draft-ietf-radext-dynamic-discovery-15.txt   rfc7585.txt 
RADIUS Extensions Working Group S. Winter Internet Engineering Task Force (IETF) S. Winter
Internet-Draft RESTENA Request for Comments: 7585 RESTENA
Intended status: Experimental M. McCauley Category: Experimental M. McCauley
Expires: November 1, 2015 AirSpayce ISSN: 2070-1721 AirSpayce
April 30, 2015 October 2015
NAI-based Dynamic Peer Discovery for RADIUS/TLS and RADIUS/DTLS Dynamic Peer Discovery for RADIUS/TLS and RADIUS/DTLS
draft-ietf-radext-dynamic-discovery-15 Based on the Network Access Identifier (NAI)
Abstract Abstract
This document specifies a means to find authoritative RADIUS servers This document specifies a means to find authoritative RADIUS servers
for a given realm. It is used in conjunction with either RADIUS/TLS for a given realm. It is used in conjunction with either RADIUS over
and RADIUS/DTLS. Transport Layer Security (RADIUS/TLS) or RADIUS over Datagram
Transport Layer Security (RADIUS/DTLS).
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for examination, experimental implementation, and
evaluation.
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 This document defines an Experimental Protocol for the Internet
and may be updated, replaced, or obsoleted by other documents at any community. This document is a product of the Internet Engineering
time. It is inappropriate to use Internet-Drafts as reference Task Force (IETF). It represents the consensus of the IETF
material or to cite them other than as "work in progress." community. It has received public review and has been approved for
publication by the Internet Engineering Steering Group (IESG). Not
all documents approved by the IESG are a candidate for any level of
Internet Standard; see Section 2 of RFC 5741.
This Internet-Draft will expire on November 1, 2015. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7585.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6
1.3. Document Status . . . . . . . . . . . . . . . . . . . . . 6 1.3. Document Status . . . . . . . . . . . . . . . . . . . . . 6
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 7 2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1. DNS Resource Record (RR) definition . . . . . . . . . . . 7 2.1. DNS Resource Record (RR) Definition . . . . . . . . . . . 7
2.1.1. S-NAPTR . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.1. S-NAPTR . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.2. SRV . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1.2. SRV . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.1.3. Optional name mangling . . . . . . . . . . . . . . . 12 2.1.3. Optional Name Mangling . . . . . . . . . . . . . . . 12
2.2. Definition of the X.509 certificate property 2.2. Definition of the X.509 Certificate Property
SubjectAltName:otherName:NAIRealm . . . . . . . . . . . . 13 SubjectAltName:otherName:NAIRealm . . . . . . . . . . . . 14
3. DNS-based NAPTR/SRV Peer Discovery . . . . . . . . . . . . . 15 3. DNS-Based NAPTR/SRV Peer Discovery . . . . . . . . . . . . . 16
3.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 15 3.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 16
3.2. Configuration Variables . . . . . . . . . . . . . . . . . 16 3.2. Configuration Variables . . . . . . . . . . . . . . . . . 16
3.3. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.3. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.4. Realm to RADIUS server resolution algorithm . . . . . . . 17 3.4. Realm to RADIUS Server Resolution Algorithm . . . . . . . 17
3.4.1. Input . . . . . . . . . . . . . . . . . . . . . . . . 17 3.4.1. Input . . . . . . . . . . . . . . . . . . . . . . . . 17
3.4.2. Output . . . . . . . . . . . . . . . . . . . . . . . 18 3.4.2. Output . . . . . . . . . . . . . . . . . . . . . . . 18
3.4.3. Algorithm . . . . . . . . . . . . . . . . . . . . . . 18 3.4.3. Algorithm . . . . . . . . . . . . . . . . . . . . . . 18
3.4.4. Validity of results . . . . . . . . . . . . . . . . . 19 3.4.4. Validity of Results . . . . . . . . . . . . . . . . . 20
3.4.5. Delay considerations . . . . . . . . . . . . . . . . 20 3.4.5. Delay Considerations . . . . . . . . . . . . . . . . 21
3.4.6. Example . . . . . . . . . . . . . . . . . . . . . . . 21 3.4.6. Example . . . . . . . . . . . . . . . . . . . . . . . 21
4. Operations and Manageability Considerations . . . . . . . . . 23 4. Operations and Manageability Considerations . . . . . . . . . 24
5. Security Considerations . . . . . . . . . . . . . . . . . . . 24 5. Security Considerations . . . . . . . . . . . . . . . . . . . 25
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 25 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 26
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 27
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.1. Normative References . . . . . . . . . . . . . . . . . . 28 8.1. Normative References . . . . . . . . . . . . . . . . . . 29
8.2. Informative References . . . . . . . . . . . . . . . . . 29 8.2. Informative References . . . . . . . . . . . . . . . . . 30
Appendix A. Appendix A: ASN.1 Syntax of NAIRealm . . . . . . . . 30 Appendix A. ASN.1 Syntax of NAIRealm . . . . . . . . . . . . . . 31
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32
1. Introduction 1. Introduction
RADIUS in all its current transport variants (RADIUS/UDP, RADIUS/TCP, RADIUS in all its current transport variants (RADIUS/UDP, RADIUS/TCP,
RADIUS/TLS, RADIUS/DTLS) requires manual configuration of all peers RADIUS/TLS, and RADIUS/DTLS) requires manual configuration of all
(clients, servers). peers (clients and servers).
Where more than one administrative entity collaborates for RADIUS Where more than one administrative entity collaborates for RADIUS
authentication of their respective customers (a "roaming authentication of their respective customers (a "roaming
consortium"), the Network Access Identifier (NAI) consortium"), the Network Access Identifier (NAI) [RFC7542] is the
[I-D.ietf-radext-nai] is the suggested way of differentiating users suggested way of differentiating users between those entities; the
between those entities; the part of a username to the right of the @ part of a username to the right of the "@" delimiter in an NAI is
delimiter in an NAI is called the user's "realm". Where many realms called the user's "realm". Where many realms and RADIUS forwarding
and RADIUS forwarding servers are in use, the number of realms to be servers are in use, the number of realms to be forwarded and the
forwarded and the corresponding number of servers to configure may be corresponding number of servers to configure may be significant.
significant. Where new realms with new servers are added or details Where new realms with new servers are added or details of existing
of existing servers change on a regular basis, maintaining a single servers change on a regular basis, maintaining a single monolithic
monolithic configuration file for all these details may prove too configuration file for all these details may prove too cumbersome to
cumbersome to be useful. be useful.
Furthermore, in cases where a roaming consortium consists of Furthermore, in cases where a roaming consortium consists of
independently working branches (e.g. departments, national independently working branches (e.g., departments and national
subsidiaries), each with their own forwarding servers, and who add or subsidiaries), each with their own forwarding servers, and who add or
change their realm lists at their own discretion, there is additional change their realm lists at their own discretion, there is additional
complexity in synchronising the changed data across all branches. complexity in synchronizing the changed data across all branches.
Where realms can be partitioned (e.g. according to their top-level Where realms can be partitioned (e.g., according to their top-level
domain ending), forwarding of requests can be realised with a domain (TLD) ending), forwarding of requests can be realized with a
hierarchy of RADIUS servers, all serving their partition of the realm hierarchy of RADIUS servers, all serving their partition of the realm
space. Figure 1 show an example of this hierarchical routing. space. Figure 1 shows an example of this hierarchical routing.
+-------+ +-------+
| | | |
| . | | . |
| | | |
+---+---+ +---+---+
/ | \ / | \
+----------------/ | \---------------------+ +----------------/ | \---------------------+
| | | | | |
| | | | | |
skipping to change at page 4, line 38 skipping to change at page 4, line 38
|utk.edu| |utah.edu| |case.edu| |hva.nl| |surfnet.nl| |soton.ac.uk| |utk.edu| |utah.edu| |case.edu| |hva.nl| |surfnet.nl| |soton.ac.uk|
| | | | | | | | | | | | | | | | | | | | | | | |
+----+--+ +--------+ +--------+ +------+ +----+-----+ +-----------+ +----+--+ +--------+ +--------+ +------+ +----+-----+ +-----------+
| | | |
| | | |
+--+--+ +--+--+ +--+--+ +--+--+
| | | | | | | |
+-+-----+-+ | | +-+-----+-+ | |
| | +-----+ | | +-----+
+---------+ +---------+
user: paul@surfnet.nl surfnet.nl Authentication server user: paul@surfnet.nl surfnet.nl Authentication server
Figure 1: RADIUS hierarchy based on Top-Level Domain partitioning Figure 1: RADIUS Hierarchy Based on Top-Level Domain Partitioning
However, such partitioning is not always possible. As an example, in However, such partitioning is not always possible. As an example, in
one real-life deployment, the administrative boundaries and RADIUS one real-life deployment, the administrative boundaries and RADIUS
forwarding servers are are organised along country borders, but forwarding servers are organized along country borders, but generic
generic top-level domains such as .edu do not map to this choice of top-level domains such as .edu do not map to this choice of
boundaries (see [I-D.wierenga-ietf-eduroam] for details). These boundaries (see [RFC7593] for details). These situations can benefit
situations can benefit significantly from a distributed mechanism for significantly from a distributed mechanism for storing realm and
storing realm and server reachability information. This document server reachability information. This document describes one such
describes one such mechanism: storage of realm-to-server mappings in mechanism: storage of realm-to-server mappings in DNS; realm-based
DNS; realm-based request forwarding can then be realised without a request forwarding can then be realized without a static hierarchy
static hierarchy such as in the following figure: such as in the following figure:
--------- ---------
/ \ / \
--------- ------------ --------- ------------
/ \ / \
| DNS - | DNS -
----------| \ ----------| \
/ \ surfnet.nl NAPTR? | / \ surfnet.nl NAPTR? |
(1) / ---- -> radius.surfnet.nl / (1) / ---- -> radius.surfnet.nl /
/ \ / / \ /
skipping to change at page 5, line 34 skipping to change at page 5, line 34
+----+--+ +--------+ +--------+ +------+ +----+-----+ +-----------+ +----+--+ +--------+ +--------+ +------+ +----+-----+ +-----------+
| | | |
| | | |
+--+--+ +--+--+ +--+--+ +--+--+
| | | | | | | |
+-+-----+-+ | | +-+-----+-+ | |
| | +-----+ | | +-----+
+---------+ +---------+
user: paul@surfnet.nl surfnet.nl Authentication server user: paul@surfnet.nl surfnet.nl Authentication server
Figure 2: RADIUS hierarchy based on Top-Level Domain partitioning Figure 2: RADIUS Hierarchy Based on Top-Level Domain Partitioning
This document also specifies various approaches for verifying that This document also specifies various approaches for verifying that
server information which was retrieved from DNS was from an server information that was retrieved from DNS was from an authorized
authorised party; e.g. an organisation which is not at all part of a party; for example, an organization that is not at all part of a
given roaming consortium may alter its own DNS records to yield a given roaming consortium may alter its own DNS records to yield a
result for its own realm. result for its own realm.
1.1. Requirements Language 1.1. Requirements Language
In this document, several words are used to signify the requirements In this document, several words are used to signify the requirements
of the specification. The key words "MUST", "MUST NOT", "REQUIRED", of the specification. The key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" in this document are to be interpreted as described in and "OPTIONAL" in this document are to be interpreted as described in
RFC 2119. [RFC2119] RFC 2119 [RFC2119].
1.2. Terminology 1.2. Terminology
RADIUS/TLS Client: a RADIUS/TLS [RFC6614] instance which initiates a RADIUS/TLS Client: a RADIUS/TLS [RFC6614] instance that initiates a
new connection. new connection.
RADIUS/TLS Server: a RADIUS/TLS [RFC6614] instance which listens on a RADIUS/TLS Server: a RADIUS/TLS [RFC6614] instance that listens on a
RADIUS/TLS port and accepts new connections RADIUS/TLS port and accepts new connections.
RADIUS/TLS node: a RADIUS/TLS client or server RADIUS/TLS Node: a RADIUS/TLS client or server.
[I-D.ietf-radext-nai] defines the terms NAI, realm, consortium. [RFC7542] defines the terms NAI, realm, and consortium.
