draft-ietf-radext-rfc2486bis-01.txt   draft-ietf-radext-rfc2486bis-02.txt 
Network Working Group B. Aboba Network Working Group B. Aboba
Internet-Draft Microsoft Internet-Draft Microsoft
Expires: April 19, 2005 M. Beadles Expires: May 5, 2005 M. Beadles
SmartPipes SmartPipes
J. Arkko J. Arkko
Ericsson Ericsson
P. Eronen P. Eronen
Nokia Nokia
October 19, 2004 November 4, 2004
The Network Access Identifier The Network Access Identifier
draft-ietf-radext-rfc2486bis-01 draft-ietf-radext-rfc2486bis-02
Status of this Memo Status of this Memo
This document is an Internet-Draft and is subject to all provisions This document is an Internet-Draft and is subject to all provisions
of section 3 of RFC 3667. By submitting this Internet-Draft, each of section 3 of RFC 3667. By submitting this Internet-Draft, each
author represents that any applicable patent or other IPR claims of author represents that any 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 is aware have been or will be disclosed, and any of
which he or she become aware will be disclosed, in accordance with which he or she become aware will be disclosed, in accordance with
RFC 3668. RFC 3668.
skipping to change at page 1, line 41 skipping to change at page 1, line 40
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
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on April 19, 2005. This Internet-Draft will expire on May 5, 2005.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2004). Copyright (C) The Internet Society (2004).
Abstract Abstract
In order to provide roaming services, it is necessary to have a In order to provide roaming services, it is necessary to have a
standardized method for identifying users. This document defines the standardized method for identifying users. This document defines the
syntax for the Network Access Identifier (NAI), the user identity syntax for the Network Access Identifier (NAI), the user identity
skipping to change at page 2, line 18 skipping to change at page 2, line 18
relationship with only one. Examples of where roaming capabilities relationship with only one. Examples of where roaming capabilities
might be required include ISP "confederations" and ISP-provided might be required include ISP "confederations" and ISP-provided
corporate network access support. This document is a revised version corporate network access support. This document is a revised version
of RFC 2486 which originally defined NAIs. Enhancements include of RFC 2486 which originally defined NAIs. Enhancements include
international character set and privacy support, as well as a number international character set and privacy support, as well as a number
of corrections to the original RFC. of corrections to the original RFC.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Terminology . . . . . . . . . . . . . . . . . . . . . 3 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Requirements language . . . . . . . . . . . . . . . . 4 1.2 Requirements language . . . . . . . . . . . . . . . . . . 4
1.3 Purpose . . . . . . . . . . . . . . . . . . . . . . . 4 1.3 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. NAI Definition . . . . . . . . . . . . . . . . . . . . . . . . 5 2. NAI Definition . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Formal Syntax . . . . . . . . . . . . . . . . . . . . 5 2.1 Formal Syntax . . . . . . . . . . . . . . . . . . . . . . 5
2.2 NAI Length Considerations . . . . . . . . . . . . . . 6 2.2 NAI Length Considerations . . . . . . . . . . . . . . . . 6
2.3 Support for Username Privacy . . . . . . . . . . . . . 6 2.3 Support for Username Privacy . . . . . . . . . . . . . . . 7
2.4 International Character Sets . . . . . . . . . . . . . 7 2.4 International Character Sets . . . . . . . . . . . . . . . 7
2.5 Compatibility with E-Mail Usernames . . . . . . . . . 7 2.5 Compatibility with E-Mail Usernames . . . . . . . . . . . 7
2.6 Compatibility with DNS . . . . . . . . . . . . . . . . 7 2.6 Compatibility with DNS . . . . . . . . . . . . . . . . . . 8
2.7 Realm Construction . . . . . . . . . . . . . . . . . . 8 2.7 Realm Construction . . . . . . . . . . . . . . . . . . . . 8
2.8 Examples . . . . . . . . . . . . . . . . . . . . . . . 9 2.8 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 9
3. Security Considerations . . . . . . . . . . . . . . . . . . . 10 3. Security Considerations . . . . . . . . . . . . . . . . . . . 10
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1 Normative References . . . . . . . . . . . . . . . . . . 12 5.1 Normative References . . . . . . . . . . . . . . . . . . . . 11
