Network Working Group                                      Bernard Aboba
INTERNET-DRAFT                                                 Microsoft
Category: Standards Track                                      Glen Zorn
<draft-aboba-radius-ipv6-01.txt>                           Cisco Systems
26 August 2000                                               Dave Mitton
                                                         Nortel Networks


                            RADIUS and IPv6

This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.

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://www.ietf.org/ietf/1id-abstracts.txt

The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

11..  Copyright Notice

Copyright (C) The Internet Society (2000).  All Rights Reserved.

22..  Abstract

This document specifies the operation of RADIUS when run over IPv6 as
well as the RADIUS attributes used to support IPv6 network access. A
companion document, draft-itojun-ipv6-dialup-radius-0x.txt, describes
scenarios in which these attributes may be used.

33..  Introduction

This document specifies the operation of RADIUS when run over IPv6 as
well as the RADIUS attributes used to support IPv6 network access. A
companion document, draft-itojun-ipv6-dialup-radius-0x.txt [11],
describes scenarios in which these attributes may be used.

Note that the RADIUS server does not know a priori whether the NAS will
be using IPv4, IPv6, or both. Therefore it is presumed that the IPv6



Aboba, Zorn & Mitton         Standards Track                    [Page 1]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


attributes described in this document may be sent along with
IPv4-related attributes within the same RADIUS message and that the NAS
will decide which attributes to use.

The NAS can provide IPv6 access natively, or alternatively, via a tunnel
(6BONE). The choice of method for providing IPv6 access has no effect on
RADIUS usage per se, although if it is desired that an IPv6 within IPv4
tunnel be opened to a particular location, then tunnel attributes should
be utilized, as described in [7]-[8].

33..11..  Requirements language

In this document, the key words "MAY", "MUST,  "MUST  NOT",  "optional",
"recommended",  "SHOULD",  and  "SHOULD  NOT",  are to be interpreted as
described in [1].

44..  Attributes

44..11..  NAS-IPv6-Address

Description

   This Attribute indicates the identifying IPv6 Address of the NAS
   which is requesting authentication of the user, and SHOULD be unique
   to the NAS within the scope of the RADIUS server.  NAS-IPv6-Address
   is only used in Access-Request packets.  NAS-IPv6-Address and/or NAS-
   IP-Address MAY be present in an Access-Request packet; however, if
   neither attribute is present then NAS-Identifier MUST be present.

A summary of the NAS-IPv6-Address Attribute format is shown below.  The
fields are transmitted from left to right.

 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     Type      |    Length     |             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            Address             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Type




Aboba, Zorn & Mitton         Standards Track                    [Page 2]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


   TBD for NAS-IPv6-Address

Length

   18

Address

   The Address field is 16 octets.

44..22..  Framed-Interface-Id

Description

   This Attribute indicates the IPv6 interface identifier to be
   configured for the user. It MAY be used in Access-Accept packets. It
   MAY be used in an Access-Request packet as a hint by the NAS to the
   server that it would prefer that address, but the server is not
   required to honor the hint.

A summary of the Framed-Interface-Id Attribute format is shown below.
The fields are transmitted from left to right.

 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     Type      |    Length     |             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         Address                |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Type

   TBD for Framed-Interface-Id

Length

   10

Address

   The Address field is 8 octets.







Aboba, Zorn & Mitton         Standards Track                    [Page 3]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


44..33..  Framed-IPv6-Prefix

Description

   This Attribute indicates the IPv6 prefix to be configured for the
   user. It MAY be used in Access-Accept packets.  It MAY be used in an
   Access-Request packet as a hint by the NAS to the server that it
   would prefer that address, but the server is not required to honor
   the hint.

A summary of the Framed-IPv6-Prefix Attribute format is shown below.
The fields are transmitted from left to right.

 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     Type      |    Length     |    Reserved   |   Prefix      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address                            |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Type

   TBD for Framed-IPv6-Prefix

Length

   At least 2 and no larger than 20.

