draft-ietf-dhc-problem-statement-of-mredhcpv6-00.txt   draft-ietf-dhc-problem-statement-of-mredhcpv6-01.txt 
Dynamic Host Configuration (DHC) G. Ren Dynamic Host Configuration (DHC) G. Ren
Internet-Draft L. He Internet-Draft L. He
Intended status: Informational Y. Liu Intended status: Informational Y. Liu
Expires: November 24, 2019 Tsinghua University Expires: April 13, 2020 Tsinghua University
May 23, 2019 October 11, 2019
Problem Statement of Multi-requirement Extensions for Dynamic Host Problem Statement of Multi-requirement Extensions for Dynamic Host
Configuration Protocol for IPv6 (DHCPv6) Configuration Protocol for IPv6 (DHCPv6)
draft-ietf-dhc-problem-statement-of-mredhcpv6-00 draft-ietf-dhc-problem-statement-of-mredhcpv6-01
Abstract Abstract
The manageability, security, privacy protection, and traceability of The manageability, security, privacy protection, and traceability of
networks can be supported by extending DHCPv6 protocol according to networks can be supported by extending DHCPv6 protocol according to
requirements. This document analyzes current extension practices and requirements. This document analyzes current extension practices and
typical DHCP server software on extensions, defines a DHCP general typical DHCP server software on extensions, defines a DHCP general
model, discusses some extension points, and present extension cases. model, discusses some extension points, and present extension cases.
Status of This Memo Status of This Memo
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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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://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 November 24, 2019. This Internet-Draft will expire on April 13, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 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
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Current Extension Practices . . . . . . . . . . . . . . . . . 3 3. Current Extension Practices . . . . . . . . . . . . . . . . . 3
3.1. Standardized and Non-standardized DHCPv6 Extension Cases 3 3.1. Standardized and Non-standardized DHCPv6 Extension Cases 3
3.2. Current DHCPv6 Server Software Cases . . . . . . . . . . 4 3.2. Current DHCPv6 Server Software Cases . . . . . . . . . . 4
3.2.1. Cisco Prime Network Registrar DHCP Server Extension 3.2.1. Cisco Prime Network Registrar DHCP Server Extension
APIs . . . . . . . . . . . . . . . . . . . . . . . . 4 APIs . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2.2. Kea DHCP Hook Mechanisms . . . . . . . . . . . . . . 4 3.2.2. Kea DHCP Hook Mechanisms . . . . . . . . . . . . . . 4
4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5 4. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5
4.1. DHCP General Model . . . . . . . . . . . . . . . . . . . 5 4.1. DHCP General Model . . . . . . . . . . . . . . . . . . . 5
4.2. Extension Discussion . . . . . . . . . . . . . . . . . . 5 4.2. Extension Discussion . . . . . . . . . . . . . . . . . . 5
4.2.1. DHCP Messages . . . . . . . . . . . . . . . . . . . . 5 4.2.1. Messages . . . . . . . . . . . . . . . . . . . . . . 5
4.2.2. Options . . . . . . . . . . . . . . . . . . . . . . . 6 4.2.2. Options . . . . . . . . . . . . . . . . . . . . . . . 6
4.2.3. Message Processing Functions . . . . . . . . . . . . 6 4.2.3. Message Processing Functions . . . . . . . . . . . . 6
4.2.4. Address Generation Mechanisms . . . . . . . . . . . . 6 4.2.4. Address Generation Mechanisms . . . . . . . . . . . . 7
4.2.5. Extension Principles . . . . . . . . . . . . . . . . 7
5. Extension Cases . . . . . . . . . . . . . . . . . . . . . . . 7 5. Extension Cases . . . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
9. Normative References . . . . . . . . . . . . . . . . . . . . 8 9. Normative References . . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
The IP address plays a significant role in the communication of the The IP address plays a significant role in the communication of the
Internet. IP address generation is also closely related to the Internet. IP address generation is also closely related to the
manageability, security, privacy protection, and traceability of manageability, security, privacy protection, and traceability of
networks. Dynamic Host Configuration Protocol for IPv6 (DHCPv6) networks. Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
[RFC8415] is an important network protocol that can be used to [RFC8415] is an important network protocol that can be used to
dynamically provide IPv6 addresses and other network configuration dynamically provide IPv6 addresses and other network configuration
parameters to IPv6 nodes. Actually, DHCPv6 continues to be extended parameters to IPv6 nodes. Actually, DHCPv6 continues to be extended
and improved through new options, protocols or message processing and improved through new options, protocols or message processing
mechanisms. mechanisms.