5.2 Informative References . . . . . . . . . . . . . . . . . 12 5.2 Informative References . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 12
A. Changes from RFC 2486 . . . . . . . . . . . . . . . . . . . . 14 A. Changes from RFC 2486 . . . . . . . . . . . . . . . . . . . . 12
B. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15 B. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
Intellectual Property and Copyright Statements . . . . . . . . 16 Intellectual Property and Copyright Statements . . . . . . . . 15
1. Introduction 1. Introduction
Considerable interest exists for a set of features that fit within Considerable interest exists for a set of features that fit within
the general category of "roaming capability" for network access, the general category of "roaming capability" for network access,
including dialup Internet users, VPN usage, wireless LAN including dialup Internet users, VPN usage, wireless LAN
authentication, and other applications. Interested parties have authentication, and other applications. Interested parties have
included: included:
o Regional Internet Service Providers (ISPs) operating within a o Regional Internet Service Providers (ISPs) operating within a
particular state or province, looking to combine their efforts particular state or province, looking to combine their efforts
with those of other regional providers to offer dialup service with those of other regional providers to offer dialup service
over a wider area. over a wider area.
o National ISPs wishing to combine their operations with those of o National ISPs wishing to combine their operations with those of
one or more ISPs in another nation to offer more comprehensive one or more ISPs in another nation to offer more comprehensive
dialup service in a group of countries or on a continent. dialup service in a group of countries or on a continent.
o Wireless LAN hotspots providing service to one or more ISPs. o Wireless LAN hotspots providing service to one or more ISPs.
o Businesses desiring to offer their employees a comprehensive o Businesses desiring to offer their employees a comprehensive
package of dialup services on a global basis. Those services may package of dialup services on a global basis. Those services may
include Internet access as well as secure access to corporate include Internet access as well as secure access to corporate
intranets via a Virtual Private Network (VPN), enabled by intranets via a Virtual Private Network (VPN), enabled by
tunneling protocols such as PPTP, L2F, L2TP, and IPsec tunnel tunneling protocols such as PPTP, L2F, L2TP, and IPsec tunnel
mode. mode.
In order to enhance the interoperability of roaming services, it is In order to enhance the interoperability of roaming services, it is
necessary to have a standardized method for identifying users. This necessary to have a standardized method for identifying users. This
document defines syntax for the Network Access Identifier (NAI). document defines syntax for the Network Access Identifier (NAI).
skipping to change at page 3, line 31 skipping to change at page 3, line 35
package of dialup services on a global basis. Those services may package of dialup services on a global basis. Those services may
include Internet access as well as secure access to corporate include Internet access as well as secure access to corporate
intranets via a Virtual Private Network (VPN), enabled by intranets via a Virtual Private Network (VPN), enabled by
tunneling protocols such as PPTP, L2F, L2TP, and IPsec tunnel tunneling protocols such as PPTP, L2F, L2TP, and IPsec tunnel
mode. mode.
In order to enhance the interoperability of roaming services, it is In order to enhance the interoperability of roaming services, it is
necessary to have a standardized method for identifying users. This necessary to have a standardized method for identifying users. This
document defines syntax for the Network Access Identifier (NAI). document defines syntax for the Network Access Identifier (NAI).
Examples of implementations that use the NAI, and descriptions of its Examples of implementations that use the NAI, and descriptions of its
semantics, can be found in [7]. semantics, can be found in [RFC2194].
This document is a revised version of RFC 2486 which originally This document is a revised version of RFC 2486 [RFC2486] which
defined NAIs. Differences and enhancements compared to RFC 2486 are originally defined NAIs. Differences and enhancements compared to
listed in Appendix A. RFC 2486 are listed in Appendix A.