Reserved

   This field is reserved and MUST be set to zero.

Prefix

   The length of the prefix, in bits. At least 0 and no larger than 128.

Address

   The Address field is up to 16 octets in length. Bits outside of the
   prefix length, if included, must be zero.




Aboba, Zorn & Mitton         Standards Track                    [Page 4]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


44..44..  Login-IPv6-Host

Description

   This Attribute indicates the system with which to connect the user,
   when the Login-Service Attribute is included. It MAY be used in
   Access-Accept packets. It MAY be used in an Access-Request packet as
   a hint to the server that the NAS would prefer to use that host, but
   the server is not required to honor the hint.

A summary of the Login-IPv6-Host Attribute format is shown below.  The
fields are transmitted from left to right.

 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     Type      |    Length     |             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                             Address
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         Address                |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Type

   TBD for Login-IPv6-Host

Length

   18.

Address

   The Address field is 16 octets in length. The value
   0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF indicates that the NAS SHOULD
   allow the user to select an address.  The value 0 indicates that the
   NAS SHOULD select a host to connect the user to. Other values
   indicate the address the NAS SHOULD connect the user to.

44..55..  Framed-IPv6-Route

Description

   This Attribute provides routing information to be configured for the



Aboba, Zorn & Mitton         Standards Track                    [Page 5]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


   user on the NAS.  It is used in the Access-Accept packet and can
   appear multiple times.

A summary of the Framed-IPv6-Route Attribute format is shown below.  The
fields are transmitted from left to right.

 0                   1                   2
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
|     Type      |    Length     |  Text ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-

Type

   TBD for Framed-IPv6-Route

Length

   >=3

Text

   The Text field is one or more octets, and its contents are
   implementation dependent.  It is intended to be human readable and
   MUST NOT affect operation of the protocol.  It is recommended that
   the message contain UTF-8 encoded 10646 [2] characters.

   For IPv6 routes, it SHOULD contain a destination prefix optionally
   followed by a slash and a decimal length specifier stating how many
   high order bits of the prefix to use. That is followed by a space, a
   gateway address, a space, and one or more metrics separated by
   spaces.

   Whenever the gateway address is specified as zero the IP address of
   the user SHOULD be used as the gateway address.

55..  Table of Attributes

The following table provides a guide to which attributes may be found in
which kinds of packets, and in what quantity.

   Request   Accept   Reject   Challenge   #    Attribute
   0-1       0        0        0          TBD   NAS-IPv6-Address
   0-1       0-1      0        0          TBD   Framed-Interface-Id
   0-1       0-1      0        0          TBD   Framed-IPv6-Prefix
   0+        0+       0        0          TBD   Login-IPv6-Host
   0         0+       0        0          TBD   Framed-IPv6-Route
   Request   Accept   Reject   Challenge   #    Attribute



Aboba, Zorn & Mitton         Standards Track                    [Page 6]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


66..  References


[1]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
     Levels", RFC 2119, March, 1997.

[2]  Yergeau, F., "UTF-8, a transformation format of Unicode and ISO
     10646", RFC 2044, October 1996.

[3]  Aboba, B., and Vollbrecht, J., "Proxy Chaining and Policy
     Implementation in Roaming", RFC 2607, June 1999.

[4]  Rigney, C., Rubens, A., Simpson, W., Willens, S.,  "Remote
     Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000.

[5]  Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.

[6]  Rigney, C., Willats, W., Calhoun, P., "RADIUS Extensions", RFC
     2869, June 2000.

[7]  Zorn, G., Leifer, D., Rubens, A., Shriver, J., Holdrege, M.,
     Goyret, I., "RADIUS Attributes for Tunnel Protocol Support", RFC
     2868, June 2000.

[8]  Zorn, G., Mitton, D., Aboba, B., "RADIUS Accounting Modifications
     for Tunnel Protocol Support", RFC 2867, June 2000.

[9]  Kent S., Atkinson, R., "Security Architecture for the Internet
     Protocol", RFC 2401, November 1998.