Although DHCPv6 provides more and more comprehensive functionalities Although DHCPv6 provides more and more comprehensive functionalities
and DHCPv6 server software also provides extension interfaces to and DHCPv6 server software also provides extension interfaces to
allow administrators to alter and customize the way how they handle allow administrators to alter and customize the way how they handle
and respond to DHCPv6 messages, there is still a lack of a general and respond to DHCPv6 messages, there is still a lack of a general
insight into where and how to conduct extensions in DHCPv6 insight into where and how to conduct extensions in DHCPv6
effectively. The extensions to DHCPv6 can be various according to effectively. The extensions to DHCPv6 can be various according to
multiple requirements. Therefore, a detailed analysis is required to multiple requirements. The goal of multi-requirement extensions for
clarify the problems, design principles, and extract and unify the DHCPv6 is to use simple interfaces to define and support more
design specifications to help better solve the multi-requirement extensions without changing the basic design of DHCPv6. Therefore, a
extension problems. detailed analysis is required to clarify the problems, design
principles, and extract and unify the design specifications to help
better solve the multi-requirement extension problems.
In summary, multi-requirement extensions for DHCPv6 can be conducted In summary, multi-requirement extensions for DHCPv6 can be conducted
to support the administrator's self-defined functionalities. As to support the administrator's self-defined functionalities. As
DHCPv6 is an important and useful protocol related to IPv6 addresses DHCPv6 is an important and useful protocol related to IPv6 addresses
generation, it can provide more extended and flexible functionalities generation, it can provide more extended and flexible functionalities
to meet administrators' requirements. According to well-designed to meet administrators' requirements. According to well-designed
principles, extended interfaces can be defined to support more self- principles, extended interfaces can be defined to support more self-
defined multi-requirement extensions without sacrificing the defined multi-requirement extensions without sacrificing the
stability of DHCPv6. stability of DHCPv6.
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4. Problem Statement 4. Problem Statement
This section elaborates the problem statement of multi-requirement This section elaborates the problem statement of multi-requirement
extensions for DHCPv6. Section 4.1 describes the general model of extensions for DHCPv6. Section 4.1 describes the general model of
DHCP, while Section 4.2 analyzes the extension points and DHCP, while Section 4.2 analyzes the extension points and
requirements, suggesting possible future work. requirements, suggesting possible future work.
4.1. DHCP General Model 4.1. DHCP General Model
Figure 1 summarizes the DHCP general model and its possible Figure 1 summarizes the DHCP general model and its possible
extensions: DHCP messages, options, message processing functions, and extensions: messages, options, message processing functions, and
address generation mechanisms. address generation mechanisms.
+-------------------+ +------------------+ +-----------------+ +----------------+
| DHCPv6 client | | DHCPv6 relay | | DHCPv6 client | DHCP messages | DHCPv6 relay |
| +---------------+ | DHCP messages with options| +--------------+ | | +-------------+ | with options | +------------+ | External inputs
| | Message | |<------------------------->| | Message | | | | Message | |<----------------->| | Message | |<----------------
| | processing | | | | relaying | | | | processing | | | | relaying | | e.g., RADIUS
| | functions | | | | functions | | | | functions | | | | functions | | option [RFC7037]
| +---------------+ | | +--------------+ | | +-------------+ | | +------------+ |
+-------------------+ +------------------+ +-----------------+ +----------------+
^ ^
| DHCP messages |
DHCP messages with options | with options |
| |
V V
+------------------+ +-----------------+ +----------------------------+
| DHCPv6 server | | | Extended | DHCPv6 server |
+------------+ | +--------------+ | | | messages | +-----------+ +----------+ |
| Address | | | Message | | |External entities|<------------->| | Address | | Message | |
| generation |<-----------------------------+-| processing | | | | e.g., Active | | generation| |processing| |
| mechanisms | | | functions | | | | leasequery | | mechanisms| |functions | |
+------------+ | +--------------+ | | | [RFC7653] | +-----------+ +----------+ |
+------------------+ +-----------------+ +----------------------------+
Figure 1: DHCP general model and its possible extensions. Figure 1: DHCP general model and its possible extensions.