1.3. Document Status 1.3. Document Status
This document is an Experimental RFC. This document is an Experimental RFC.
The communities expected to use this document are roaming consortia The communities expected to use this document are roaming consortia
whose authentication services are based on the RADIUS protocol. whose authentication services are based on the RADIUS protocol.
The duration of the experiment is undetermined; as soon as enough The duration of the experiment is undetermined; as soon as enough
experience is collected on the choice points mentioned below, it is experience is collected on the choice points mentioned below, it is
expected to be obsoleted by a standards-track version of the protocol expected to be obsoleted by a Standards Track version of the
which trims down the choice points. protocol, which trims down the choice points.
If that removal of choice points obsoletes tags or service names as If that removal of choice points obsoletes tags or service names as
defined in this document and allocated by IANA, these items will be defined in this document and allocated by IANA, these items will be
returned to IANA as per the provisions in [RFC6335]. returned to IANA as per the provisions in [RFC6335].
The document provides a discovery mechanism for RADIUS which is very The document provides a discovery mechanism for RADIUS, which is very
similar to the approach that is taken with the Diameter protocol similar to the approach that is taken with the Diameter protocol
[RFC6733]. As such, the basic approach (using Naming Authority [RFC6733]. As such, the basic approach (using Naming Authority
Pointer (NAPTR) records in DNS domains which match NAI realms) is not Pointer (NAPTR) records in DNS domains that match NAI realms) is not
of very experimental nature. of a very experimental nature.
However, the document offers a few choice points and extensions which However, the document offers a few choice points and extensions that
go beyond the provisions for Diameter. The list of major additions/ go beyond the provisions for Diameter. The list of major additions/
deviations is deviations is
o provisions for determining the authority of a server to act for o provisions for determining the authority of a server to act for
users of a realm (declared out of scope for Diameter) users of a realm (declared out of scope for Diameter)
o much more in-depth guidance on DNS regarding timeouts, failure o much more in-depth guidance on DNS regarding timeouts, failure
conditions, alteration of Time-To-Live (TTL) information than the conditions, and alteration of Time-To-Live (TTL) information than
Diameter counterpart the Diameter counterpart
o a partially correct routing error detection during DNS lookups o a partially correct routing error detection during DNS lookups
2. Definitions 2. Definitions
2.1. DNS Resource Record (RR) definition 2.1. DNS Resource Record (RR) Definition
DNS definitions of RADIUS/TLS servers can be either S-NAPTR records DNS definitions of RADIUS/TLS servers can be either S-NAPTR records
(see [RFC3958]) or Service Record (SRV) records. When both are (see [RFC3958]) or SRV records. When both are defined, the
defined, the resolution algorithm prefers S-NAPTR results (see resolution algorithm prefers S-NAPTR results (see Section 3.4 below).
Section 3.4 below).
2.1.1. S-NAPTR 2.1.1. S-NAPTR
2.1.1.1. Registration of Application Service and Protocol Tags 2.1.1.1. Registration of Application Service and Protocol Tags
This specification defines three S-NAPTR service tags: This specification defines three S-NAPTR service tags:
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
| Service Tag | Use | | Service Tag | Use |
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
| aaa+auth | RADIUS Authentication, i.e. traffic as | | aaa+auth | RADIUS Authentication, i.e., traffic as |
| | defined in [RFC2865] | | | defined in [RFC2865] |
| - - - - - - - - | - - - - - - - - - - - - - - - - - - - - | | - - - - - - - - | - - - - - - - - - - - - - - - - - - - - |
| aaa+acct | RADIUS Accounting, i.e. traffic as | | aaa+acct | RADIUS Accounting, i.e., traffic as |
| | defined in [RFC2866] | | | defined in [RFC2866] |
| - - - - - - - - | - - - - - - - - - - - - - - - - - - - - | | - - - - - - - - | - - - - - - - - - - - - - - - - - - - - |
| aaa+dynauth | RADIUS Dynamic Authorisation, i.e. | | aaa+dynauth | RADIUS Dynamic Authorization, i.e., |
| | traffic as defined in [RFC5176] | | | traffic as defined in [RFC5176] |
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
Figure 3: List of Service Tags Figure 3: List of Service Tags
This specification defines two S-NAPTR protocol tags: This specification defines two S-NAPTR protocol tags:
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
| Protocol Tag | Use | | Protocol Tag | Use |
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
skipping to change at page 8, line 6 skipping to change at page 7, line 51
| - - - - - - - - | - - - - - - - - - - - - - - - - - - - - | | - - - - - - - - | - - - - - - - - - - - - - - - - - - - - |
| radius.dtls.udp | RADIUS transported over DTLS as defined | | radius.dtls.udp | RADIUS transported over DTLS as defined |
| | in [RFC7360] | | | in [RFC7360] |
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
Figure 4: List of Protocol Tags Figure 4: List of Protocol Tags
Note well: Note well:
The S-NAPTR service and protocols are unrelated to the IANA The S-NAPTR service and protocols are unrelated to the IANA
Service Name and Transport Protocol Number registry. "Service Name and Transport Protocol Port Number Registry".
The delimiter '.' in the protocol tags is only a separator for The delimiter "." in the protocol tags is only a separator for
human reading convenience - not for structure or namespacing; it human reading convenience -- not for structure or namespacing; it
MUST NOT be parsed in any way by the querying application or MUST NOT be parsed in any way by the querying application or
resolver. resolver.
The use of the separator '.' is common also in other protocols' The use of the separator "." is common also in other protocols'
protocol tags. This is coincidence and does not imply a shared protocol tags. This is coincidence and does not imply a shared
semantics with such protocols. semantics with such protocols.
2.1.1.2. Definition of Conditions for Retry/Failure 2.1.1.2. Definition of Conditions for Retry/Failure
RADIUS is a time-critical protocol; RADIUS clients which do not RADIUS is a time-critical protocol; RADIUS clients that do not
receive an answer after a configurable, but short, amount of time, receive an answer after a configurable, but short, amount of time
will consider the request failed. Due to this, there is little will consider the request failed. Due to this, there is little
leeway for extensive retries. leeway for extensive retries.
As a general rule, only error conditions which generate an immediate As a general rule, only error conditions that generate an immediate
response from the other end are eligible for a retry of a discovered response from the other end are eligible for a retry of a discovered
target. Any error condition involving timeouts, or the absence of a target. Any error condition involving timeouts, or the absence of a
reply for more than one second during the connection setup phase is reply for more than one second during the connection setup phase, is
to be considered a failure; the next target in the set of discovered to be considered a failure; the next target in the set of discovered
NAPTR targets is to be tried. NAPTR targets is to be tried.
Note that [RFC3958] already defines that a failure to identify the Note that [RFC3958] already defines that a failure to identify the
server as being authoritative for the realm is always considered a server as being authoritative for the realm is always considered a
failure; so even if a discovered target returns a wrong credential failure; so even if a discovered target returns a wrong credential
instantly, it is not eligible for retry. instantly, it is not eligible for retry.
Furthermore, the contacted RADIUS/TLS server verifies during Furthermore, the contacted RADIUS/TLS server verifies during
connection setup whether or not it finds the connecting RADIUS/TLS connection setup whether or not it finds the connecting RADIUS/TLS
client authorized or not. If the connecting RADIUS/TLS client is not client authorized. If the connecting RADIUS/TLS client is not found
found acceptable, the server will close the TLS connection acceptable, the server will close the TLS connection immediately with
immediately with an appropriate alert. Such TLS handshake failures an appropriate alert. Such TLS handshake failures are permanently
are permanently fatal and not eligible for retry, unless the fatal and not eligible for retry, unless the connecting client has
connecting client has more X.509 certificates to try; in this case, a more X.509 certificates to try; in this case, a retry with the
retry with the remainder of its set of certificates SHOULD be remainder of its set of certificates SHOULD be attempted. Not trying
attempted. Not trying all available client certificates potentially all available client certificates potentially creates a DoS for the
creates a DoS for the end-user whose authentication attempt triggered end user whose authentication attempt triggered the discovery; one of
the discovery; one of the neglected certificates might have led to a the neglected certificates might have led to a successful RADIUS
successful RADIUS connection and subsequent end-user authentication. connection and subsequent end-user authentication.
If the TLS session setup to a discovered target does not succeed, If the TLS session setup to a discovered target does not succeed,
that target (as identified by IP address and port number) SHOULD be that target (as identified by the IP address and port number) SHOULD
ignored from the result set of any subsequent executions of the be ignored from the result set of any subsequent executions of the
discovery algorithm at least until the target's Effective TTL (see discovery algorithm at least until the target's Effective TTL (see
Section 3.3) has expired or until the entity which executes the Section 3.3) has expired or until the entity that executes the
algorithm changes its TLS context to either send a new client algorithm changes its TLS context to either send a new client
certificate or expect a different server certificate. certificate or expect a different server certificate.
2.1.1.3. Server Identification and Handshake 2.1.1.3. Server Identification and Handshake
After the algorithm in this document has been executed, a RADIUS/TLS After the algorithm in this document has been executed, a RADIUS/TLS
session as per [RFC6614] is established. Since the dynamic discovery session as per [RFC6614] is established. Since the discovery
algorithm does not have provisions to establish confidential keying algorithm does not have provisions to establish confidential keying
material between the RADIUS/TLS client (i.e. the server which material between the RADIUS/TLS client (i.e., the server that
executes the discovery algorithm) and the RADIUS/TLS server which was executes the discovery algorithm) and the RADIUS/TLS server that was
discovered, TLS-PSK ciphersuites cannot be used in the subsequent TLS discovered, Pre-Shared Key (PSK) ciphersuites for TLS cannot be used
handshake. Only TLS ciphersuites using X.509 certificates can be in the subsequent TLS handshake. Only TLS ciphersuites using X.509
used with this algorithm. certificates can be used with this algorithm.
There are numerous ways to define which certificates are acceptable There are numerous ways to define which certificates are acceptable
for use in this context. This document defines one mandatory-to- for use in this context. This document defines one mandatory-to-
implement mechanism which allows to verify whether the contacted host implement mechanism that allows verification of whether the contacted
is authoritative for an NAI realm or not. It also gives one example host is authoritative for an NAI realm or not. It also gives one
of another mechanism which is currently in wide-spread deployment, example of another mechanism that is currently in widespread
and one possible approach based on DNSSEC which is yet unimplemented. deployment and one possible approach based on DNSSEC, which is yet
unimplemented.
For the approaches which use trust roots (see the following two For the approaches that use trust roots (see the following two
sections), a typical deployment will use a dedicated trust store for sections), a typical deployment will use a dedicated trust store for
RADIUS/TLS certificate authorities, particularly a trust store which RADIUS/TLS certificate authorities, particularly a trust store that
is independent from default "browser" trust stores. Often, this will is independent from default "browser" trust stores. Often, this will
be one or few CAs, and they only issue certificates for the specific be one or a few Certification Authorities (CAs), and they only issue
purpose of establishing RADIUS server-to-server trust. It is certificates for the specific purpose of establishing RADIUS server-
important not to trust a large set of CAs which operate outside the to-server trust. It is important not to trust a large set of CAs
control of the roaming consortium, for their issuance of certificates that operate outside the control of the roaming consortium, since
with the properties important for authorisation (such as NAIRealm and their issuance of certificates with the properties important for
policyOID below) is difficult to verify. Therefore, clients SHOULD authorization (such as NAIRealm and policyOID below) is difficult to
NOT be pre-configured with a list of known public CAs by the vendor verify. Therefore, clients SHOULD NOT be preconfigured with a list
or manufacturer. Instead, the clients SHOULD start off with an empty of known public CAs by the vendor or manufacturer. Instead, the
CA list. The addition of a CA SHOULD be done only when manually clients SHOULD start off with an empty CA list. The addition of a CA
configured by an administrator. SHOULD be done only when manually configured by an administrator.