1.1 Terminology 1.1 Terminology
This document frequently uses the following terms: This document frequently uses the following terms:
Network Access Identifier Network Access Identifier
The Network Access Identifier (NAI) is the user identity submitted The Network Access Identifier (NAI) is the user identity submitted
by the client during network access authentication. In roaming, by the client during network access authentication. In roaming,
the purpose of the NAI is to identify the user as well as to the purpose of the NAI is to identify the user as well as to
assist in the routing of the authentication request. Please note assist in the routing of the authentication request. Please note
that the NAI may not necessarily be the same as the user's e-mail that the NAI may not necessarily be the same as the user's e-mail
address or the user identity submitted in an application layer address or the user identity submitted in an application layer
authentication. authentication.
Network Access Server Network Access Server
The Network Access Server (NAS) is the device that clients connect The Network Access Server (NAS) is the device that clients connect
to in order to get access to the network. In PPTP terminology to in order to get access to the network. In PPTP terminology
this is referred to as the PPTP Access Concentrator (PAC), and in this is referred to as the PPTP Access Concentrator (PAC), and in
L2TP terminology, it is referred to as the L2TP Access L2TP terminology, it is referred to as the L2TP Access
Concentrator (LAC). In IEEE 802.11, it is referred to as an Concentrator (LAC). In IEEE 802.11, it is referred to as an
Access Point. Access Point.
Roaming Capability Roaming Capability
Roaming capability can be loosely defined as the ability to use Roaming capability can be loosely defined as the ability to use
any one of multiple Internet service providers (ISPs), while any one of multiple Internet service providers (ISPs), while
maintaining a formal, customer-vendor relationship with only one. maintaining a formal, customer-vendor relationship with only one.
Examples of cases where roaming capability might be required Examples of cases where roaming capability might be required
include ISP "confederations" and ISP- provided corporate network include ISP "confederations" and ISP- provided corporate network
access support. access support.
Tunneling Service Tunneling Service
A tunneling service is any network service enabled by tunneling A tunneling service is any network service enabled by tunneling
protocols such as PPTP, L2F, L2TP, and IPsec tunnel mode. One protocols such as PPTP, L2F, L2TP, and IPsec tunnel mode. One
example of a tunneling service is secure access to corporate example of a tunneling service is secure access to corporate
intranets via a Virtual Private Network (VPN). intranets via a Virtual Private Network (VPN).
1.2 Requirements language 1.2 Requirements language
In this document, the key words "MAY", "MUST, "MUST NOT", "OPTIONAL", In this document, the key words "MAY", "MUST, "MUST NOT", "OPTIONAL",
skipping to change at page 4, line 27 skipping to change at page 4, line 40
A tunneling service is any network service enabled by tunneling A tunneling service is any network service enabled by tunneling
protocols such as PPTP, L2F, L2TP, and IPsec tunnel mode. One protocols such as PPTP, L2F, L2TP, and IPsec tunnel mode. One
example of a tunneling service is secure access to corporate example of a tunneling service is secure access to corporate
intranets via a Virtual Private Network (VPN). intranets via a Virtual Private Network (VPN).
1.2 Requirements language 1.2 Requirements language
In this document, the key words "MAY", "MUST, "MUST NOT", "OPTIONAL", In this document, the key words "MAY", "MUST, "MUST NOT", "OPTIONAL",
"RECOMMENDED", "SHOULD", and "SHOULD NOT", are to be interpreted as "RECOMMENDED", "SHOULD", and "SHOULD NOT", are to be interpreted as
described in [2]. described in [RFC2119].
1.3 Purpose 1.3 Purpose
As described in [7], there are a number of providers offering network As described in [RFC2194], there are a number of providers offering
access services, and the number of Internet Service Providers network access services, and the number of Internet Service Providers
involved in roaming consortia is increasing rapidly. involved in roaming consortia is increasing rapidly.