[10] Alvestrand, H. and T. Narten, "Guidelines for Writing an IANA
     Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.

[11] Hagino, J., Yamamoto, K., "A RADIUS attribute for IPv6 dialup PPP
     with static address assignment", draft-itojun-ipv6-dialup-
     radius-00.txt, July 2000.

77..  Security Considerations

This draft describes the use of RADIUS for the purposes of
authentication, authorization and accounting in IPv6-enabled networks.
In such networks, the RADIUS protocol may run either over IPv4 or over
IPv6. Known security vulnerabilities of the RADIUS protocol are
described in [6] and [3].

Since IPSEC [9] is mandatory to implement for IPv6, it is expected that
running RADIUS implementations supporting IPv6 will typically run over
IPSEC. Where RADIUS is run over IPSEC and where certificates are used



Aboba, Zorn & Mitton         Standards Track                    [Page 7]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


for authentication, it may be desirable to avoid management of RADIUS
shared secrets, so as to leverage the improved scalability of public key
infrastructure.

Within RADIUS, a shared secret is used for hiding of attributes such as
User-Password [4] and Tunnel-Password [7]. In addition, the shared
secret is used in computation of the Response Authenticator [4], as well
as the Message-Authenticator attribute [6]. Therefore, in RADIUS a
shared secret is used to provide confidentiality as well as integrity
protection and authentication. As a result, only use of IPSEC ESP with a
non-null transform can provide security services sufficient to
substitute for RADIUS application-layer security. Therefore, where IPSEC
AH or ESP null is used, it will typically still be necessary to
configure a RADIUS shared secret.

However, where RADIUS is run over IPSEC ESP with a non-null transform,
the secret shared between the NAS and the RADIUS server MAY NOT be
configured. In this case, a shared secret of zero length MUST be
assumed.

88..  IANA Considerations

This draft requires the assignment of five new RADIUS attribute numbers
for the following attributes:

NAS-IPv6-Address
Framed-Interface-Id
Framed-IPv6-Prefix
Login-IPv6-Host
Framed-IPv6-Route

99..  Acknowledgments

The authors would like to acknowledge Jun-ichiro itojun Hagino of IIJ
Research Laboratory, Darran Potter of Cisco and Carl Rigney of Lucent
for contributions to this document.

1100..  Authors' Addresses

Bernard Aboba
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052

EMail: bernarda@microsoft.com
Phone: +1 425 936 6605
Fax:   +1 425 936 7329




Aboba, Zorn & Mitton         Standards Track                    [Page 8]


INTERNET-DRAFT              RADIUS and IPv6               26 August 2000


Glen Zorn
Cisco Systems, Inc.
500 108th Avenue N.E., Suite 500
Bellevue, WA 98004

Phone: +1 425 468 0955
Email: gwz@cisco.com

Dave Mitton
Nortel Networks
880 Technology Park Drive
Billerica, MA 01821

Phone: +1 978 288 4570
Fax:   +1 978 288 3030
EMail: dmitton@nortelnetworks.com

1111..  Full Copyright Statement

Copyright (C) The Internet Society (2000).  All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it or
assist in its implementation may be prepared, copied, published and
distributed, in whole or in part, without restriction of any kind,
provided that the above copyright notice and this paragraph are included
on all such copies and derivative works.  However, this document itself
may not be modified in any way, such as by removing the copyright notice
or references to the Internet Society or other Internet organizations,
except as needed for the purpose of developing Internet standards in
which case the procedures for copyrights defined in the Internet
Standards process must be followed, or as required to translate it into
languages other than English.  The limited permissions granted above are
perpetual and will not be revoked by the Internet Society or its
successors or assigns.  This document and the information contained
herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE
INTERNET ENGINEERING TASK FORCE DISCLAIMS 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."

1122..  Expiration Date

This memo is filed as <draft-aboba-radius-ipv6-01.txt>,  and  expires
May 1, 2001.







Aboba, Zorn & Mitton         Standards Track                    [Page 9]