DHCP messages.
2. Requirements Terminology
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 [1].
3. The Vendor-Specific Suboption 3. The Vendor-Specific Suboption
This memo defines a new DHCP relay agent option suboption that This memo defines a new DHCP relay agent option suboption that
carries vendor-defined data. The suboption takes a form similar to carries vendor-defined data. The suboption takes a form similar to
the Vendor-Identifying Vendor-Specific Option [8]. the Vendor-Identifying, Vendor-Specific Option [7].
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Length | Enterprise Number1 | | Code | Length | Enterprise Number1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | DataLen1 | | | | DataLen1 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
\ Suboption Data1 \ \ Suboption Data1 \
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Enterprise Number2 | | Enterprise Number2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DataLen2 | Suboption Data2 | | DataLen2 | Suboption Data2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ \ \ \
. . . .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Code for the suboption is <TBD> (to be assigned by IANA). The Code for the suboption is 9.
The one-byte Length field is the length of the data carried in the The one-byte Length field is the length of the data carried in the
suboption, in bytes. The length includes the length of the first suboption, in bytes. The length includes the length of the first
Enterprise Number; the minimum length is 4 bytes. Enterprise Number; the minimum length is 4 bytes.
"Enterprise NumberN" is a vendor's Enterprise Number as registered "Enterprise NumberN" is a vendor's Enterprise Number as registered
with IANA [4]. It is a four-byte integer value in network byte-order. with IANA [4]. It is a four-byte integer value in network byte-
order.
DataLenN is the length of the data associated with the Enterprise DataLenN is the length of the data associated with the Enterprise
Number. Number.
The Suboption Data is an opaque sequence of bytes. The Suboption Data is an opaque sequence of bytes.
The Vendor-Specific suboption includes at least one Enterprise Number The Vendor-Specific suboption includes at least one Enterprise Number
and carries opaque data defined by the organization identified by the and carries opaque data defined by the organization identified by the
Enterprise Number. A relay may include data associated with more than Enterprise Number. A relay may include data associated with more
one vendor's Enterprise Number within a single instance of the than one vendor's Enterprise Number within a single instance of the
Suboption. Suboption.
The Vendor-Specific data are of course provider-specific. This Of course, the Vendor-Specific data are vendor-specific. This
specification does not establish any requirements on the data in the specification does not establish any requirements on the data in the
suboption. Vendors who make use of this suboption are encouraged to suboption. Vendors who make use of this suboption are encouraged to
document their usage in order to make interoperability possible. document their usage in order to make interoperability possible.
4. Relay Agent Behavior 4. Relay Agent Behavior
DHCP relay agents MAY be configured to include Vendor-Specific DHCP relay agents MAY be configured to include Vendor-Specific
suboptions if they include a relay agent information option in suboptions if they include a relay agent information option in
relayed DHCP messages. The suboptions' types and data are assigned relayed DHCP messages. The suboptions' types and data are assigned
and configured through mechanisms that are outside the scope of this and configured through mechanisms that are outside the scope of this
memo. memo.
Relay implementors are encouraged to offer their administrators some Relay implementors are encouraged to offer their administrators a
means of configuring what data can be included in this suboption, and means of configuring what data can be included in this suboption, and
to document what they are capable of. to document what they are capable of.
5. DHCP Server Behavior 5. DHCP Server Behavior
This suboption provides additional information to the DHCP server. This suboption provides additional information to the DHCP server.
The DHCP server, if it is configured to support this suboption, may The DHCP server, if it is configured to support this suboption, may
use this information in addition to other relay agent option data and use this information, in addition to other relay agent option data
other options included in the DHCP client messages in order to assign and other options included in the DHCP client messages, in order to
an IP address and/or other configuration parameters to the client. assign an IP address and/or other configuration parameters to the
There is no special additional processing for this suboption. client. There is no special additional processing for this
suboption.
DHCP server vendors are encouraged to offer their administrators some
means of configuring the use of data from incoming Vendor-Specific
suboptions in DHCP decision-making.
6. Security Considerations 6. Security Considerations
Message authentication in DHCP for intradomain use where the Message authentication in DHCP for intradomain use, where the out-
out-of-band exchange of a shared secret is feasible is defined in RFC of-band exchange of a shared secret is feasible, is defined in RFC
3118 [5]. Potential exposures to attack are discussed in section 7 of 3118 [5]. Potential exposures to attack are discussed in section 7
the DHCP protocol specification in RFC 2131 [2]. of the DHCP protocol specification in RFC 2131 [2].
The DHCP relay agent option depends on a trusted relationship between The DHCP relay agent option depends on a trusted relationship between
the DHCP relay agent and the server, as described in section 5 of RFC the DHCP relay agent and the server, as described in section 5 of RFC
3046. Fraudulent relay agent option data could potentially lead to 3046. Fraudulent relay agent option data could potentially lead to
theft-of-service or exhaustion of limited resources (like IP theft-of-service or exhaustion of limited resources (like IP
addresses) by unauthorized clients. A host that tampered with relay addresses) by unauthorized clients. A host that tampered with relay
agent data associated with another host's DHCP messages could deny agent data associated with another host's DHCP messages could deny
service to that host, or interfere with its operation by leading the service to that host, or interfere with its operation by leading the
DHCP server to assign it inappropriate configuration parameters. DHCP server to assign it inappropriate configuration parameters.
