RADIUS Option for DHCPv6 Relay Agents on Broadband Access Server
draft-ietf-dhc-dhcpv6-radius-opt-02
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7037.
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|
|---|---|---|---|
| Authors | Leaf Yeh , Mohamed Boucadair , Ted Lemon | ||
| Last updated | 2012-10-14 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-dhc-dhcpv6-radius-opt-02
DHC Working Group L. Yeh
Internet-Draft Huawei Technologies
Intended status: Standards Track M. Boucadair
Expires: April 15, 2013 France Telecom
T. Lemon
Nominum, Inc
October 12, 2012
RADIUS Option for DHCPv6 Relay Agents on Broadband Access Server
draft-ietf-dhc-dhcpv6-radius-opt-02
Abstract
The DHCPv6 RADIUS option provides a mechanism to exchange
authorization and identification information between relay agent and
server. This mechanism is meant to the centralized DHCPv6 server to
select the right configuration for the requesting client based on the
authorization information received from the RADIUS server, which is
not co-located with the DHCPv6 server. NAS acts as DHCPv6 relay
agent and RADIUS client simultaneously in this document.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on April 15, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Language . . . . . . . . . . . . . . . . . . . 3
3. Network Scenarios . . . . . . . . . . . . . . . . . . . . . . . 4
4. OPTION_RADIUS . . . . . . . . . . . . . . . . . . . . . . . . . 6
5. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . . 6
6. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Client Behavior . . . . . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
11.1. Normative References . . . . . . . . . . . . . . . . . . . 7
11.2. Informative References . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
DHCPv6 provides a mechanism that allows the server to assign or
delegate both stateful and stateless configuration parameters to the
clients. The stateful configuration parameters include IPv6 address
[RFC3315], IPv6 prefix [RFC3633], etc. The stateless configuration
parameters [RFC3736] include, for example, DNS [RFC3646], or a FQDN
of AFTR [RFC6334]. In this document, the DHCPv6 server is deployed
in the central part of an ISP network.
RADIUS [RFC2865] is widely used as the centralized authentication,
authorization and user management mechanism for the service provision
in Broadband access network. [RFC3162], [RFC4818], [RFC6519] and
[I-D.ietf-radext-ipv6-access] specified attributes that support the
service provision for IPv6-only and IPv6-transition access. RADIUS
server authorizes the NAS to assign an IPv6 address or prefix from
the indicated pool, or to assign an IPv6 address or prefix with an
explicitly indicated value, and other configuration parameters as per
the attributes for the subscribers.
These mechanisms work well in the deployment scenarios where the NAS
acts as the distributed DHCPv6 server. In that case the NAS directly
responds the DHCPv6 messages as per the indication conveyed by the
attributes in the Access-Accept message from the RADIUS server.
These mechanisms might also work well in the scenario where the
centralized DHCPv6 server is co-located with the RADIUS server, where
they can share the same database of the users. But when the NAS acts
as the relay agent and RADIUS client simultaneously, and the
centralized DHCPv6 server is not located in the same place as the
RADIUS server, a new communication mechanism is needed for the relay
agent to transfer the authorization information indicated by the
RADIUS attributes to the DHCPv6 server.
2. Terminology and Language
This document specifies a DHCPv6 option for the distributed Relay
Agent to transfer the authorization information of RADIUS attributes
received in the Access-Accept message to the centralized DHCPv6
server. Definitions for terms and acronyms not specified in this
document are defined in [RFC2865] and [RFC3315].
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 BCP 14, [RFC2119].
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3. Network Scenarios
Figure 1 and Figure 2 shows the typical network scenarios where the
communication mechanism introduced in this document is necessary. In
these scenarios, the centralized DHCPv6 server is not co-located with
the RADIUS server, but both of them are in the same administrative
domain. The NAS acts as the relay agent and the RADIUS client
simultaneously. Figure 1 shows the sequence of DHCPv6 and RADIUS
messages for IPoE access mode. Figure 2 shows the sequence of DHCPv6
and RADIUS messages for PPPoE access mode.