2.1.1.3.1. Mandatory-to-implement mechanism: Trust Roots + NAIRealm 2.1.1.3.1. Mandatory-to-Implement Mechanism: Trust Roots + NAIRealm
Verification of authority to provide AAA services over RADIUS/TLS is Verification of authority to provide Authentication, Authorization,
a two-step process. and Accounting (AAA) services over RADIUS/TLS is a two-step process.
Step 1 is the verification of certificate wellformedness and validity Step 1 is the verification of certificate well-formedness and
as per [RFC5280] and whether it was issued from a root certificate validity as per [RFC5280] and whether it was issued from a root
which is deemed trustworthy by the RADIUS/TLS client. certificate that is deemed trustworthy by the RADIUS/TLS client.
Step 2 is to compare the value of algorithm's variable "R" after the Step 2 is to compare the value of the algorithm's variable "R" after
execution of step 3 of the discovery algorithm in Section 3.4.3 below the execution of step 3 of the discovery algorithm in Section 3.4.3
(i.e. after a consortium name mangling, but before conversion to a below (i.e., after a consortium name mangling but before conversion
form usable by the name resolution library) to all values of the to a form usable by the name resolution library) to all values of the
contacted RADIUS/TLS server's X.509 certificate property contacted RADIUS/TLS server's X.509 certificate property
"subjectAlternativeName:otherName:NAIRealm" as defined in "subjectAlternativeName:otherName:NAIRealm" as defined in
Section 2.2. Section 2.2.
2.1.1.3.2. Other mechanism: Trust Roots + policyOID 2.1.1.3.2. Other Mechanism: Trust Roots + policyOID
Verification of authority to provide AAA services over RADIUS/TLS is Verification of authority to provide AAA services over RADIUS/TLS is
a two-step process. a two-step process.
Step 1 is the verification of certificate wellformedness and validity Step 1 is the verification of certificate well-formedness and
as per [RFC5280] and whether it was issued from a root certificate validity as per [RFC5280] and whether it was issued from a root
which is deemed trustworthy by the RADIUS/TLS client. certificate that is deemed trustworthy by the RADIUS/TLS client.
Step 2 is to compare the values of the contacted RADIUS/TLS server's Step 2 is to compare the values of the contacted RADIUS/TLS server's
X.509 certificate's extensions of type "Policy OID" to a list of X.509 certificate's extensions of type "Policy OID" to a list of
configured acceptable Policy OIDs for the roaming consortium. If one configured acceptable Policy OIDs for the roaming consortium. If one
of the configured OIDs is found in the certificate's Policy OID of the configured OIDs is found in the certificate's Policy OID
extensions, then the server is considered authorized; if there is no extensions, then the server is considered authorized; if there is no
match, the server is considered unauthorized. match, the server is considered unauthorized.
This mechanism is inferior to the mandatory-to-implement mechanism in This mechanism is inferior to the mandatory-to-implement mechanism in
the previous section because all authorized servers are validated by the previous section because all authorized servers are validated by
the same OID value; the mechanism is not fine-grained enough to the same OID value; the mechanism is not fine grained enough to
express authority for one specific realm inside the consortium. If express authority for one specific realm inside the consortium. If
the consortium contains members which are hostile against other the consortium contains members that are hostile against other
members, this weakness can be exploited by one RADIUS/TLS server members, this weakness can be exploited by one RADIUS/TLS server
impersonating another if DNS responses can be spoofed by the hostile impersonating another if DNS responses can be spoofed by the hostile
member. member.
The shortcomings in server identification can be partially mitigated The shortcomings in server identification can be partially mitigated
by using the RADIUS infrastructure only with authentication payloads by using the RADIUS infrastructure only with authentication payloads
which provide mutual authentication and credential protection (i.e. that provide mutual authentication and credential protection (i.e.,
EAP types passing the criteria of [RFC4017]): using mutual Extensible Authentication Protocol (EAP) types passing the criteria
authentication prevents the hostile server from mimicking the real of [RFC4017]): using mutual authentication prevents the hostile
EAP server (it can't terminate the EAP authentication unnoticed server from mimicking the real EAP server (it can't terminate the EAP
because it does not have the server certificate from the real EAP authentication unnoticed because it does not have the server
server); protection of credentials prevents the impersonating server certificate from the real EAP server); protection of credentials
from learning usernames and passwords of the ongoing EAP conversation prevents the impersonating server from learning usernames and
(other RADIUS attributes pertaining to the authentication, such as passwords of the ongoing EAP conversation (other RADIUS attributes
the EAP peer's Calling-Station-ID, can still be learned though). pertaining to the authentication, such as the EAP peer's Calling-
Station-ID, can still be learned though).
2.1.1.3.3. Other mechanism: DNSSEC / DANE 2.1.1.3.3. Other Mechanism: DNSSEC/DANE
Where DNSSEC is used, the results of the algorithm can be trusted; Where DNSSEC is used, the results of the algorithm can be trusted;
i.e. the entity which executes the algorithm can be certain that the that is, the entity that executes the algorithm can be certain that
realm that triggered the discovery is actually served by the server the realm that triggered the discovery is actually served by the
that was discovered via DNS. However, this does not guarantee that server that was discovered via DNS. However, this does not guarantee
the server is also authorized (i.e. a recognised member of the that the server is also authorized (i.e., a recognized member of the
roaming consortium). The server still needs to present an X.509 roaming consortium). The server still needs to present an X.509
certificate proving its authority to serve a particular realm. certificate proving its authority to serve a particular realm.
The authorization can be sketched using DNSSEC+DANE as follows: DANE/ The authorization can be sketched using DNSSEC and DNS-Based
TLSA records of all authorized servers are put into a DNSSEC zone Authentication of Named Entities (DANE) as follows: DANE/TLSA records
which contains all known and authorised realms; the zone is rooted in of all authorized servers are put into a DNSSEC zone that contains
a common, consortium-agreed branch of the DNS tree. The entity all known and authorized realms; the zone is rooted in a common,
executing the algorithm uses the realm information from the consortium-agreed branch of the DNS tree. The entity executing the
authentication attempt, and then attempts to retrieve TLSA Resource algorithm uses the realm information from the authentication attempt
Records (TLSA RR) for the DNS label "realm.commonroot". It then and then attempts to retrieve TLSA resource records (TLSA RRs) for
verifies that the presented server certificate during the RADIUS/TLS the DNS label "realm.commonroot". It then verifies that the
handshake matches the information in the TLSA record. presented server certificate during the RADIUS/TLS handshake matches
the information in the TLSA record.
Example: Example:
Realm = "example.com" Realm = "example.com"
Common Branch = "idp.roaming-consortium.example. Common Branch = "idp.roaming-consortium.example.
label for TLSA query = "example.com.idp.roaming- label for TLSA query = "example.com.idp.roaming-
consortium.example. consortium.example.
result of discovery algorithm for realm "example.com" = result of discovery algorithm for realm "example.com" =
192.0.2.1:2083 192.0.2.1:2083
( TLS certificate of 192.0.2.1:2083 matches TLSA RR ? "PASS" : ( TLS certificate of 192.0.2.1:2083 matches TLSA RR ? "PASS" :
"FAIL" ) "FAIL" )
2.1.1.3.4. Client Authentication and Authorisation 2.1.1.3.4. Client Authentication and Authorization
Note that RADIUS/TLS connections always mutually authenticate the Note that RADIUS/TLS connections always mutually authenticate the
RADIUS server and the RADIUS client. This specification provides an RADIUS server and the RADIUS client. This specification provides an
algorithm for a RADIUS client to contact and verify authorization of algorithm for a RADIUS client to contact and verify authorization of
a RADIUS server only. During connection setup, the RADIUS server a RADIUS server only. During connection setup, the RADIUS server
also needs to verify whether it considers the connecting RADIUS also needs to verify whether it considers the connecting RADIUS
client authorized; this is outside the scope of this specification. client authorized; this is outside the scope of this specification.
2.1.2. SRV 2.1.2. SRV
This specification defines two SRV prefixes (i.e. two values for the This specification defines two SRV prefixes (i.e., two values for the
"_service._proto" part of an SRV RR as per [RFC2782]): "_service._proto" part of an SRV RR as per [RFC2782]):
+-------------------+-----------------------------------------+ +-------------------+-----------------------------------------+
| SRV Label | Use | | SRV Label | Use |
+-------------------+-----------------------------------------+ +-------------------+-----------------------------------------+
| _radiustls._tcp | RADIUS transported over TLS as defined | | _radiustls._tcp | RADIUS transported over TLS as defined |
| | in [RFC6614] | | | in [RFC6614] |
| - - - - - - - - - | - - - - - - - - - - - - - - - - - - - - | | - - - - - - - - - | - - - - - - - - - - - - - - - - - - - - |
| _radiusdtls._udp | RADIUS transported over DTLS as defined | | _radiusdtls._udp | RADIUS transported over DTLS as defined |
| | in [RFC7360] | | | in [RFC7360] |
+-------------------+-----------------------------------------+ +-------------------+-----------------------------------------+
Figure 5: List of SRV Labels Figure 5: List of SRV Labels
Just like NAPTR records, the lookup and subsequent follow-up of SRV Just like NAPTR records, the lookup and subsequent follow up of SRV
records may yield more than one server to contact in a prioritised records may yield more than one server to contact in a prioritized
list. [RFC2782] does not specify rules regarding "Definition of list. [RFC2782] does not specify rules regarding "Definition of
Conditions for Retry/Failure", nor "Server Identification and Conditions for Retry/Failure" nor "Server Identification and
Handshake". This specification defines that the rules for these two Handshake". This specification states that the rules for these two
topics as defined in Section 2.1.1.2 and Section 2.1.1.3 SHALL be topics as defined in Sections 2.1.1.2 and 2.1.1.3 SHALL be used both
used both for targets retrieved via an initial NAPTR RR as well as for targets retrieved via an initial NAPTR RR as well as for targets
for targets retrieved via an initial SRV RR (i.e. in the absence of retrieved via an initial SRV RR (i.e., in the absence of NAPTR RRs).
NAPTR RRs).
2.1.3. Optional name mangling 2.1.3. Optional Name Mangling
It is expected that in most cases, the SRV and/or NAPTR label used It is expected that in most cases, the SRV and/or NAPTR label used
for the records is the DNS A-label representation of the literal for the records is the DNS A-label representation of the literal
realm name for which the server is the authoritative RADIUS server realm name for which the server is the authoritative RADIUS server
(i.e. the realm name after conversion according to section 5 of (i.e., the realm name after conversion according to Section 5 of
[RFC5891]). [RFC5891]).
However, arbitrary other labels or service tags may be used if, for However, arbitrary other labels or service tags may be used if, for
example, a roaming consortium uses realm names which are not example, a roaming consortium uses realm names that are not
associated to DNS names or special-purpose consortia where a globally associated to DNS names or special-purpose consortia where a globally
valid discovery is not a use case. Such other labels require a valid discovery is not a use case. Such other labels require a
consortium-wide agreement about the transformation from realm name to consortium-wide agreement about the transformation from realm name to
lookup label, and/or which service tag to use. lookup label and/or which service tag to use.
Examples: Examples:
a. A general-purpose RADIUS server for realm example.com might have a. A general-purpose RADIUS server for realm example.com might have
DNS entries as follows: DNS entries as follows:
example.com. IN NAPTR 50 50 "s" "aaa+auth:radius.tls.tcp" "" example.com. IN NAPTR 50 50 "s" "aaa+auth:radius.tls.tcp" ""
_radiustls._tcp.foobar.example.com. _radiustls._tcp.foobar.example.com.
_radiustls._tcp.foobar.example.com. IN SRV 0 10 2083 _radiustls._tcp.foobar.example.com. IN SRV 0 10 2083
radsec.example.com. radsec.example.com.
b. The consortium "foo" provides roaming services for its members b. The consortium "foo" provides roaming services for its members
only. The realms used are of the form enterprise-name.example. only. The realms used are of the form enterprise-name.example.