4.2. Extension Discussion 4.2. Extension Discussion
4.2.1. DHCP Messages 4.2.1. Messages
In fact, new messages can be designed and added to DHCPv6 protocol, On the one hand, new DHCP messages can be designed and added to
e.g., active leasequery [RFC7653]. But currently, people are DHCPv6 protocol to enrich its funtionalities. For example, [RFC5007]
concerned about the security and privacy issues of DHCP protocol. defines new leasequery messages to allow a requestor to retrive
[RFC7819] and [RFC7824] describe the privacy issues associated with information on the bindings for a client from one or more servers.
the use of DHCPv4 and DHCPv6, respectively. DHCPv6 does not provide
the privacy protection on messages and options. That is to say, [RFC7653] defines active leasequery messages to keep the requestor up
other nodes can see the options transmitted in the DHCPv6 messages to date with DHCPv6 bindings.
between DHCPv6 clients and servers.
On the other hand, people are concerned about the security and
privacy issues of DHCP protocol. [RFC7819] and [RFC7824] describe
the privacy issues associated with the use of DHCPv4 and DHCPv6,
respectively. DHCPv6 does not provide the privacy protection on
messages and options. Other nodes can see the options transmitted in
DHCPv6 messages between DHCPv6 clients and servers. Extended
messages can be designed to secure the exchanges between DHCPv6
entities.
4.2.2. Options 4.2.2. Options
DHCPv6 allows defining options for common requirements, e.g., DNS and DHCPv6 allows defining options to transmit parameters between DHCP
NTP. In other cases, network operators may require DHCP messages to entities for common requirements, e.g., DNS [RFC3646] and SNTP
[RFC4075]. Also, these parameters may come from external entities.
For example, [RFC7037] defines RADIUS option to exchange
authorization and identification information between the DHCPv6 relay
agent and DHCPv6 server.
In other cases, network operators may require DHCP messages to
transmit some self-defined options between clients and servers. transmit some self-defined options between clients and servers.
Currently, vendor-specific information option allows clients and Currently, vendor-specific information option allows clients and
servers to exchange vendor-specific information. Therefore, servers to exchange vendor-specific information. Therefore,
administrative domains can define and use sub-options of vendor- administrative domains can define and use sub-options of vendor-
specific option to serve their private purposes. The content of the specific option to serve their private purposes. The content of the
self-defined options may come from two sources: devices and users. self-defined options may come from two sources: devices and users.
If the content of self-defined options comes from users, two methods If the content of self-defined options comes from users, two methods
can be used to solve the problem. The first one is that the clients can be used to solve the problem. The first one is that the clients
provide related interfaces to receive such information, which is provide related interfaces to receive such information, which is
currently merely supported. The second one is that DHCPv6 relays currently merely supported. The second one is that DHCPv6 relays
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4.2.3. Message Processing Functions 4.2.3. Message Processing Functions
Although current commercial or open-source DHCP server software Although current commercial or open-source DHCP server software
provides comprehensive functionalities, they still cannot meet all provides comprehensive functionalities, they still cannot meet all
customers' requirements of processing DHCP requests. Therefore, they customers' requirements of processing DHCP requests. Therefore, they
will provide interfaces that customers can use to write their will provide interfaces that customers can use to write their
specific extensions to affect the way how DHCP servers handle and specific extensions to affect the way how DHCP servers handle and
respond to DHCP requests. For example, not all networks prefer to respond to DHCP requests. For example, not all networks prefer to
use DHCPv6 servers to assign the privacy-preserving random-form use DHCPv6 servers to assign the privacy-preserving random-form
addresses generated by some fixed address generation mechanism to addresses generated by some fixed address generation mechanism to
DHCPv6 clients. Several address generation mechanisms for SLAAC DHCPv6 clients. Thus, network operators may alter their DHCPv6
[RFC4862] (e.g., IEEE 64-bit EUI-64 [RFC2464], Constant, semantically servers through the given extensions to use their own preferred
opaque [Microsoft], Temporary [RFC4941], and Stable, semantically address generation mechanisms to assign addresses to DHCPv6 clients.