In order to be able to offer roaming capability, one of the In order to be able to offer roaming capability, one of the
requirements is to be able to identify the user's home authentication requirements is to be able to identify the user's home authentication
server. For use in roaming, this function is accomplished via the server. For use in roaming, this function is accomplished via the
Network Access Identifier (NAI) submitted by the user to the NAS in Network Access Identifier (NAI) submitted by the user to the NAS in
the initial network authentication. It is also expected that NASes the initial network authentication. It is also expected that NASes
will use the NAI as part of the process of opening a new tunnel, in will use the NAI as part of the process of opening a new tunnel, in
order to determine the tunnel endpoint. order to determine the tunnel endpoint.
2. NAI Definition 2. NAI Definition
2.1 Formal Syntax 2.1 Formal Syntax
The grammar for the NAI is given below, described in ABNF as The grammar for the NAI is given below, described in ABNF as
documented in [3]. The grammar for the username is based on [6], and documented in [RFC2234]. The grammar for the username is based on
the grammar for the realm is an updated version of [1]. [RFC0821], and the grammar for the realm is an updated version of
[RFC1035].
nai = username nai = username
nai =/ "@" realm nai =/ "@" realm
nai =/ username "@" realm nai =/ username "@" realm
username = dot-string username = dot-string
dot-string = string dot-string = string
dot-string =/ dot-string "." string dot-string =/ dot-string "." string
string = char string = char
string =/ string char string =/ string char
skipping to change at page 6, line 27 skipping to change at page 6, line 36
let-dig = alpha / digit let-dig = alpha / digit
alpha = %x41-5A ; 'A'-'Z' alpha = %x41-5A ; 'A'-'Z'
alpha =/ %x61-7A ; 'a'-'z' alpha =/ %x61-7A ; 'a'-'z'
digit = %x30-39 ; '0'-'9' digit = %x30-39 ; '0'-'9'
2.2 NAI Length Considerations 2.2 NAI Length Considerations
Devices handling NAIs MUST support an NAI length of at least 72 Devices handling NAIs MUST support an NAI length of at least 72
octets. Support for an NAI length of 253 octets is RECOMMENDED. octets. Support for an NAI length of 253 octets is RECOMMENDED.
However, the following implementation issues should be considered: However, the following implementation issues should be considered:
o NAIs are often transported in the User-Name attribute of RADIUS. o NAIs are often transported in the User-Name attribute of RADIUS.
Unfortunately, RFC 2865 [9] Section 5.1 states that "the ability Unfortunately, RFC 2865 [RFC2865] Section 5.1 states that "the
to handle at least 63 octets is recommended." As a result, it may ability to handle at least 63 octets is recommended." As a result,
not be possible to transfer NAIs beyond 63 octets through all it may not be possible to transfer NAIs beyond 63 octets through
devices. In addition, since only a single User-Name attribute may all devices. In addition, since only a single User-Name attribute
be included in a RADIUS message and the maximum attribute length may be included in a RADIUS message and the maximum attribute
is 253 octets, RADIUS is unable to support NAI lengths beyond 253 length is 253 octets, RADIUS is unable to support NAI lengths
octets. beyond 253 octets.
o NAIs can also be transported in the User-Name attribute of o NAIs can also be transported in the User-Name attribute of
Diameter [12], which supports content lengths up to 2^24 - 9 Diameter [RFC3588], which supports content lengths up to 2^24 - 9
octets. As a result, NAIs processed only by Diameter nodes can be octets. As a result, NAIs processed only by Diameter nodes can be
very long. Unfortunately, an NAI transported over Diameter may very long. Unfortunately, an NAI transported over Diameter may
eventually be translated to RADIUS, in which case the above eventually be translated to RADIUS, in which case the above
limitations apply. limitations apply.