The consortium operates a special purpose DNS server for the The consortium operates a special purpose DNS server for the
(private) TLD "example" which all RADIUS servers use to resolve (private) TLD "example", which all RADIUS servers use to resolve
realm names. "Company, Inc." is part of the consortium. On the realm names. "Company, Inc." is part of the consortium. On the
consortium's DNS server, realm company.example might have the consortium's DNS server, realm company.example might have the
following DNS entries: following DNS entries:
company.example. IN NAPTR 50 50 "a" company.example. IN NAPTR 50 50 "a"
"aaa+auth:radius.dtls.udp" "" roamserv.company.example. "aaa+auth:radius.dtls.udp" "" roamserv.company.example.
c. The eduroam consortium (see [I-D.wierenga-ietf-eduroam] uses c. The eduroam consortium (see [RFC7593]) uses realms based on DNS
realms based on DNS, but provides its services to a closed but provides its services to a closed community only. However, a
community only. However, a AAA domain participating in eduroam AAA domain participating in eduroam may also want to expose AAA
may also want to expose AAA services to other, general-purpose, services to other, general-purpose, applications (on the same or
applications (on the same or other RADIUS servers). Due to that, other RADIUS servers). Due to that, the eduroam consortium uses
the eduroam consortium uses the service tag "x-eduroam" for the service tag "x-eduroam" for authentication purposes and
authentication purposes and eduroam RADIUS servers use this tag eduroam RADIUS servers use this tag to look up other eduroam
to look up other eduroam servers. An eduroam participant servers. An eduroam participant example.org that also provides
example.org which also provides general-purpose AAA on a general-purpose AAA on a different server uses the general
different server uses the general "aaa+auth" tag: "aaa+auth" tag:
example.org. IN NAPTR 50 50 "s" "x-eduroam:radius.tls.tcp" "" example.org. IN NAPTR 50 50 "s" "x-eduroam:radius.tls.tcp" ""
_radiustls._tcp.eduroam.example.org. _radiustls._tcp.eduroam.example.org.
example.org. IN NAPTR 50 50 "s" "aaa+auth:radius.tls.tcp" "" example.org. IN NAPTR 50 50 "s" "aaa+auth:radius.tls.tcp" ""
_radiustls._tcp.aaa.example.org. _radiustls._tcp.aaa.example.org.
_radiustls._tcp.eduroam.example.org. IN SRV 0 10 2083 aaa- _radiustls._tcp.eduroam.example.org. IN SRV 0 10 2083 aaa-
eduroam.example.org. eduroam.example.org.
_radiustls._tcp.aaa.example.org. IN SRV 0 10 2083 aaa- _radiustls._tcp.aaa.example.org. IN SRV 0 10 2083 aaa-
default.example.org. default.example.org.
2.2. Definition of the X.509 certificate property 2.2. Definition of the X.509 Certificate Property
SubjectAltName:otherName:NAIRealm SubjectAltName:otherName:NAIRealm
This specification retrieves IP addresses and port numbers from the This specification retrieves IP addresses and port numbers from the
Domain Name System which are subsequently used to authenticate users Domain Name System that are subsequently used to authenticate users
via the RADIUS/TLS protocol. Regardless whether the results from DNS via the RADIUS/TLS protocol. Regardless whether the results from DNS
discovery are trustworthy or not (e.g. DNSSEC in use), it is always discovery are trustworthy or not (e.g., DNSSEC in use), it is always
important to verify that the server which was contacted is authorized important to verify that the server that was contacted is authorized
to service requests for the user which triggered the discovery to service requests for the user that triggered the discovery
process. process.
The input to the algorithm is an NAI realm as specified in The input to the algorithm is an NAI realm as specified in
Section 3.4.1. As a consequence, the X.509 certificate of the server Section 3.4.1. As a consequence, the X.509 certificate of the server
which is ultimately contacted for user authentication needs to be that is ultimately contacted for user authentication needs to be able
able to express that it is authorized to handle requests for that to express that it is authorized to handle requests for that realm.
realm.
Current subjectAltName fields do not semantically allow to express an Current subjectAltName fields do not semantically allow an NAI realm
NAI realm; the field subjectAltName:dNSName is syntactically a good to be expressed; the field subjectAltName:dNSName is syntactically a
match but would inappropriately conflate DNS names and NAI realm good match but would inappropriately conflate DNS names and NAI realm
names. Thus, this specification defines a new subjectAltName field names. Thus, this specification defines a new subjectAltName field
to hold either a single NAI realm name or a wildcard name matching a to hold either a single NAI realm name or a wildcard name matching a
set of NAI realms. set of NAI realms.
The subjectAltName:otherName:sRVName field certifies that a The subjectAltName:otherName:sRVName field certifies that a
certificate holder is authorized to provide a service; this can be certificate holder is authorized to provide a service; this can be
compared to the target of DNS label's SRV resource record. If the compared to the target of a DNS label's SRV resource record. If the
Domain Name System is insecure, it is required that the label of the Domain Name System is insecure, it is required that the label of the
SRV record itself is known-correct. In this specification, that SRV record itself is known-correct. In this specification, that
label is not known-correct; it is potentially derived from a label is not known-correct; it is potentially derived from a
(potentially untrusted) NAPTR resource record of another label. If (potentially untrusted) NAPTR resource record of another label. If
DNS is not secured with DNSSEC, the NAPTR resource record may have DNS is not secured with DNSSEC, the NAPTR resource record may have
been altered by an attacker with access to the Domain Name System been altered by an attacker with access to the Domain Name System
resolution, and thus the label to lookup the SRV record for may resolution, and thus the label used to look up the SRV record may
already be tainted. This makes subjectAltName:otherName:sRVName not already be tainted. This makes subjectAltName:otherName:sRVName not
a trusted comparison item. a trusted comparison item.
Further to this, this specification's NAPTR entries may be of type Further to this, this specification's NAPTR entries may be of type
"A" which do not involve resolution of any SRV records, which again "A", which does not involve resolution of any SRV records, which
makes subjectAltName:otherName:sRVName unsuited for this purpose. again makes subjectAltName:otherName:sRVName unsuited for this
purpose.
This section defines the NAIRealm name as a form of otherName from This section defines the NAIRealm name as a form of otherName from
the GeneralName structure in SubjectAltName defined in [RFC5280]. the GeneralName structure in subjectAltName defined in [RFC5280].
id-on-naiRealm OBJECT IDENTIFIER ::= { id-on XXX } id-on-naiRealm OBJECT IDENTIFIER ::= { id-on 8 }
ub-naiRealm-length INTEGER ::= 255 ub-naiRealm-length INTEGER ::= 255
NAIRealm ::= UTF8String (SIZE (1..ub-naiRealm-length)) NAIRealm ::= UTF8String (SIZE (1..ub-naiRealm-length))
The NAIRealm, if present, MUST contain an NAI realm as defined in The NAIRealm, if present, MUST contain an NAI realm as defined in
[I-D.ietf-radext-nai]. It MAY substitute the leftmost dot-separated [RFC7542]. It MAY substitute the leftmost dot-separated label of the
label of the NAI with the single character "*" to indicate a wildcard NAI with the single character "*" to indicate a wildcard match for
match for "all labels in this part". Further features of regular "all labels in this part". Further features of regular expressions,
expressions, such as a number of characters followed by a * to such as a number of characters followed by an "*" to indicate a
indicate a common prefix inside the part, are not permitted. common prefix inside the part, are not permitted.
The comparison of an NAIRealm to the NAI realm as derived from user The comparison of an NAIRealm to the NAI realm as derived from user
input with this algorithm is a byte-by-byte comparison, except for input with this algorithm is a byte-by-byte comparison, except for
the optional leftmost dot-separated part of the value whose content the optional leftmost dot-separated part of the value whose content
is a single "*" character; such labels match all strings in the same is a single "*" character; such labels match all strings in the same
dot-separated part of the NAI realm. If at least one of the dot-separated part of the NAI realm. If at least one of the
sAN:otherName:NAIRealm values matches the NAI realm, the server is sAN:otherName:NAIRealm values match the NAI realm, the server is
considered authorized; if none matches, the server is considered considered authorized; if none match, the server is considered
unauthorized. unauthorized.
Since multiple names and multiple name forms may occur in the Since multiple names and multiple name forms may occur in the
subjectAltName extension, an arbitrary number of NAIRealms can be subjectAltName extension, an arbitrary number of NAIRealms can be
specified in a certificate. specified in a certificate.
Examples: Examples:
+---------------------+-------------------+-----------------------+ +---------------------+-------------------+-----------------------+
| NAI realm (RADIUS) | NAIRealm (cert) | MATCH? | | NAI realm (RADIUS) | NAIRealm (cert) | MATCH? |
skipping to change at page 15, line 27 skipping to change at page 15, line 46
| foo.example | foo.example | YES | | foo.example | foo.example | YES |
| foo.example | *.example | YES | | foo.example | *.example | YES |
| bar.foo.example | *.example | NO | | bar.foo.example | *.example | NO |
| bar.foo.example | *ar.foo.example | NO (NAIRealm invalid) | | bar.foo.example | *ar.foo.example | NO (NAIRealm invalid) |
| bar.foo.example | bar.*.example | NO (NAIRealm invalid) | | bar.foo.example | bar.*.example | NO (NAIRealm invalid) |
| bar.foo.example | *.*.example | NO (NAIRealm invalid) | | bar.foo.example | *.*.example | NO (NAIRealm invalid) |
| sub.bar.foo.example | *.*.example | NO (NAIRealm invalid) | | sub.bar.foo.example | *.*.example | NO (NAIRealm invalid) |
| sub.bar.foo.example | *.bar.foo.example | YES | | sub.bar.foo.example | *.bar.foo.example | YES |
+-----------------+-----------------------------------------------+ +-----------------+-----------------------------------------------+
Figure 6: Examples for NAI realm vs. certificate matching Figure 6: Examples for NAI Realm vs. Certificate Matching
Appendix A contains the ASN.1 definition of the above objects. Appendix A contains the ASN.1 definition of the above objects.
3. DNS-based NAPTR/SRV Peer Discovery 3. DNS-Based NAPTR/SRV Peer Discovery
3.1. Applicability 3.1. Applicability
Dynamic server discovery as defined in this document is only Dynamic server discovery as defined in this document is only
applicable for new AAA transactions and per service (i.e. distinct applicable for new AAA transactions and per service (i.e., distinct
discovery is needed for Authentication, Accounting, and Dynamic discovery is needed for Authentication, Accounting, and Dynamic
Authorization) where a RADIUS entity which acts as a forwarding Authorization) where a RADIUS entity that acts as a forwarding server
server for one or more realms receives a request with a realm for for one or more realms receives a request with a realm for which it
which it is not authoritative, and which no explicit next hop is is not authoritative, and which no explicit next hop is configured.
configured. It is only applicable for It is only applicable for
a. new user sessions, i.e. for the initial Access-Request. a. new user sessions, i.e., for the initial Access-Request.
Subsequent messages concerning this session, for example Access- Subsequent messages concerning this session, for example, Access-
Challenges and Access-Accepts use the previously-established Challenges and Access-Accepts, use the previously established
communication channel between client and server. communication channel between client and server.
b. the first accounting ticket for a user session. b. the first accounting ticket for a user session.
c. the first RADIUS DynAuth packet for a user session. c. the first RADIUS DynAuth packet for a user session.
3.2. Configuration Variables 3.2. Configuration Variables
The algorithm contains various variables for timeouts. These The algorithm contains various variables for timeouts. These
variables are named here and reasonable default values are provided. variables are named here and reasonable default values are provided.
Implementations wishing to deviate from these defaults should make Implementations wishing to deviate from these defaults should make
they understand the implications of changes. sure they understand the implications of changes.
DNS_TIMEOUT: maximum amount of time to wait for the complete set DNS_TIMEOUT: maximum amount of time to wait for the complete set
of all DNS queries to complete: Default = 3 seconds of all DNS queries to complete: Default = 3 seconds
MIN_EFF_TTL: minimum DNS TTL of discovered targets: Default = 60 MIN_EFF_TTL: minimum DNS TTL of discovered targets: Default = 60
seconds seconds
BACKOFF_TIME: if no conclusive DNS response was retrieved after BACKOFF_TIME: if no conclusive DNS response was retrieved after
DNS_TIMEOUT, do not attempt dynamic discovery before BACKOFF_TIME DNS_TIMEOUT, do not attempt dynamic discovery before BACKOFF_TIME
has elapsed. Default = 600 seconds has elapsed: Default = 600 seconds
3.3. Terms 3.3. Terms
Positive DNS response: a response which contains the RR that was Positive DNS response: A response that contains the RR that was
queried for. queried for.