opaque [RFC7217]) proposed for different requirements can be utilized
in DHCPv6 protocol as well. The many types of IPv6 address
generation mechanisms available have brought about flexibility and
diversity. Thus, network operators may alter their DHCPv6 servers
through the given extensions to use their own preferred address
generation mechanisms to assign addresses to DHCPv6 clients.
However, not all DHCP software considers this extension. However, not all DHCP software considers this extension.
4.2.4. Address Generation Mechanisms 4.2.4. Address Generation Mechanisms
Currently, the DHCPv6 servers assign addresses, prefixes and other Currently, the DHCPv6 servers assign addresses, prefixes and other
configuration options according to their configured policies. configuration options according to their configured policies.
Generally, different networks may prefer different address generation Generally, different networks may prefer different address generation
mechanisms. Corresponding interfaces could be open and defined to mechanisms. Several address generation mechanisms for SLAAC
allow other address generation mechanisms to be configured. [RFC4862] (e.g., IEEE 64-bit EUI-64 [RFC2464], Constant, semantically
opaque [Microsoft], Temporary [RFC4941], and Stable, semantically
4.2.5. Extension Principles opaque [RFC7217]) proposed for different requirements can be utilized
in DHCPv6 protocol as well. The many types of IPv6 address
The principles used to conduct multi-requirement extensions for generation mechanisms available have brought about flexibility and
DHCPv6 are summarized as follows: diversity. Therefore, corresponding interfaces could be open and
defined to allow other address generation mechanisms to be
1) Do not change the current DHCP general model. configured.
2) Use simpler interfaces to define and support more extensions.
5. Extension Cases 5. Extension Cases
Administrative domains may enforce local policies according to their Administrative domains may enforce local policies according to their
requirements, e.g., authentication, accountability. Several kinds of requirements, e.g., authentication, accountability. Several kinds of
multi-requirement extensions are presented in this section, including multi-requirement extensions are presented in this section, including
configurations in current DHCP software, option definition and server configurations in current DHCP software, option definition and server
modification, and message definition between DHCP entities and third- modification, and message definition between DHCP entities and third-
party entities. party entities.
skipping to change at page 8, line 37 skipping to change at page 8, line 42
[draft-ren-dhc-mredhcpv6] are contained in this document. [draft-ren-dhc-mredhcpv6] are contained in this document.
9. Normative References 9. Normative References
[CPNR] Cisco, "Cisco Prime Network Registrar", 2018, [CPNR] Cisco, "Cisco Prime Network Registrar", 2018,
<https://www.cisco.com/c/en/us/products/cloud-systems- <https://www.cisco.com/c/en/us/products/cloud-systems-
management/prime-network-registrar/index.html>. management/prime-network-registrar/index.html>.
[DHCP_Broadband] [DHCP_Broadband]
Weird Solutions, "DHCP Broadband", 2018, Weird Solutions, "DHCP Broadband", 2018,
<https://www.weird-solutions.com/carrier-solutions/ <https://www.weird-solutions.com/carrier-solutions/dhcp-
dhcp-broadband>. broadband>.
[draft-ren-dhc-mredhcpv6] [draft-ren-dhc-mredhcpv6]
Ren, G., He, L., and Y. Liu, "Multi-requirement Extensions Ren, G., He, L., and Y. Liu, "Multi-requirement Extensions
for Dynamic Host Configuration Protocol for IPv6 for Dynamic Host Configuration Protocol for IPv6
(DHCPv6)", March 2017. (DHCPv6)", March 2017.