2.3 Support for Username Privacy 2.3 Support for Username Privacy
Interpretation of the "username" part of the NAI depends on the realm Interpretation of the "username" part of the NAI depends on the realm
in question. Therefore, the "username" part SHOULD be treated as in question. Therefore, the "username" part SHOULD be treated as
opaque data when processed by nodes that are not a part of the opaque data when processed by nodes that are not a part of the
skipping to change at page 7, line 20 skipping to change at page 7, line 33
the authentication conversation can proceed. As a result, the realm the authentication conversation can proceed. As a result, the realm
portion is typically required in order for the authentication portion is typically required in order for the authentication
exchange to be routed to the appropriate server. exchange to be routed to the appropriate server.
2.4 International Character Sets 2.4 International Character Sets
This specification allows both international usernames and realms. This specification allows both international usernames and realms.
International usernames are based on the use of Unicode characters, International usernames are based on the use of Unicode characters,
encoded as UTF-8 and processed with a certain algorithm to ensure a encoded as UTF-8 and processed with a certain algorithm to ensure a
canonical representation. The realm part internationalization is canonical representation. The realm part internationalization is
based on International Domain Name (IDN) [4]. based on International Domain Name (IDN) [RFC3490].
In order to ensure a canonical representation, characters of the In order to ensure a canonical representation, characters of the
username portion in an NAI MUST fulfill the requirements specified in username portion in an NAI MUST fulfill the requirements specified in
[5]. In addition, the use of certain special characters (see grammar [I-D.ietf-sasl-saslprep]. In addition, the use of certain special
rule c) are prohibited as well in order to retain compatibility with characters (see grammar rule c) are prohibited as well in order to
the previous version of this RFC. retain compatibility with the previous version of this RFC.
The realm name is an "IDN-unaware domain name slot" as defined in The realm name is an "IDN-unaware domain name slot" as defined in
[4]. That is, it can contain only ASCII characters. An [RFC3490]. That is, it can contain only ASCII characters. An
implementation MAY support internationalized domain names (IDNs) implementation MAY support internationalized domain names (IDNs)
using the ToASCII operation; see [4] for more information. using the ToASCII operation; see [RFC3490] for more information.
2.5 Compatibility with E-Mail Usernames 2.5 Compatibility with E-Mail Usernames
As proposed in this document, the Network Access Identifier is of the As proposed in this document, the Network Access Identifier is of the
form user@realm. Please note that while the user portion of the NAI form user@realm. Please note that while the user portion of the NAI
is based on the BNF described in [6], it has been extended for is based on the BNF described in [RFC0821], it has been extended for
internationalization support as well as for purposes of Section 2.7, internationalization support as well as for purposes of Section 2.7,
and is not necessarily compatible with the usernames used in e-mail. and is not necessarily compatible with the usernames used in e-mail.
Note also that the internationalization requirements for NAIs and Note also that the internationalization requirements for NAIs and
e-mail addresses are different, since the former need to be typed in e-mail addresses are different, since the former need to be typed in
only by the user himself and his own operator, not by others. only by the user himself and his own operator, not by others.
2.6 Compatibility with DNS 2.6 Compatibility with DNS
The BNF of the realm portion allows the realm to begin with a digit, The BNF of the realm portion allows the realm to begin with a digit,
which is not permitted by the BNF described in [1]. This change was which is not permitted by the BNF described in [RFC1035]. This
made to reflect current practice; although not permitted by the BNF change was made to reflect current practice; although not permitted
described in [1], FQDNs such as 3com.com are commonly used, and by the BNF described in [RFC1035], FQDNs such as 3com.com are
accepted by current software. commonly used, and accepted by current software.
2.7 Realm Construction 2.7 Realm Construction
NAIs are used, among other purposes, for routing AAA transactions to NAIs are used, among other purposes, for routing AAA transactions to
the user's home realm. Usually, the home realm appears in the realm the user's home realm. Usually, the home realm appears in the realm
portion of the NAI, but in some cases a different realm can be used. portion of the NAI, but in some cases a different realm can be used.
This may be useful, for instance, when the home realm is only This may be useful, for instance, when the home realm is only
reachable via another mediating realm. reachable via another mediating realm.