Negative DNS response: a response which does not contain the RR that Negative DNS response: A response that does not contain the RR that
was queried for, but contains an SOA record along with a TTL was queried for but contains an SOA record along with a TTL
indicating cache duration for this negative result. indicating cache duration for this negative result.
DNS Error: Where the algorithm states "name resolution returns with DNS Error: Where the algorithm states "name resolution returns with
an error", this shall mean that either the DNS request timed out, or an error", this shall mean that either the DNS request timed out or
a DNS response which is neither a positive nor a negative response it is a DNS response, which is neither a positive nor a negative
(e.g. SERVFAIL). response (e.g., SERVFAIL).
Effective TTL: The validity period for discovered RADIUS/TLS target Effective TTL: The validity period for discovered RADIUS/TLS target
hosts. Calculated as: Effective TTL (set of DNS TTL values) = max { hosts. Calculated as: Effective TTL (set of DNS TTL values) = max {
MIN_EFF_TTL, min { DNS TTL values } } MIN_EFF_TTL, min { DNS TTL values } }
SRV lookup: for the purpose of this specification, SRV lookup SRV lookup: For the purpose of this specification, SRV lookup
procedures are defined as per [RFC2782], but excluding that RFCs "A" procedures are defined as per [RFC2782] but excluding that RFCs "A"
fallback as defined in its section "Usage Rules", final "else" fallback as defined in the "Usage Rules" section, final "else"
clause. clause.
Greedy result evaluation: The NAPTR to SRV/A/AAAA resolution may lead Greedy result evaluation: The NAPTR to SRV/A/AAAA resolution may lead
to a tree of results, whose leafs are the IP addresses to contact. to a tree of results, whose leafs are the IP addresses to contact.
The branches of the tree are ordered according to their order/ The branches of the tree are ordered according to their order/
preference DNS properties. An implementation is executing greedy preference DNS properties. An implementation is executing greedy
result evaluation if it uses a depth-first search in the tree along result evaluation if it uses a depth-first search in the tree along
the highest order results, attempts to connect to the corresponding the highest order results, attempts to connect to the corresponding
resulting IP addresses, and only backtracks to other branches if the resulting IP addresses, and only backtracks to other branches if the
higher ordered results did not end in successful connection attempts. higher ordered results did not end in successful connection attempts.
3.4. Realm to RADIUS server resolution algorithm 3.4. Realm to RADIUS Server Resolution Algorithm
3.4.1. Input 3.4.1. Input
For RADIUS Authentication and RADIUS Accounting server discovery, For RADIUS Authentication and RADIUS Accounting server discovery,
input I to the algorithm is the RADIUS User-Name attribute with input I to the algorithm is the RADIUS User-Name attribute with
content of the form "user@realm"; the literal @ sign being the content of the form "user@realm"; the literal "@" sign is the
separator between a local user identifier within a realm and its separator between a local user identifier within a realm and its
realm. The use of multiple literal @ signs in a User-Name is realm. The use of multiple literal "@" signs in a User-Name is
strongly discouraged; but if present, the last @ sign is to be strongly discouraged; but if present, the last "@" sign is to be
considered the separator. All previous instances of the @ sign are considered the separator. All previous instances of the "@" sign are
to be considered part of the local user identifier. to be considered part of the local user identifier.
For RADIUS DynAuth Server discovery, input I to the algorithm is the For RADIUS DynAuth server discovery, input I to the algorithm is the
domain name of the operator of a RADIUS realm as was communicated domain name of the operator of a RADIUS realm as was communicated
during user authentication using the Operator-Name attribute during user authentication using the Operator-Name attribute
([RFC5580], section 4.1). Only Operator-Name values with the ([RFC5580], Section 4.1). Only Operator-Name values with the
namespace "1" are supported by this algorithm - the input to the namespace "1" are supported by this algorithm -- the input to the
algorithm is the actual domain name, preceeded with an "@" (but algorithm is the actual domain name, preceded with an "@" (but
without the "1" namespace identifier byte of that attribute). without the "1" namespace identifier byte of that attribute).
Note well: The attribute User-Name is defined to contain UTF-8 text. Note well: The attribute User-Name is defined to contain UTF-8 text.
In practice, the content may or may not be UTF-8. Even if UTF-8, it In practice, the content may or may not be UTF-8. Even if UTF-8, it
may or may not map to a domain name in the realm part. Implementors may or may not map to a domain name in the realm part. Implementors
MUST take possible conversion error paths into consideration when MUST take possible conversion error paths into consideration when
parsing incoming User-Name attributes. This document describes parsing incoming User-Name attributes. This document describes
server discovery only for well-formed realms mapping to DNS domain server discovery only for well-formed realms mapping to DNS domain
names in UTF-8 encoding. The result of all other possible contents names in UTF-8 encoding. The result of all other possible contents
of User-Name is unspecified; this includes, but is not limited to: of User-Name is unspecified; this includes, but is not limited to:
Usage of separators other than @. Usage of separators other than "@".
Encoding of User-Name in local encodings. Encoding of User-Name in local encodings.
UTF-8 realms which fail the conversion rules as per [RFC5891]. UTF-8 realms that fail the conversion rules as per [RFC5891].
UTF-8 realms which end with a . ("dot") character. UTF-8 realms that end with a "." ("dot") character.
For the last bullet point, "trailing dot", special precautions should For the last bullet point, "trailing dot", special precautions should
be taken to avoid problems when resolving servers with the algorithm be taken to avoid problems when resolving servers with the algorithm
below: they may resolve to a RADIUS server even if the peer RADIUS below: they may resolve to a RADIUS server even if the peer RADIUS
server only is configured to handle the realm without the trailing server only is configured to handle the realm without the trailing
dot. If that RADIUS server again uses NAI discovery to determine the dot. If that RADIUS server again uses NAI discovery to determine the
authoritative server, the server will forward the request to authoritative server, the server will forward the request to
localhost, resulting in a tight endless loop. localhost, resulting in a tight endless loop.
3.4.2. Output 3.4.2. Output
Output O of the algorithm is a two-tuple consisting of: O-1) a set of Output O of the algorithm is a two-tuple consisting of: O-1) a set of
tuples {hostname; port; protocol; order/preference; Effective TTL} - tuples {hostname; port; protocol; order/preference; Effective TTL} --
the set can be empty; and O-2) an integer: if the set in the first the set can be empty -- and O-2) an integer. If the set in the first
part of the tuple is empty, the integer contains the Effective TTL part of the tuple is empty, the integer contains the Effective TTL
for backoff timeout, if the set is not empty, the integer is set to 0 for backoff timeout; if the set is not empty, the integer is set to 0
(and not used). (and not used).
3.4.3. Algorithm 3.4.3. Algorithm
The algorithm to determine the RADIUS server to contact is as The algorithm to determine the RADIUS server to contact is as
follows: follows:
1. Determine P = (position of last "@" character) in I. 1. Determine P = (position of last "@" character) in I.
2. generate R = (substring from P+1 to end of I) 2. Generate R = (substring from P+1 to end of I).
3. modify R according to agreed consortium procedures if applicable 3. Modify R according to agreed consortium procedures if
applicable.
4. convert R to a representation usable by the name resolution 4. Convert R to a representation usable by the name resolution
library if needed library if needed.
5. Initialize TIMER = 0; start TIMER. If TIMER reaches 5. Initialize TIMER = 0; start TIMER. If TIMER reaches
DNS_TIMEOUT, continue at step 20. DNS_TIMEOUT, continue at step 20.
6. Using the host's name resolution library, perform a NAPTR query 6. Using the host's name resolution library, perform a NAPTR query
for R (see "Delay considerations" below). If the result is a for R (see "Delay Considerations", Section 3.4.5, below). If
negative DNS response, O-2 = Effective TTL ( TTL value of the the result is a negative DNS response, O-2 = Effective TTL ( TTL
SOA record ) and continue at step 13. If name resolution value of the SOA record ) and continue at step 13. If name
returns with error, O-1 = { empty set }, O-2 = BACKOFF_TIME and resolution returns with error, O-1 = { empty set }, O-2 =
terminate. BACKOFF_TIME, and terminate.
7. Extract NAPTR records with service tag "aaa+auth", "aaa+acct", 7. Extract NAPTR records with service tags "aaa+auth", "aaa+acct",
"aaa+dynauth" as appropriate. Keep note of the protocol tag and and "aaa+dynauth" as appropriate. Keep note of the protocol tag
remaining TTL of each of the discovered NAPTR records. and remaining TTL of each of the discovered NAPTR records.
8. If no records found, continue at step 13. 8. If no records are found, continue at step 13.
9. For the extracted NAPTRs, perform successive resolution as 9. For the extracted NAPTRs, perform successive resolution as
defined in [RFC3958], section 2.2. An implementation MAY use defined in [RFC3958], Section 2.2. An implementation MAY use
greedy result evaluation according to the NAPTR order/preference greedy result evaluation according to the NAPTR order/preference
fields (i.e. can execute the subsequent steps of this algorithm fields (i.e., can execute the subsequent steps of this algorithm
for the highest-order entry in the set of results, and only for the highest-order entry in the set of results and only look
lookup the remainder of the set if necessary). up the remainder of the set if necessary).
10. If the set of hostnames is empty, O-1 = { empty set }, O-2 = 10. If the set of hostnames is empty, O-1 = { empty set }, O-2 =
BACKOFF_TIME and terminate. BACKOFF_TIME, and terminate.
11. O' = (set of {hostname; port; protocol; order/preference; 11. O' = (set of {hostname; port; protocol; order/preference;
Effective TTL ( all DNS TTLs that led to this hostname ) } for Effective TTL ( all DNS TTLs that led to this hostname ) } for
all terminal lookup results). all terminal lookup results).
12. Proceed with step 18. 12. Proceed with step 18.
13. Generate R' = (prefix R with "_radiustls._tcp." and/or 13. Generate R' = (prefix R with "_radiustls._tcp." and/or
"_radiustls._udp.") "_radiustls._udp.").
14. Using the host's name resolution library, perform SRV lookup 14. Using the host's name resolution library, perform SRV lookup
with R' as label (see "Delay considerations" below). with R' as label (see "Delay Considerations", Section 3.4.5,
below).
15. If name resolution returns with error, O-1 = { empty set }, O-2 15. If name resolution returns with error, O-1 = { empty set }, O-2
= BACKOFF_TIME and terminate. = BACKOFF_TIME, and terminate.
16. If the result is a negative DNS response, O-1 = { empty set }, 16. If the result is a negative DNS response, O-1 = { empty set },
O-2 = min { O-2, Effective TTL ( TTL value of the SOA record ) } O-2 = min { O-2, Effective TTL ( TTL value of the SOA record )
and terminate. }, and terminate.
17. O' = (set of {hostname; port; protocol; order/preference; 17. O' = (set of {hostname; port; protocol; order/preference;
Effective TTL ( all DNS TTLs that led to this result ) } for all Effective TTL ( all DNS TTLs that led to this result ) } for all
hostnames). hostnames).
18. Generate O-1 by resolving hostnames in O' into corresponding A 18. Generate O-1 by resolving hostnames in O' into corresponding A
and/or AAAA addresses: O-1 = (set of {IP address; port; and/or AAAA addresses: O-1 = (set of {IP address; port;
protocol; order/preference; Effective TTL ( all DNS TTLs that protocol; order/preference; Effective TTL ( all DNS TTLs that
led to this result ) } for all hostnames ), O-2 = 0. led to this result ) } for all hostnames ), O-2 = 0.
19. For each element in O-1, test if the original request which 19. For each element in O-1, test if the original request that
triggered dynamic discovery was received on {IP address; port}. triggered dynamic discovery was received on {IP address; port}.