+-------+ +-------+ +-------+
|DHCPv6 | Access Mode: | NAS | |Radius |
|Client | IPoE | | |Server |
+-------+ +-------+ +-------+
| | |
|---Solicit---------------->| |
| |---Access-Request---------->|
| | |
| |<--Access-Accept------------|
| |(e.g. Delegated-IPv6-Prefix)|
| | |
DHCPv6 messages RADIUS messages
+-------+
|DHCPv6 |
|Server |
+-------+
| | |
| |---Relay-Forward----------->|
| | (OPTION_RADIUS) |
| | |
| |<--Relay-Reply -------------|
|<--Advertise---------------| |
| (e.g. IA_PD) | |
| | |
|---Request---------------->| |
| (e.g. IA_PD) |---Relay-Forward----------->|
| | (OPTION_RADIUS) |
| | |
| |<--Relay-Reply -------------|
|<--Reply-------------------| |
| (e.g. IA_PD) | |
| | |
DHCPv6 messages DHCPv6 messages
Figure 1: Network scenario and message sequence when employing DHCPv6
RADIUS option in IPoE access
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+-------+ +-------+ +-------+
|DHCPv6 | Access Mode: | NAS | |Radius |
|Client | PPPoE | | |Server |
+-------+ +-------+ +-------+
| | |
|--PPP LCP Config-Request-->| |
| |---Access-Request---------->|
| | |
| |<--Access-Accept------------|
|<----PPP LCP Config-ACK----|(e.g. Delegated-IPv6-Prefix)|
| | |
PPP messages RADIUS messages
+-------+
|DHCPv6 |
|Server |
+-------+
| | |
|---Solicit---------------->| |
| |---Relay-Forward----------->|
| | (OPTION_RADIUS) |
| | |
| |<--Relay-Reply -------------|
|<--Advertise---------------| |
| (e.g. IA_PD) | |
| | |
|---Request---------------->| |
| (e.g. IA_PD) |---Relay-Forward----------->|
| | (OPTION_RADIUS)
| | |
| |<--Relay-Reply -------------|
|<--Reply-------------------| |
| (e.g. IA_PD) | |
| | |
DHCPv6 messages DHCPv6 messages
Figure 2: Network scenario and message sequence when employing DHCPv6
RADIUS option in PPPoE access
If the authorization through RADIUS fails, the associated message
sequences will stop. The DHCPv6 relay will not forward the message
from the client to the server. After receiving RENEW (5) message
from the DHCPv6 client, NAS does not have to initiate a new Access-
Request/Access message exchange with the RADIUS server; but after
receiving REBIND (6) message from the DHCPv6 client, NAS has to
initiate a new Access-Request/Access message exchange with the RADIUS
server.
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4. OPTION_RADIUS
The OPTION_RADIUS is a stateless DHCPv6 option, and is used by the
relay agent to carry the authorization information of RADIUS
attributes received in the Access-Accept message.
The format of the OPTION_RADIUS option is defined as follows:
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_RADIUS | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-data (List of RADIUS Attributes)
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code TBD
option-length Length of the option-data in Octets
option-data One or a list of RADIUS Attributes
The option-data of OPTION_RADIUS is one or a list of RADIUS
attributes received in the Access-Accept message from the RADIUS
server. As the same method in [RFC4014], only the attributes listed
in the table below may be included in the OPTION_RADIUS.
Type Code Attribute Reference
26 Vendor-Specific [RFC2865]
123 Delegated-IPv6-Prefix [RFC4818]
144 DS-Lite-Tunnel-Name [RFC6519]
[TBD] Framed-IPv6-Address [I-D.ietf-radext-ipv6-access]
[TBD] Stateful-IPv6-Address-Pool [I-D.ietf-radext-ipv6-access]
[TBD] Delegated-IPv6-Prefix-Pool [I-D.ietf-radext-ipv6-access]
[TBD] DNS-Server-IPv6-Address [I-D.ietf-radext-ipv6-access]
Note: The above table might have more attributes to join in the
future.