Such usage may prevent interoperability unless the parties involved Such usage may prevent interoperability unless the parties involved
skipping to change at page 9, line 14 skipping to change at page 9, line 28
user@homerealm.example.net user@homerealm.example.net
2.8 Examples 2.8 Examples
Examples of valid Network Access Identifiers include: Examples of valid Network Access Identifiers include:
bob bob
joe@example.com joe@example.com
fred@foo-9.example.com fred@foo-9.example.com
jack@3rd.depts.example.com jack@3rd.depts.example.com
fred.smith@example.com
fred_smith@example.com fred_smith@example.com
fred$@example.com
fred=?#$&*+-/^smith@example.com fred=?#$&*+-/^smith@example.com
nancy@eng.example.net nancy@eng.example.net
eng.example.net!nancy@example.net eng.example.net!nancy@example.net
eng%nancy@example.net eng%nancy@example.net
@privatecorp.example.net @privatecorp.example.net
alice@xn--tmonesimerkki-bfbb.example.net alice@xn--tmonesimerkki-bfbb.example.net
\(user\)@example.net
The last example uses an IDN converted into an ASCII representation. The last example uses an IDN converted into an ASCII representation.
Examples of invalid Network Access Identifiers include: Examples of invalid Network Access Identifiers include:
fred@foo fred@example
fred@foo_9.com fred@example_9.com
fred@bigco.com@example.net fred@example.net@example.net
fred.@example.net
eng:nancy@example.net eng:nancy@example.net
eng;nancy@example.net eng;nancy@example.net
(user)@example.net
<nancy>@example.net <nancy>@example.net
3. Security Considerations 3. Security Considerations
Since an NAI reveals the home affiliation of a user, it may assist an Since an NAI reveals the home affiliation of a user, it may assist an
attacker in further probing the username space. Typically this attacker in further probing the username space. Typically this
problem is of most concern in protocols which transmit the user name problem is of most concern in protocols which transmit the user name
in clear-text across the Internet, such as in RADIUS, described in in clear-text across the Internet, such as in RADIUS, described in
[9] and [10]. In order to prevent snooping of the user name, [RFC2865] and [RFC2866]. In order to prevent snooping of the user
protocols may use confidentiality services provided by protocols name, protocols may use confidentiality services provided by
transporting them, such RADIUS protected by IPsec [11] or Diameter protocols transporting them, such RADIUS protected by IPsec [RFC3579]
protected by TLS [12]. or Diameter protected by TLS [RFC3588].
This specification adds the possibility of hiding the username part This specification adds the possibility of hiding the username part
in the NAI, by omitting it. As discussed in Section 2.3, this is in the NAI, by omitting it. As discussed in Section 2.3, this is
possible only when NAIs are used together with a separate possible only when NAIs are used together with a separate
authentication method that can transfer the username in a secure authentication method that can transfer the username in a secure
manner. In some cases application-specific privacy mechanism have manner. In some cases application-specific privacy mechanism have
also been used with NAIs. For instance, some EAP methods apply a also been used with NAIs. For instance, some EAP methods apply a
method-specific pseudonyms in the username part of the NAI. While method-specific pseudonyms in the username part of the NAI. While
neither of these approaches can protect the realm part, their neither of these approaches can protect the realm part, their
advantage over transport protection is that privacy of the username advantage over transport protection is that privacy of the username
skipping to change at page 11, line 21 skipping to change at page 10, line 43
NAI realm names are required to be unique and the rights to use a NAI realm names are required to be unique and the rights to use a
given NAI realm for roaming purposes are obtained coincident with given NAI realm for roaming purposes are obtained coincident with
acquiring the rights to use a particular fully qualified domain name acquiring the rights to use a particular fully qualified domain name
(FQDN). Those wishing to use an NAI realm name should first acquire (FQDN). Those wishing to use an NAI realm name should first acquire
the rights to use the corresponding FQDN. Using an NAI realm without the rights to use the corresponding FQDN. Using an NAI realm without
ownership of the corresponding FQDN creates the possibility of ownership of the corresponding FQDN creates the possibility of
conflict and therefore is to be discouraged. conflict and therefore is to be discouraged.