If yes, O-1 = { empty set }, O-2 = BACKOFF_TIME, log error, If yes, O-1 = { empty set }, O-2 = BACKOFF_TIME, log error, and
Terminate (see next section for a rationale). If no, O is the terminate (see next section for a rationale). If no, O is the
result of dynamic discovery. Terminate. result of dynamic discovery; terminate.
20. O-1 = { empty set }, O-2 = BACKOFF_TIME, log error, Terminate. 20. O-1 = { empty set }, O-2 = BACKOFF_TIME, log error, and
terminate.
3.4.4. Validity of results 3.4.4. Validity of Results
The dynamic discovery algorithm is used by servers which do not have The discovery algorithm is used by servers that do not have
sufficient configuration information to process an incoming request sufficient configuration information to process an incoming request
on their own. If the discovery algorithm result contains the on their own. If the discovery algorithm result contains the
server's own listening address (IP address and port), then there is a server's own listening address (IP address and port), then there is a
potential for an endless forwarding loop. If the listening address potential for an endless forwarding loop. If the listening address
is the DNS result with the highest priorty, the server will enter a is the DNS result with the highest priority, the server will enter a
tight loop (the server would forward the request to itself, tight loop (the server would forward the request to itself,
triggering dynamic discovery again in a perpetual loop). If the triggering dynamic discovery again in a perpetual loop). If the
address has a lower priority in the set of results, there is a address has a lower priority in the set of results, there is a
potential loop with intermediate hops in between (the server could potential loop with intermediate hops in between (the server could
forward to another host with a higher priority, which might use DNS forward to another host with a higher priority, which might use DNS
itself and forward the packet back to the first server). The itself and forward the packet back to the first server). The
underlying reason that enables these loops is that the server underlying reason that enables these loops is that the server
executing the discovery algorithm is seriously misconfigured in that executing the discovery algorithm is seriously misconfigured in that
it does not recognise the request as one that is to be processed by it does not recognize the request as one that is to be processed by
itself. RADIUS has no built-in loop detection, so any such loops itself. RADIUS has no built-in loop detection, so any such loops
would remain undetected. So, if step 18 of the algorithm discovers would remain undetected. So, if step 18 of the algorithm discovers
such a possible-loop situation, the algorithm should be aborted and such a possible-loop situation, the algorithm should be aborted and
an error logged. Note that this safeguard does not provide perfect an error logged. Note that this safeguard does not provide perfect
protection against routing loops. One reason which might introduce a protection against routing loops. One reason that might introduce a
loop include the possiblity that a subsequent hop has a statically loop includes the possibility that a subsequent hop has a statically
configured next-hop which leads to an earlier host in the loop. configured next hop that leads to an earlier host in the loop.
Another reason for occuring loops is if the algorithm was executed Another reason for occurring loops is if the algorithm was executed
with greedy result evaluation, and the own address was in a lower- with greedy result evaluation, and the server's own address was in a
priority branch of the result set which was not retrieved from DNS at lower-priority branch of the result set that was not retrieved from
all, and thus can't be detected. DNS at all, and thus can't be detected.
After executing the above algorithm, the RADIUS server establishes a After executing the above algorithm, the RADIUS server establishes a
connection to a home server from the result set. This connection can connection to a home server from the result set. This connection can
potentially remain open for an indefinite amount of time. This potentially remain open for an indefinite amount of time. This
conflicts with the possibility of changing device and network conflicts with the possibility of changing device and network
configurations on the receiving end. Typically, TTL values for configurations on the receiving end. Typically, TTL values for
records in the name resolution system are used to indicate how long records in the name resolution system are used to indicate how long
it is safe to rely on the results of the name resolution. If these it is safe to rely on the results of the name resolution. If these
TTLs are very low, thrashing of connections becomes possible; the TTLs are very low, thrashing of connections becomes possible; the
Effective TTL mitigates that risk. When a connection is open and the Effective TTL mitigates that risk. When a connection is open and the
smallest of the Effective TTL value which was learned during smallest of the Effective TTL value that was learned during
discovering the server has not expired, subsequent new user sessions discovering the server has not expired, subsequent new user sessions
for the realm which corresponds to that open connection SHOULD re-use for the realm that corresponds to that open connection SHOULD reuse
the existing connection and SHOULD NOT re-execute the dynamic the existing connection and SHOULD NOT re-execute the discovery
discovery algorithm nor open a new connection. To allow for a change algorithm nor open a new connection. To allow for a change of
of configuration, a RADIUS server SHOULD re-execute the dynamic configuration, a RADIUS server SHOULD re-execute the discovery
discovery algorithm after the Effective TTL that is associated with algorithm after the Effective TTL that is associated with this
this connection has expired. The server SHOULD keep the session open connection has expired. The server SHOULD keep the session open
during this re-assessment to avoid closure and immediate re-opening during this reassessment to avoid closure and immediate reopening of
of the connection should the result not have changed. the connection should the result not have changed.
Should the algorithm above terminate with O-1 = empty set, the RADIUS Should the algorithm above terminate with O-1 = { empty set }, the
server SHOULD NOT attempt another execution of this algorithm for the RADIUS server SHOULD NOT attempt another execution of this algorithm
same target realm before the timeout O-2 has passed. for the same target realm before the timeout O-2 has passed.
3.4.5. Delay considerations 3.4.5. Delay Considerations
The host's name resolution library may need to contact outside The host's name resolution library may need to contact outside
entities to perform the name resolution (e.g. authoritative name entities to perform the name resolution (e.g., authoritative name
servers for a domain), and since the NAI discovery algorithm is based servers for a domain), and since the NAI discovery algorithm is based
on uncontrollable user input, the destination of the lookups is out on uncontrollable user input, the destination of the lookups is out
of control of the server that performs NAI discovery. If such of control of the server that performs NAI discovery. If such
outside entities are misconfigured or unreachable, the algorithm outside entities are misconfigured or unreachable, the algorithm
above may need an unacceptably long time to terminate. Many RADIUS above may need an unacceptably long time to terminate. Many RADIUS
implementations time out after five seconds of delay between Request implementations time out after five seconds of delay between Request
and Response. It is not useful to wait until the host name and Response. It is not useful to wait until the host name
resolution library signals a timeout of its name resolution resolution library signals a timeout of its name resolution
algorithms. The algorithm therefore controls execution time with algorithms. The algorithm therefore controls execution time with
TIMER. Execution of the NAI discovery algorithm SHOULD be non- TIMER. Execution of the NAI discovery algorithm SHOULD be non-
blocking (i.e. allow other requests to be processed in parallel to blocking (i.e., allow other requests to be processed in parallel to
the execution of the algorithm). the execution of the algorithm).
3.4.6. Example 3.4.6. Example
Assume Assume
a user from the Technical University of Munich, Germany, has a a user from the Technical University of Munich, Germany, has a
RADIUS User-Name of "foobar@tu-m[U+00FC]nchen.example". RADIUS User-Name of "foobar@tu-m[U+00FC]nchen.example".
The name resolution library on the RADIUS forwarding server does The name resolution library on the RADIUS forwarding server does
not have the realm tu-m[U+00FC]nchen.example in its forwarding not have the realm tu-m[U+00FC]nchen.example in its forwarding
configuration, but uses DNS for name resolution and has configured configuration but uses DNS for name resolution and has configured
the use of Dynamic Discovery to discover RADIUS servers. the use of dynamic discovery to discover RADIUS servers.
It is IPv6-enabled and prefers AAAA records over A records. It is IPv6 enabled and prefers AAAA records over A records.
It is listening for incoming RADIUS/TLS requests on 192.0.2.1, TCP It is listening for incoming RADIUS/TLS requests on 192.0.2.1,
/2083. TCP/2083.
May the configuration variables be May the configuration variables be
DNS_TIMEOUT = 3 seconds DNS_TIMEOUT = 3 seconds
MIN_EFF_TTL = 60 seconds MIN_EFF_TTL = 60 seconds
BACKOFF_TIME = 3600 seconds BACKOFF_TIME = 3600 seconds
If DNS contains the following records: If DNS contains the following records
xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s" xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s"
"aaa+auth:radius.tls.tcp" "" _myradius._tcp.xn--tu-mnchen- "aaa+auth:radius.tls.tcp" "" _myradius._tcp.xn--tu-mnchen-
t9a.example. t9a.example.
xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s" xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s"
"fooservice:bar.dccp" "" _abc123._def.xn--tu-mnchen-t9a.example. "fooservice:bar.dccp" "" _abc123._def.xn--tu-mnchen-t9a.example.
_myradius._tcp.xn--tu-mnchen-t9a.example. IN SRV 0 10 2083 _myradius._tcp.xn--tu-mnchen-t9a.example. IN SRV 0 10 2083
radsecserver.xn--tu-mnchen-t9a.example. radsecserver.xn--tu-mnchen-t9a.example.
skipping to change at page 22, line 25 skipping to change at page 22, line 50
Then the algorithm executes as follows, with I = Then the algorithm executes as follows, with I =
"foobar@tu-m[U+00FC]nchen.example", and no consortium name mangling "foobar@tu-m[U+00FC]nchen.example", and no consortium name mangling
in use: in use:
1. P = 7 1. P = 7
2. R = "tu-m[U+00FC]nchen.example" 2. R = "tu-m[U+00FC]nchen.example"
3. NOOP 3. NOOP
4. name resolution library converts R to xn--tu-mnchen-t9a.example 4. Name resolution library converts R to xn--tu-mnchen-t9a.example
5. TIMER starts. 5. TIMER starts.
6. Result: 6. Result:
(TTL = 47) 50 50 "s" "aaa+auth:radius.tls.tcp" "" (TTL = 47) 50 50 "s" "aaa+auth:radius.tls.tcp" ""
_myradius._tcp.xn--tu-mnchen-t9a.example. _myradius._tcp.xn--tu-mnchen-t9a.example.
(TTL = 522) 50 50 "s" "fooservice:bar.dccp" "" (TTL = 522) 50 50 "s" "fooservice:bar.dccp" ""
_abc123._def.xn--tu-mnchen-t9a.example. _abc123._def.xn--tu-mnchen-t9a.example.
skipping to change at page 23, line 4 skipping to change at page 23, line 28
8. NOOP 8. NOOP
9. Successive resolution performs SRV query for label 9. Successive resolution performs SRV query for label
_myradius._tcp.xn--tu-mnchen-t9a.example, which results in _myradius._tcp.xn--tu-mnchen-t9a.example, which results in
(TTL 499) 0 10 2083 radsec.xn--tu-mnchen-t9a.example. (TTL 499) 0 10 2083 radsec.xn--tu-mnchen-t9a.example.
(TTL 2200) 0 20 2083 backup.xn--tu-mnchen-t9a.example. (TTL 2200) 0 20 2083 backup.xn--tu-mnchen-t9a.example.
10. NOOP 10. NOOP
11. O' = { 11. O' = {
(radsec.xn--tu-mnchen-t9a.example.; 2083; RADIUS/TLS; 10; (radsec.xn--tu-mnchen-t9a.example.; 2083; RADIUS/TLS; 10;
60), 60),
(backup.xn--tu-mnchen-t9a.example.; 2083; RADIUS/TLS; 20; 60) (backup.xn--tu-mnchen-t9a.example.; 2083; RADIUS/TLS; 20; 60)
} // minimum TTL is 47, up'ed to MIN_EFF_TTL } // minimum TTL is 47, upped to MIN_EFF_TTL
12. Continuing at 18. 12. Continuing at 18.
13. (not executed) 13. (not executed)
14. (not executed) 14. (not executed)
15. (not executed) 15. (not executed)
16. (not executed) 16. (not executed)
skipping to change at page 23, line 43 skipping to change at page 24, line 22
19. No match with own listening address; terminate with tuple (O-1, 19. No match with own listening address; terminate with tuple (O-1,
O-2) from previous step. O-2) from previous step.
The implementation will then attempt to connect to two servers, with The implementation will then attempt to connect to two servers, with
preference to [2001:0DB8::202:44ff:fe0a:f704]:2083 using the RADIUS/ preference to [2001:0DB8::202:44ff:fe0a:f704]:2083 using the RADIUS/
TLS protocol. TLS protocol.