[FreeRADIUS_DHCP] [FreeRADIUS_DHCP]
FreeRADIUS, "FreeRADIUS DHCP", 2017, FreeRADIUS, "FreeRADIUS DHCP", 2017,
<https://wiki.freeradius.org/features/DHCP>. <https://wiki.freeradius.org/features/DHCP>.
skipping to change at page 9, line 38 skipping to change at page 9, line 46
[Nominum_DHCP] [Nominum_DHCP]
Nominum, "Nominum DHCP", 2012, Nominum, "Nominum DHCP", 2012,
<https://www.nominum.com/press_item/nominum-releases-new- <https://www.nominum.com/press_item/nominum-releases-new-
version-of-carrier-grade-dhcp-software-for-telecom- version-of-carrier-grade-dhcp-software-for-telecom-
providers/>. providers/>.
[RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet
Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998,
<https://www.rfc-editor.org/info/rfc2464>. <https://www.rfc-editor.org/info/rfc2464>.
[RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic
Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
DOI 10.17487/RFC3646, December 2003,
<https://www.rfc-editor.org/info/rfc3646>.
[RFC4075] Kalusivalingam, V., "Simple Network Time Protocol (SNTP)
Configuration Option for DHCPv6", RFC 4075,
DOI 10.17487/RFC4075, May 2005,
<https://www.rfc-editor.org/info/rfc4075>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>. <https://www.rfc-editor.org/info/rfc4862>.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007,
<https://www.rfc-editor.org/info/rfc4941>. <https://www.rfc-editor.org/info/rfc4941>.
[RFC5007] Brzozowski, J., Kinnear, K., Volz, B., and S. Zeng,
"DHCPv6 Leasequery", RFC 5007, DOI 10.17487/RFC5007,
September 2007, <https://www.rfc-editor.org/info/rfc5007>.
[RFC7037] Yeh, L. and M. Boucadair, "RADIUS Option for the DHCPv6 [RFC7037] Yeh, L. and M. Boucadair, "RADIUS Option for the DHCPv6
Relay Agent", RFC 7037, DOI 10.17487/RFC7037, October Relay Agent", RFC 7037, DOI 10.17487/RFC7037, October
2013, <https://www.rfc-editor.org/info/rfc7037>. 2013, <https://www.rfc-editor.org/info/rfc7037>.
[RFC7217] Gont, F., "A Method for Generating Semantically Opaque [RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217, Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014, DOI 10.17487/RFC7217, April 2014,
<https://www.rfc-editor.org/info/rfc7217>. <https://www.rfc-editor.org/info/rfc7217>.
skipping to change at page 10, line 32 skipping to change at page 11, line 7
<https://www.rfc-editor.org/info/rfc7824>. <https://www.rfc-editor.org/info/rfc7824>.
[RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A., [RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A.,
Richardson, M., Jiang, S., Lemon, T., and T. Winters, Richardson, M., Jiang, S., Lemon, T., and T. Winters,
"Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 8415, DOI 10.17487/RFC8415, November 2018, RFC 8415, DOI 10.17487/RFC8415, November 2018,
<https://www.rfc-editor.org/info/rfc8415>. <https://www.rfc-editor.org/info/rfc8415>.
[VitalQIP] [VitalQIP]
Nokia, "Nokia VitalQIP", 2017, Nokia, "Nokia VitalQIP", 2017,
<https://networks.nokia.com/products/ <https://networks.nokia.com/products/vitalqip-ip-address-
vitalqip-ip-address-management>. management>.
[WIDE_DHCPv6] [WIDE_DHCPv6]
KAME project, "WIDE DHCPv6", 2008, KAME project, "WIDE DHCPv6", 2008,
<http://ipv6int.net/software/wide_dhcpv6.html>. <http://ipv6int.net/software/wide_dhcpv6.html>.
Authors' Addresses Authors' Addresses
Gang Ren Gang Ren
Tsinghua University Tsinghua University
Beijing 100084 Beijing 100084
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