Note that the use of an FQDN as the realm name does not require use Note that the use of an FQDN as the realm name does not require use
of the DNS for location of the authentication server. While Diameter of the DNS for location of the authentication server. While Diameter
[12] supports the use of DNS for location of authentication servers, [RFC3588] supports the use of DNS for location of authentication
existing RADIUS implementations typically use proxy configuration servers, existing RADIUS implementations typically use proxy
files in order to locate authentication servers within a domain and configuration files in order to locate authentication servers within
perform authentication routing. The implementations described in [7] a domain and perform authentication routing. The implementations
did not use DNS for location of the authentication server within a described in [RFC2194] did not use DNS for location of the
domain. Similarly, existing implementations have not found a need authentication server within a domain. Similarly, existing
for dynamic routing protocols, or propagation of global routing implementations have not found a need for dynamic routing protocols,
information. Note also that there is no requirement that that the or propagation of global routing information. Note also that there
NAI represent a valid email address. is no requirement that that the NAI represent a valid email address.
5. References 5. References
5.1 Normative References 5.1 Normative References
[1] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[3] Crocker, D. and P. Overell, "Augmented BNF for Syntax [RFC2234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997. Specifications: ABNF", RFC 2234, November 1997.
[4] Faltstrom, P., Hoffman, P. and A. Costello, "Internationalizing [RFC3490] Faltstrom, P., Hoffman, P. and A. Costello,
Domain Names in Applications (IDNA)", RFC 3490, March 2003. "Internationalizing Domain Names in Applications (IDNA)",
RFC 3490, March 2003.
[5] Zeilenga, K., "SASLprep: Stringprep profile for user names and [I-D.ietf-sasl-saslprep]
passwords", draft-ietf-sasl-saslprep-04 (work in progress), Zeilenga, K., "SASLprep: Stringprep profile for user names
October 2003. and passwords", draft-ietf-sasl-saslprep-10 (work in
progress), July 2004.
5.2 Informative References 5.2 Informative References
[6] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC 821, [RFC0821] Postel, J., "Simple Mail Transfer Protocol", STD 10, RFC
August 1982. 821, August 1982.
[7] Aboba, B., Lu, J., Alsop, J., Ding, J. and W. Wang, "Review of [RFC2194] Aboba, B., Lu, J., Alsop, J., Ding, J. and W. Wang,
Roaming Implementations", RFC 2194, September 1997. "Review of Roaming Implementations", RFC 2194, September
1997.
[8] Aboba, B. and M. Beadles, "The Network Access Identifier", RFC [RFC2486] Aboba, B. and M. Beadles, "The Network Access Identifier",
2486, January 1999. RFC 2486, January 1999.
[9] Rigney, C., Willens, S., Rubens, A. and W. Simpson, "Remote [RFC2865] Rigney, C., Willens, S., Rubens, A. and W. Simpson,
Authentication Dial In User Service (RADIUS)", RFC 2865, June "Remote Authentication Dial In User Service (RADIUS)", RFC
2000. 2865, June 2000.
[10] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000. [RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.
[11] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial [RFC3579] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication
In User Service) Support For Extensible Authentication Protocol Dial In User Service) Support For Extensible
(EAP)", RFC 3579, September 2003. Authentication Protocol (EAP)", RFC 3579, September 2003.
[12] Calhoun, P., Loughney, J., Guttman, E., Zorn, G. and J. Arkko, [RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G. and J.
"Diameter Base Protocol", RFC 3588, September 2003. Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
[13] Arkko, J. and B. Aboba, "Network Discovery and Selection within [I-D.ietf-eap-netsel-problem]
the EAP Framework", draft-ietf-eap-netsel-problem-00 (work in Arkko, J. and B. Aboba, "Network Discovery and Selection
progress), January 2004. within the EAP Framework",
draft-ietf-eap-netsel-problem-02 (work in progress),
October 2004.