4. Operations and Manageability Considerations 4. Operations and Manageability Considerations
The discovery algorithm as defined in this document contains several The discovery algorithm as defined in this document contains several
options; the major ones being use of NAPTR vs. SRV; how to determine options: the major ones are use of NAPTR vs. SRV; how to determine
the authorization status of a contacted server for a given realm; the authorization status of a contacted server for a given realm; and
which trust anchors to consider trustworthy for the RADIUS which trust anchors to consider trustworthy for the RADIUS
conversation setup. conversation setup.
Random parties which do not agree on the same set of options may not Random parties that do not agree on the same set of options may not
be able to interoperate. However, such a global interoperability is be able to interoperate. However, such a global interoperability is
not intended by this document. not intended by this document.
Discovery as per this document becomes important inside a roaming Discovery as per this document becomes important inside a roaming
consortium, which has set up roaming agreements with the other consortium, which has set up roaming agreements with the other
partners. Such roaming agreements require much more than a technical partners. Such roaming agreements require much more than a technical
means of server discovery; there are administrative and contractual means of server discovery; there are administrative and contractual
considerations at play (service contracts, backoffice compensations, considerations at play (service contracts, back-office compensations,
procedures, ...). procedures, etc.).
A roaming consortium's roaming agreement must include a profile of A roaming consortium's roaming agreement must include a profile of
which choice points of this document to use. So long as the roaming which choice points in this document to use. So as long as the
consortium can settle on one deployment profile, they will be able to roaming consortium can settle on one deployment profile, they will be
interoperate based on that choice; this per-consortium able to interoperate based on that choice; this per-consortium
interoperability is the intended scope of this document. interoperability is the intended scope of this document.
5. Security Considerations 5. Security Considerations
When using DNS without DNSSEC security extensions and validation for When using DNS without DNSSEC security extensions and validation for
all of the replies to NAPTR, SRV and A/AAAA requests as described in all of the replies to NAPTR, SRV, and A/AAAA requests as described in
section Section 3, the result of the discovery process can not be Section 3, the result of the discovery process can not be trusted.
trusted. Even if it can be trusted (i.e. DNSSEC is in use), actual Even if it can be trusted (i.e., DNSSEC is in use), actual
authorization of the discovered server to provide service for the authorization of the discovered server to provide service for the
given realm needs to be verified. A mechanism from section given realm needs to be verified. A mechanism from Section 2.1.1.3
Section 2.1.1.3 or equivalent MUST be used to verify authorization. or equivalent MUST be used to verify authorization.
The algorithm has a configurable completion timeout DNS_TIMEOUT The algorithm has a configurable completion timeout DNS_TIMEOUT
defaulting to three seconds for RADIUS' operational reasons. The defaulting to three seconds for RADIUS' operational reasons. The
lookup of DNS resource records based on unverified user input is an lookup of DNS resource records based on unverified user input is an
attack vector for DoS attacks: an attacker might intentionally craft attack vector for DoS attacks: an attacker might intentionally craft
bogus DNS zones which take a very long time to reply (e.g. due to a bogus DNS zones that take a very long time to reply (e.g., due to a
particularly byzantine tree structure, or artificial delays in particularly byzantine tree structure or artificial delays in
responses). responses).
To mitigate this DoS vector, implementations SHOULD consider rate- To mitigate this DoS vector, implementations SHOULD consider rate
limiting either their amount of new executions of the dynamic limiting either the amount of new executions of the discovery
discovery algorithm as a whole, or the amount of intermediate algorithm as a whole or the amount of intermediate responses to
responses to track, or at least the number of pending DNS queries. track, or at least the number of pending DNS queries.
Implementations MAY choose lower values than the default for Implementations MAY choose lower values than the default for
DNS_TIMEOUT to limit the impact of DoS attacks via that vector. They DNS_TIMEOUT to limit the impact of DoS attacks via that vector. They
MAY also continue their attempt to resolve DNS records even after MAY also continue their attempt to resolve DNS records even after
DNS_TIMEOUT has passed; a subsequent request for the same realm might DNS_TIMEOUT has passed; a subsequent request for the same realm might
benefit from retrieving the results anyway. The amount of time to benefit from retrieving the results anyway. The amount of time spent
spent waiting for a result will influence the impact of a possible waiting for a result will influence the impact of a possible DoS
DoS attack; the waiting time value is implementation dependent and attack; the waiting time value is implementation dependent and
outside the scope of this specification. outside the scope of this specification.
With Dynamic Discovery being enabled for a RADIUS Server, and With dynamic discovery being enabled for a RADIUS server, and
depending on the deployment scenario, the server may need to open up depending on the deployment scenario, the server may need to open up
its target IP address and port for the entire internet, because its target IP address and port for the entire Internet because
arbitrary clients may discover it as a target for their arbitrary clients may discover it as a target for their
authentication requests. If such clients are not part of the roaming authentication requests. If such clients are not part of the roaming
consortium, the RADIUS/TLS connection setup phase will fail (which is consortium, the RADIUS/TLS connection setup phase will fail (which is
intended) but the computational cost for the connection attempt is intended), but the computational cost for the connection attempt is
significant. With the port for a TLS-based service open, the RADIUS significant. When the port for a TLS-based service is open, the
server shares all the typical attack vectors for services based on RADIUS server shares all the typical attack vectors for services
TLS (such as HTTPS, SMTPS, ...). Deployments of RADIUS/TLS with based on TLS (such as HTTPS and SMTPS). Deployments of RADIUS/TLS
Dynamic Discovery should consider these attack vectors and take with dynamic discovery should consider these attack vectors and take
appropriate counter-measures (e.g. blacklisting known-bad IPs on a appropriate countermeasures (e.g., blacklisting known bad IPs on a
firewall, rate-limiting new connection attempts, etc.). firewall, rate limiting new connection attempts, etc.).
6. Privacy Considerations 6. Privacy Considerations
The classic RADIUS operational model (known, pre-configured peers, The classic RADIUS operational model (known, preconfigured peers,
shared secret security, mostly plaintext communication) and this new shared secret security, and mostly plaintext communication) and this
RADIUS dynamic discovery model (peer discovery with DNS, PKI security new RADIUS dynamic discovery model (peer discovery with DNS, PKI
and packet confidentiality) differ significantly in their impact on security, and packet confidentiality) differ significantly in their
the privacy of end users trying to authenticate to a RADIUS server. impact on the privacy of end users trying to authenticate to a RADIUS
server.
With classic RADIUS, traffic in large environments gets aggregated by With classic RADIUS, traffic in large environments gets aggregated by
statically configured clearinghouses. The packets sent to those statically configured clearinghouses. The packets sent to those
clearinghouses and their responses are mostly unprotected. As a clearinghouses and their responses are mostly unprotected. As a
consequence, consequence,
o All intermediate IP hops can inspect most of the packet payload in o All intermediate IP hops can inspect most of the packet payload in
clear text, including the User-Name and Calling-Station-Id clear text, including the User-Name and Calling-Station-Id
attributes, and can observe which client sent the packet to which attributes, and can observe which client sent the packet to which
clearinghouse. This allows the creation of mobility profiles for clearinghouse. This allows the creation of mobility profiles for
any passive observer on the IP path. any passive observer on the IP path.
o The existence of a central clearinghouse creates an opportunity o The existence of a central clearinghouse creates an opportunity
for the clearinghouse to trivially create the same mobility for the clearinghouse to trivially create the same mobility
profiles. The clearinghouse may or may not be trusted not to do profiles. The clearinghouse may or may not be trusted not to do
this, e.g. by sufficiently threatening contractual obligations. this, e.g., by sufficiently threatening contractual obligations.
o In addition to that, with the clearinghouse being a RADIUS o In addition to that, with the clearinghouse being a RADIUS
intermediate in possession of a valid shared secret, the intermediate in possession of a valid shared secret, the
clearinghouse can observe and record even the security-critical clearinghouse can observe and record even the security-critical
RADIUS attributes such as User-Password. This risk may be RADIUS attributes such as User-Password. This risk may be
mitigated by choosing authentication payloads which are mitigated by choosing authentication payloads that are
cryptographically secured and do not use the attribute User- cryptographically secured and do not use the attribute User-
Password - such as certain EAP types. Password -- such as certain EAP types.
o There is no additional information disclosure to parties outside o There is no additional information disclosure to parties outside
the IP path between the RADIUS client and server (in particular, the IP path between the RADIUS client and server (in particular,
no DNS servers learn about realms of current ongoing no DNS servers learn about realms of current ongoing
authentications). authentications).
With RADIUS and dynamic discovery, With RADIUS and dynamic discovery,
o This protocol allows for RADIUS clients to identify and directly o This protocol allows for RADIUS clients to identify and directly
connect to the RADIUS home server. This can eliminate the use of connect to the RADIUS home server. This can eliminate the use of
clearinghouses to do forwarding of requests, and it also clearinghouses to do forwarding of requests, and it also
eliminates the ability of the clearinghouse to then aggregate the eliminates the ability of the clearinghouse to then aggregate the
user information that flows through it. However, there exist user information that flows through it. However, there are
reasons why clearinghouses might still be used. One reason to reasons why clearinghouses might still be used. One reason to
keep a clearinghouse is to act as a gateway for multiple backends keep a clearinghouse is to act as a gateway for multiple backends
in a company; another reason may be a requirement to sanitise in a company; another reason may be a requirement to sanitize
RADIUS datagrams (filter attributes, tag requests with new RADIUS datagrams (filter attributes, tag requests with new
attributes, ... ). attributes, etc.).
o Even where intermediate proxies continue to be used for reasons o Even where intermediate proxies continue to be used for reasons
unrelated to dynamic discovery, the number of such intermediates unrelated to dynamic discovery, the number of such intermediates
may be reduced by removing those proxies which are only deployed may be reduced by removing those proxies that are only deployed
for pure request routing reasons. This reduces the number of for pure request routing reasons. This reduces the number of
entities which can inspect the RADIUS traffic. entities that can inspect the RADIUS traffic.
o RADIUS clients which make use of dynamic discovery will need to o RADIUS clients that make use of dynamic discovery will need to
query the Domain Name System, and use a user's realm name as the query the Domain Name System and use a user's realm name as the
query label. A passive observer on the IP path between the RADIUS query label. A passive observer on the IP path between the RADIUS
client and the DNS server(s) being queried can learn that a user client and the DNS server(s) being queried can learn that a user
of that specific realm was trying to authenticate at that RADIUS of that specific realm was trying to authenticate at that RADIUS
client at a certain point in time. This may or may not be client at a certain point in time. This may or may not be
sufficient for the passive observer to create a mobility profile. sufficient for the passive observer to create a mobility profile.
During the recursive DNS resolution, a fair number of DNS servers During the recursive DNS resolution, a fair number of DNS servers
and the IP hops in between those get to learn that information. and the IP hops in between those get to learn that information.
Not every single authentication triggers DNS lookups, so there is Not every single authentication triggers DNS lookups, so there is
no one-to-one relation of leaked realm information and the number no one-to-one relation of leaked realm information and the number
of authentications for that realm. of authentications for that realm.
o Since dynamic discovery operates on a RADIUS hop-by-hop basis, o Since dynamic discovery operates on a RADIUS hop-by-hop basis,
there is no guarantee that the RADIUS payload is not transmitted there is no guarantee that the RADIUS payload is not transmitted
between RADIUS systems which do not make use of this algorithm, between RADIUS systems that do not make use of this algorithm, and
and possibly using other transports such as RADIUS/UDP. On such they possibly use other transports such as RADIUS/UDP. On such
hops, the enhanced privacy is jeopardized. hops, the enhanced privacy is jeopardized.
In summary, with classic RADIUS, few intermediate entities learn very In summary, with classic RADIUS, few intermediate entities learn very
detailed data about every ongoing authentications, while with dynamic detailed data about every ongoing authentication, while with dynamic
discovery, many entities learn only very little about recently discovery, many entities learn only very little about recently
authenticated realms. authenticated realms.