While the introduction of fraudulent relay agent options can be While the introduction of fraudulent relay agent options can be
prevented by a perimeter defense that blocks these options unless the prevented by a perimeter defense that blocks these options unless the
relay agent is trusted, a deeper defense using authentication for relay agent is trusted, a deeper defense using authentication for
relay agent options via the Authentication Suboption [6] or IPSEC [7] relay agent options via the Authentication Suboption [6] SHOULD be
SHOULD be deployed as well. deployed as well.
There are several data in a DHCP message that convey information that There are several data in a DHCP message that convey information that
may identify an individual host on the network. These include the may identify an individual host on the network. These include the
chaddr, the client-id option, and the hostname and client-fqdn chaddr, the client-id option, and the hostname and client-fqdn
options. Depending on the type of data included, the Vendor-Specific options. Depending on the type of data included, the Vendor-Specific
suboption may also convey information that identifies a specific host suboption may also convey information that identifies a specific host
or a specific user on the network. In practice, this information or a specific user on the network. In practice, this information
isn't exposed outside the internal service-provider network, where isn't exposed outside the internal service-provider network, where
DHCP messages are usually confined. Administrators who configure data DHCP messages are usually confined. Administrators who configure
that's going to be used in DHCP Vendor-Specific suboptions should be data that will be used in DHCP Vendor-Specific suboptions should be
careful to use data that are appropriate for the types of networks careful to use data that are appropriate for the types of networks
they administer. If DHCP messages travel outside the they administer. If DHCP messages travel outside the service-
service-provider's own network, or if the suboption values may become provider's own network, or if the suboption values may become visible
visible to other users, that may raise privacy concerns for the to other users, it may raise privacy concerns for the access provider
access provider or service provider. or service provider.
7. IANA Considerations 7. IANA Considerations
IANA is requested to assign a suboption number for the The IANA has assigned the suboption number 9 for the Vendor-Specific
Vendor-Specific Information Suboption from the DHCP Relay Agent Information Suboption from the DHCP Relay Agent Information Option
Information Option [3] suboption number space. [3] suboption number space.
8. Acknowledgements 8. Acknowledgements
The authors are grateful to Andy Sudduth, Josh Littlefield, and Kim The authors are grateful to Andy Sudduth, Josh Littlefield, and Kim
Kinnear for their review and comments. Kinnear for their review and comments.
Normative References 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", RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, [2] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131,
March 1997. March 1997.
[3] Patrick, M., "DHCP Relay Agent Information Option", RFC 3046, [3] Patrick, M., "DHCP Relay Agent Information Option", RFC 3046,
January 2001. January 2001.
[4] IANA, "Private Enterprise Numbers (http://www.iana.org/ [4] IANA, "Private Enterprise Numbers (http://www.iana.org/
assignments/enterprise-numbers.html)". assignments/enterprise-numbers.html)".
Informative References Informative References
[5] Droms, R. and W. Arbaugh, "Authentication for DHCP Messages", [5] Droms, R. and W. Arbaugh, "Authentication for DHCP Messages",
RFC 3118, June 2001. RFC 3118, June 2001.
[6] Stapp, M., "The Authentication Suboption for the DHCP Relay [6] Stapp, M. and T. Lemon, "The Authentication Suboption for the
Agent Option", draft-ietf-dhc-auth-suboption-04.txt (work in Dynamic Host Configuration Protocol (DHCP) Relay Agent Option",
progress), October 2003. RFC 4030, March 2005.
[7] Droms, R., "Authentication of Relay Agent Options Using IPsec",
draft-ietf-dhc-relay-agent-ipsec-01.txt (work in progress),
November 2003.
[8] Littlefield, J., "Vendor-Identifying Vendor Options for DHCPv4", [7] Littlefield, J., "Vendor-Identifying Vendor Options for Dynamic
draft-ietf-dhc-vendor-03.txt (work in progress), June 2004. Host Configuration Protocol version 4 (DHCPv4)", RFC 3925,
October 2004.
Authors' Addresses Authors' Addresses
Mark Stapp Mark Stapp
Cisco Systems, Inc. Cisco Systems, Inc.
1414 Massachusetts Ave. 1414 Massachusetts Ave.
Boxborough, MA 01719 Boxborough, MA 01719
USA USA
Phone: 978.936.0000 Phone: 978.936.0000
skipping to change at page 9, line 5 skipping to change at page 7, line 5
Theyn Palaniappan Theyn Palaniappan
Cisco Systems, Inc. Cisco Systems, Inc.
170 W. Tasman Dr. 170 W. Tasman Dr.
San Jose, CA 95134 San Jose, CA 95134
USA USA
Phone: 408.526.4000 Phone: 408.526.4000
EMail: athenmoz@cisco.com EMail: athenmoz@cisco.com
Intellectual Property Statement Full Copyright Statement
Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the IETF's procedures with respect to rights in IETF Documents can on the procedures with respect to rights in RFC documents can be
be found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an 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 attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at ietf-
ietf-ipr@ietf.org. ipr@ietf.org.
Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2004). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgement
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is currently provided by the
Internet Society. Internet Society.
 End of changes. 31 change blocks. 
124 lines changed or deleted 101 lines changed or added

This html diff was produced by rfcdiff 1.28, available from http://www.levkowetz.com/ietf/tools/rfcdiff/