Authors' Addresses Authors' Addresses
Bernard Aboba Bernard Aboba
Microsoft Microsoft
One Microsoft Way One Microsoft Way
Redmond, WA 98052 Redmond, WA 98052
USA USA
EMail: bernarda@microsoft.com EMail: bernarda@microsoft.com
skipping to change at page 14, line 8 skipping to change at page 12, line 45
Nokia Research Center Nokia Research Center
P.O. Box 407 P.O. Box 407
FIN-00045 Nokia Group FIN-00045 Nokia Group
Finland Finland
EMail: pasi.eronen@nokia.com EMail: pasi.eronen@nokia.com
Appendix A. Changes from RFC 2486 Appendix A. Changes from RFC 2486
This draft contains the following updates with respect to the This draft contains the following updates with respect to the
original NAI definition in RFC 2486: original NAI definition in RFC 2486 [RFC2486]:
o International character set support has been added for both o International character set support has been added for both
usernames and realms. Note that this implies character codes 128 usernames and realms. Note that this implies character codes 128
- 255 may be used in the username portion, which may be - 255 may be used in the username portion, which may be
unacceptable to nodes that only support RFC 2486. Many devices unacceptable to nodes that only support RFC 2486. Many devices
already allow this behaviour, however. already allow this behaviour, however.
o Username privacy support has been added. Note that NAIs without a o Username privacy support has been added. Note that NAIs without a
username (for privacy) may not be acceptable to RFC 2486 compliant username (for privacy) may not be acceptable to RFC 2486 compliant
nodes. Many devices already allow this behaviour, however. nodes. Many devices already allow this behaviour, however.
o A recommendation to support NAI length of at least 253 octets has o A recommendation to support NAI length of at least 253 octets has
been added, and compatibility considerations among NAI lengths in been added, and compatibility considerations among NAI lengths in
this specification and various AAA protocols are discussed. Note this specification and various AAA protocols are discussed. Note
that long NAIs may not be acceptable to RFC 2486 compliant nodes. that long NAIs may not be acceptable to RFC 2486 compliant nodes.
o The mediating network syntax and its implications have been fully o The mediating network syntax and its implications have been fully
described and not given only as an example. Note that this syntax described and not given only as an example. Note that this syntax
is not intended to be a full solution to network discovery and is not intended to be a full solution to network discovery and
selection needs as defined in [13]. Rather, it is intended as a selection needs as defined in [I-D.ietf-eap-netsel-problem].
clarification of RFC 2486. Rather, it is intended as a clarification of RFC 2486.
However, as discussed in Section 2.7, this specification requires However, as discussed in Section 2.7, this specification requires
that this syntax be applied only when there is explicit knowledge that this syntax be applied only when there is explicit knowledge
that the peer system supports such syntax. that the peer system supports such syntax.
o The realm BNF entry definition has been changed to avoid an error o The realm BNF entry definition has been changed to avoid an error
(infinite recursion) in the original specification. (infinite recursion) in the original specification.
o Several clarifications and improvements have been incorporated to o Several clarifications and improvements have been incorporated to
the ABNF specification for NAIs. the ABNF specification for NAIs.
Appendix B. Acknowledgements Appendix B. Acknowledgements
Thanks to Glen Zorn for many useful discussions of this problem Thanks to Glen Zorn for many useful discussions of this problem
space, and for Farid Adrangi and others for suggesting mediating space, and for Farid Adrangi and others for suggesting mediating
network representation in NAIs. Jonathan Rosenberg reported the BNF network representation in NAIs. Jonathan Rosenberg reported the BNF
error. Dale Worley suggested clarifications of the x and special BNF error. Dale Worley suggested clarifications of the x and special BNF
entries. Arne Norefors reported the length differences between RFC entries. Arne Norefors reported the length differences between RFC
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/