5. Relay Agent Behavior
The DHCPv6 relay agent may include OPTION_RADIUS in the RELAY-FORW
(12) message. When the value in the attributes of Stateful-IPv6-
Address-Pool, Delegated-IPv6-Prefix-Pool, Delegated-IPv6-Prefix (123)
or Framed-IPv6-Address in the Access-Accept message replied from
RADIUS server are valid, the relay agent that supports OPTION_RADIUS
SHOULD include these RADIUS attributes into the container option,
OPTION_RADIUS. The relay agent MUST silently discard OPTION_RADIUS
if received.
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6. Server Behavior
Upon receipt of the RELAY-FORW (12) message with OPTION_RADIUS from a
relay agent, the DHCPv6 server SHOULD extract and interpret the
RADIUS attributes in the OPTION_RADIUS, and use that information in
selecting configuration parameters for the requesting client. If the
DHCPv6 server does not support OPTION_RADIUS, the DHCPv6 server MUST
silently discard this option. The DHCPv6 server MUST NOT include
OPTION_RADIUS in RELAY-REPL (13) messages.
7. Client Behavior
OPTION_RADIUS option is only sent from the relay agents to the
servers. DHCPv6 clients are not aware of the usage of OPTION_RADIUS.
DHCPv6 Client MUST NOT send OPTION_RADIUS, and MUST ignore
OPTION_RADIUS if received.
8. Security Considerations
Known security vulnerabilities of the DHCPv6 and RADIUS protocol may
apply to its options. Security issues related with DHCPv6 are
described in section 23 of [RFC3315]. Security issues related with
RADIUS are described in section 8 of [RFC2865], section 5 of
[RFC3162].
9. IANA Considerations
The authors of this document request to assign a new DHCPv6 option
code for OPTION_RADIUS.
10. Acknowledgements
Expert comments from Bernie Volz and Tomek Mrugalski for the
discussion on the technology selection in the mailing list are
appreciated.
11. References
11.1. Normative References
[I-D.ietf-radext-ipv6-access]
Dec, W., Sarikaya, B., Zorn, G., Miles, D., and B.
Lourdelet, "RADIUS attributes for IPv6 Access Networks",
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draft-ietf-radext-ipv6-access-11 (work in progress),
August 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol
(DHCP) Service for IPv6", RFC 3736, April 2004.
[RFC4014] Droms, R. and J. Schnizlein, "Remote Authentication
Dial-In User Service (RADIUS) Attributes Suboption for the
Dynamic Host Configuration Protocol (DHCP) Relay Agent
Information Option", RFC 4014, February 2005.
[RFC4818] Salowey, J. and R. Droms, "RADIUS Delegated-IPv6-Prefix
Attribute", RFC 4818, April 2007.
[RFC6519] Maglione, R. and A. Durand, "RADIUS Extensions for Dual-
Stack Lite", RFC 6519, February 2012.
11.2. Informative References
[RFC3162] Aboba, B., Zorn, G., and D. Mitton, "RADIUS and IPv6",
RFC 3162, August 2001.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC3646] Droms, R., "DNS Configuration options for Dynamic Host
Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
December 2003.
[RFC6334] Hankins, D. and T. Mrugalski, "Dynamic Host Configuration
Protocol for IPv6 (DHCPv6) Option for Dual-Stack Lite",
RFC 6334, August 2011.
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Authors' Addresses
Leaf Y. Yeh
Huawei Technologies
P. R. China
Email: leaf.y.yeh@huawei.com
Mohamed Boucadair
France Telecom
France
Email: mohamed.boucadair@orange.com
Ted Lemon
Nominum, Inc
USA
Email: Ted.Lemon@nominum.com
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