7. IANA Considerations 7. IANA Considerations
This document requests IANA registration of the following entries in Per this document, IANA has added the following entries in existing
existing registries: registries:
o S-NAPTR Application Service Tags registry o S-NAPTR Application Service Tags registry
* aaa+auth * aaa+auth
* aaa+acct * aaa+acct
* aaa+dynauth * aaa+dynauth
o S-NAPTR Application Protocol Tags registry o S-NAPTR Application Protocol Tags registry
* radius.tls.tcp * radius.tls.tcp
skipping to change at page 27, line 17 skipping to change at page 28, line 12
* aaa+dynauth * aaa+dynauth
o S-NAPTR Application Protocol Tags registry o S-NAPTR Application Protocol Tags registry
* radius.tls.tcp * radius.tls.tcp
* radius.dtls.udp * radius.dtls.udp
This document reserves the use of the "radiustls" and "radiusdtls" This document reserves the use of the "radiustls" and "radiusdtls"
service names. Registration information as per [RFC6335] section service names. Registration information as per Section 8.1.1 of
8.1.1 is as follows: [RFC6335] is as follows:
Service Name: radiustls; radiusdtls Service Name: radiustls; radiusdtls
Transport Protocols: TCP (for radiustls), UDP (for radiusdtls) Transport Protocols: TCP (for radiustls), UDP (for radiusdtls)
Assignee: IESG <iesg@ietf.org> Assignee: IESG <iesg@ietf.org>
Contact: IETF Chair <chair@ietf.org> Contact: IETF Chair <chair@ietf.org>
Description: Authentication, Accounting and Dynamic authorization Description: Authentication, Accounting, and Dynamic Authorization
via the RADIUS protocol. These service names are used to via the RADIUS protocol. These service names are used to
construct the SRV service labels "_radiustls" and "_radiusdtls" construct the SRV service labels "_radiustls" and "_radiusdtls"
for discovery of RADIUS/TLS and RADIUS/DTLS servers, respectively. for discovery of RADIUS/TLS and RADIUS/DTLS servers, respectively.
Reference: RFC Editor Note: please insert the RFC number of this Reference: RFC 7585
document. The protocol does not use broadcast, multicast or
anycast communication.
This specification makes use of the SRV Protocol identifiers "_tcp" This specification makes use of the SRV protocol identifiers "_tcp"
and "_udp" which are mentioned as early as [RFC2782] but do not and "_udp", which are mentioned as early as [RFC2782] but do not
appear to be assigned in an actual registry. Since they are in wide- appear to be assigned in an actual registry. Since they are in
spread use in other protocols, this specification refrains from widespread use in other protocols, this specification refrains from
requesting a new registry "RADIUS/TLS SRV Protocol Registry" and requesting a new registry "RADIUS/TLS SRV Protocol Registry" and
continues to make use of these tags implicitly. continues to make use of these tags implicitly.
This document requires that a number of Object Identifiers be Per this document, a number of Object Identifiers have been assigned.
assigned. They are now under the control of IANA following [RFC7299] They are now under the control of IANA following [RFC7299].
IANA is requested to assign the following identifiers:
TBD99 is to be assigned from the "SMI Security for PKIX Module IANA has assigned the following identifiers:
Identifier Registry". The suggested description is id-mod-nai-
realm-08.
TBD98 is to be assigned from the "SMI Security for PKIX Other Name 85 has been assigned from the "SMI Security for PKIX Module
Forms Registry." The suggested description is id-on-naiRealm. Identifier" registry. The description is id-mod-nai-realm-08.
RFC Editor Note: please replace the occurences of TBD98 and TBD99 in 8 has been assigned from the "SMI Security for PKIX Other Name
Appendix A of the document with the actually assigned numbers. Forms" registry. The description is id-on-naiRealm.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782, specifying the location of services (DNS SRV)", RFC 2782,
February 2000. DOI 10.17487/RFC2782, February 2000,
<http://www.rfc-editor.org/info/rfc2782>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)", RFC "Remote Authentication Dial In User Service (RADIUS)",
2865, June 2000. RFC 2865, DOI 10.17487/RFC2865, June 2000,
<http://www.rfc-editor.org/info/rfc2865>.
[RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000. [RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866,
DOI 10.17487/RFC2866, June 2000,
<http://www.rfc-editor.org/info/rfc2866>.
[RFC3958] Daigle, L. and A. Newton, "Domain-Based Application [RFC3958] Daigle, L. and A. Newton, "Domain-Based Application
Service Location Using SRV RRs and the Dynamic Delegation Service Location Using SRV RRs and the Dynamic Delegation
Discovery Service (DDDS)", RFC 3958, January 2005. Discovery Service (DDDS)", RFC 3958, DOI 10.17487/RFC3958,
January 2005, <http://www.rfc-editor.org/info/rfc3958>.
[RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. [RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B.
Aboba, "Dynamic Authorization Extensions to Remote Aboba, "Dynamic Authorization Extensions to Remote
Authentication Dial In User Service (RADIUS)", RFC 5176, Authentication Dial In User Service (RADIUS)", RFC 5176,
January 2008. DOI 10.17487/RFC5176, January 2008,
<http://www.rfc-editor.org/info/rfc5176>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008. (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<http://www.rfc-editor.org/info/rfc5280>.
[RFC5580] Tschofenig, H., Adrangi, F., Jones, M., Lior, A., and B. [RFC5580] Tschofenig, H., Ed., Adrangi, F., Jones, M., Lior, A., and
Aboba, "Carrying Location Objects in RADIUS and Diameter", B. Aboba, "Carrying Location Objects in RADIUS and
RFC 5580, August 2009. Diameter", RFC 5580, DOI 10.17487/RFC5580, August 2009,
<http://www.rfc-editor.org/info/rfc5580>.
[RFC5891] Klensin, J., "Internationalized Domain Names in [RFC5891] Klensin, J., "Internationalized Domain Names in
Applications (IDNA): Protocol", RFC 5891, August 2010. Applications (IDNA): Protocol", RFC 5891,
DOI 10.17487/RFC5891, August 2010,
<http://www.rfc-editor.org/info/rfc5891>.
[RFC6614] Winter, S., McCauley, M., Venaas, S., and K. Wierenga, [RFC6614] Winter, S., McCauley, M., Venaas, S., and K. Wierenga,
"Transport Layer Security (TLS) Encryption for RADIUS", "Transport Layer Security (TLS) Encryption for RADIUS",
RFC 6614, May 2012. RFC 6614, DOI 10.17487/RFC6614, May 2012,
<http://www.rfc-editor.org/info/rfc6614>.
[RFC7360] DeKok, A., "Datagram Transport Layer Security (DTLS) as a [RFC7360] DeKok, A., "Datagram Transport Layer Security (DTLS) as a
Transport Layer for RADIUS", RFC 7360, September 2014. Transport Layer for RADIUS", RFC 7360,
DOI 10.17487/RFC7360, September 2014,
<http://www.rfc-editor.org/info/rfc7360>.
[I-D.ietf-radext-nai] [RFC7542] DeKok, A., "The Network Access Identifier", RFC 7542,
DeKok, A., "The Network Access Identifier", draft-ietf- DOI 10.17487/RFC7542, May 2015,
radext-nai-15 (work in progress), December 2014. <http://www.rfc-editor.org/info/rfc7542>.
8.2. Informative References 8.2. Informative References
[RFC4017] Stanley, D., Walker, J., and B. Aboba, "Extensible [RFC4017] Stanley, D., Walker, J., and B. Aboba, "Extensible
Authentication Protocol (EAP) Method Requirements for Authentication Protocol (EAP) Method Requirements for
Wireless LANs", RFC 4017, March 2005. Wireless LANs", RFC 4017, DOI 10.17487/RFC4017, March
2005, <http://www.rfc-editor.org/info/rfc4017>.
[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. [RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA) Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165, RFC Transport Protocol Port Number Registry", BCP 165,
6335, August 2011. RFC 6335, DOI 10.17487/RFC6335, August 2011,
<http://www.rfc-editor.org/info/rfc6335>.
[RFC6733] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn, [RFC6733] Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
"Diameter Base Protocol", RFC 6733, October 2012. Ed., "Diameter Base Protocol", RFC 6733,
DOI 10.17487/RFC6733, October 2012,
<http://www.rfc-editor.org/info/rfc6733>.
[RFC7299] Housley, R., "Object Identifier Registry for the PKIX [RFC7299] Housley, R., "Object Identifier Registry for the PKIX
Working Group", RFC 7299, July 2014. Working Group", RFC 7299, DOI 10.17487/RFC7299, July 2014,
<http://www.rfc-editor.org/info/rfc7299>.
[I-D.wierenga-ietf-eduroam] [RFC7593] Wierenga, K., Winter, S., and T. Wolniewicz, "The eduroam
Wierenga, K., Winter, S., and T. Wolniewicz, "The eduroam Architecture for Network Roaming", RFC 7593,
architecture for network roaming", draft-wierenga-ietf- DOI 10.17487/RFC7593, September 2015,
eduroam-05 (work in progress), March 2015. <http://www.rfc-editor.org/info/rfc7593>.
Appendix A. ASN.1 Syntax of NAIRealm
Appendix A. Appendix A: ASN.1 Syntax of NAIRealm
PKIXNaiRealm08 {iso(1) identified-organization(3) dod(6) PKIXNaiRealm08 {iso(1) identified-organization(3) dod(6)
internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-nai-realm-08 (TBD99) } id-mod-nai-realm-08(85) }
DEFINITIONS EXPLICIT TAGS ::= DEFINITIONS EXPLICIT TAGS ::=
BEGIN BEGIN
-- EXPORTS ALL -- -- EXPORTS ALL --
IMPORTS IMPORTS
id-pkix id-pkix
FROM PKIX1Explicit-2009 FROM PKIX1Explicit-2009
{iso(1) identified-organization(3) dod(6) internet(1) {iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0) security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-pkix1-explicit-02(51)} id-mod-pkix1-explicit-02(51)}
-- from RFC 5280, RFC 5912 -- from RFCs 5280 and 5912
OTHER-NAME OTHER-NAME
FROM PKIX1Implicit-2009 FROM PKIX1Implicit-2009
{iso(1) identified-organization(3) dod(6) internet(1) security(5) {iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-implicit-02(59)} mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-implicit-02(59)}
-- from RFC 5280, RFC 5912 -- from RFCs 5280 and 5912
; ;
-- Service Name Object Identifier -- Service Name Object Identifier
id-on OBJECT IDENTIFIER ::= { id-pkix 8 } id-on OBJECT IDENTIFIER ::= { id-pkix 8 }
id-on-naiRealm OBJECT IDENTIFIER ::= { id-on TBD98 } id-on-naiRealm OBJECT IDENTIFIER ::= { id-on 8 }
-- Service Name -- Service Name
naiRealm OTHER-NAME ::= { NAIRealm IDENTIFIED BY { id-on-naiRealm }} naiRealm OTHER-NAME ::= { NAIRealm IDENTIFIED BY { id-on-naiRealm }}
ub-naiRealm-length INTEGER ::= 255 ub-naiRealm-length INTEGER ::= 255
NAIRealm ::= UTF8String (SIZE (1..ub-naiRealm-length)) NAIRealm ::= UTF8String (SIZE (1..ub-naiRealm-length))
END END
Authors' Addresses Authors' Addresses
Stefan Winter Stefan Winter
Fondation RESTENA Fondation RESTENA
6, rue Richard Coudenhove-Kalergi 6, rue Richard Coudenhove-Kalergi
Luxembourg 1359 Luxembourg 1359
LUXEMBOURG Luxembourg
Phone: +352 424409 1 Phone: +352 424409 1
Fax: +352 422473 Fax: +352 422473
EMail: stefan.winter@restena.lu Email: stefan.winter@restena.lu
URI: http://www.restena.lu. URI: http://www.restena.lu
Mike McCauley Mike McCauley
AirSpayce Pty Ltd AirSpayce Pty Ltd
9 Bulbul Place 9 Bulbul Place
Currumbin Waters QLD 4223 Currumbin Waters QLD 4223
AUSTRALIA Australia
Phone: +61 7 5598 7474 Phone: +61 7 5598 7474
EMail: mikem@airspayce.com Email: mikem@airspayce.com
URI: http://www.airspayce.com URI: http://www.airspayce.com
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