draft-ietf-radext-dynamic-discovery-05.txt   draft-ietf-radext-dynamic-discovery-06.txt 
RADIUS Extensions Working Group S. Winter RADIUS Extensions Working Group S. Winter
Internet-Draft RESTENA Internet-Draft RESTENA
Intended status: Experimental M. McCauley Intended status: Experimental M. McCauley
Expires: June 16, 2013 OSC Expires: August 29, 2013 OSC
December 13, 2012 February 25, 2013
NAI-based Dynamic Peer Discovery for RADIUS/TLS and RADIUS/DTLS NAI-based Dynamic Peer Discovery for RADIUS/TLS and RADIUS/DTLS
draft-ietf-radext-dynamic-discovery-05 draft-ietf-radext-dynamic-discovery-06
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 can be used in conjunction with RADIUS/TLS and for a given realm. It is used in conjunction with either RADIUS/TLS
RADIUS/DTLS. and RADIUS/DTLS.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 16, 2013. This Internet-Draft will expire on August 29, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2013 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 . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. DNS-based NAPTR/SRV Peer Discovery . . . . . . . . . . . . . . 3 2. DNS-based NAPTR/SRV Peer Discovery . . . . . . . . . . . . . 3
2.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Applicability . . . . . . . . . . . . . . . . . . . . . . 3
2.2. DNS RR definition . . . . . . . . . . . . . . . . . . . . 3 2.2. DNS RR definition . . . . . . . . . . . . . . . . . . . . 3
2.3. Realm to RADIUS server resolution algorithm . . . . . . . 6 2.3. Realm to RADIUS server resolution algorithm . . . . . . . 6
2.3.1. Input . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3.1. Input . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3.2. Output . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3.2. Output . . . . . . . . . . . . . . . . . . . . . . . 7
2.3.3. Algorithm . . . . . . . . . . . . . . . . . . . . . . 7 2.3.3. Algorithm . . . . . . . . . . . . . . . . . . . . . . 7
2.3.4. Validity of results . . . . . . . . . . . . . . . . . 8 2.3.4. Validity of results . . . . . . . . . . . . . . . . . 8
2.3.5. Delay considerations . . . . . . . . . . . . . . . . . 9 2.3.5. Delay considerations . . . . . . . . . . . . . . . . 9
2.3.6. Example . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.6. Example . . . . . . . . . . . . . . . . . . . . . . . 9
3. Security Considerations . . . . . . . . . . . . . . . . . . . 11 3. Security Considerations . . . . . . . . . . . . . . . . . . . 11
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
5. Normative References . . . . . . . . . . . . . . . . . . . . . 11 5. Normative References . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
RADIUS in all its current transport variants (RADIUS/UDP, RADIUS/TLS,
RADIUS/DTLS) requires manual configuration of all peers (clients,
servers).
Where RADIUS forwarding servers are in use, the number of realms to
be forwarded and the corresponding number of servers to configure may
be significant. Where new realms with new servers are added or
details of existing servers change on a regular basis, maintaining a
single monolithic configuration file for all these details may prove
too cumbersome to be useful.
Furthermore, in cases where a roaming consortium consists of
independently working branches, each with their own forwarding
servers, and who add or change their realm lists at their own
discretion, there is additional complexity in synchronising the
changed data across all branches.
These situations can benefit significantly from a distributed
mechanism for storing realm and server reachability information.
This document describes one such mechanism: storage of realm-to-
server mappings in DNS.
This document does not specify how to verify that server information
which was retrieved from DNS was from an authorised party; e.g. an
organisation which is not at all part of a given roaming consortium
may alter its own DNS records to yield a result for its own realm.
RADIUS/TLS and RADIUS/DTLS have their own ways how to verify that a
contacted peer is authorised (e.g. by presenting PKIX certificates
from a agreed-upon CA).
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
skipping to change at page 3, line 30 skipping to change at page 3, line 32
RADIUS/TLS Server: a RADIUS/TLS [RFC6614] instance which listens on a RADIUS/TLS Server: a RADIUS/TLS [RFC6614] instance which 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
2. DNS-based NAPTR/SRV Peer Discovery 2. DNS-based NAPTR/SRV Peer Discovery
2.1. Applicability 2.1. Applicability
Dynamic server discovery as defined in this document is only Dynamic server discovery as defined in this document is only
applicable for AAA transactions where a RADIUS server receives a applicable for AAA transactions where a RADIUS entity which acts as a
request with a realm for which no home RADIUS server is known. I.e. forwarding server for one or more realms receives a request with a
where static server configuration does not contain a known home realm for which it is not authoritative, and which no explicit next
authentication server, or where the server configuration explicitly hop is configured. Furthermore, it is only applicable for new user
states that the realm destination is to be looked up dynamically. sessions, i.e. for the initial Access-Request. Subsequent messages
Furthermore, it is only applicable for new user sessions, i.e. for concerning this session, for example Access-Challenges and Access-
the initial Access-Request. Subsequent messages concerning this Accepts use the previously-established communication channel between
session, for example Access-Challenges and Access-Accepts use the client and server.
previously-established communication channel between client and
server.
2.2. DNS RR definition 2.2. DNS 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 SRV records. When both are defined, the (see [RFC3958]) or SRV records. When both are defined, the
resolution algorithm prefers S-NAPTR results (see Section 2.3 below). resolution algorithm prefers S-NAPTR results (see Section 2.3 below).
This specification defines three S-NAPTR service tags: This specification defines three S-NAPTR service tags:
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
skipping to change at page 4, line 39 skipping to change at page 4, line 35
| | in [I-D.ietf-radext-dtls] | | | in [I-D.ietf-radext-dtls] |
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
Figure 2: List of Protocol Tags Figure 2: 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 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.
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): "_service._proto" part of an SRV RR):
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
| 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] |
| - - - - - - - - | - - - - - - - - - - - - - - - - - - - - | | - - - - - - - - | - - - - - - - - - - - - - - - - - - - - |
| _radiustls._udp | RADIUS transported over DTLS as defined | | _radiustls._udp | RADIUS transported over DTLS as defined |
| | in [I-D.ietf-radext-dtls] | | | in [I-D.ietf-radext-dtls] |
+-----------------+-----------------------------------------+ +-----------------+-----------------------------------------+
Figure 3: List of SRV Labels Figure 3: List of SRV Labels
It is expected that in most cases, the label used for the records is It is expected that in most cases, the SRV and/or NAPTR label used
the DNS representation (punycode) of the literal realm name for which for the records is the DNS A-label representation of the literal
the server is the 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
[RFC5891]).
However, arbitrary other labels may be used if, for example, a However, arbitrary other SRV and/or NAPTR labels may be used if, for
roaming consortium uses realm names which are not associated to DNS example, a roaming consortium uses realm names which are not
names or special-purpose consortia where a globally valid discovery associated to DNS names or special-purpose consortia where a globally
is not a use case. Such other labels require a consortium-wide valid discovery is not a use case. Such other labels require a
agreement about the transformation from realm name to lookup label. consortium-wide agreement about the transformation from realm name to
lookup label.
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" "" example.com. IN NAPTR 50 50 "s" "aaa+auth:radius.tls" ""
_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. "Bad, Inc." is part of the consortium. On the realm names. "Bad, Inc." is part of the consortium. On the
consortium's DNS server, realm bad.example might have the consortium's DNS server, realm bad.example might have the
following DNS entries: following DNS entries:
bad.example IN NAPTR 50 50 "a" "aaa+auth:radius.dtls" "" bad.example IN NAPTR 50 50 "a" "aaa+auth:radius.dtls" ""
"very.bad.example" very.bad.example
c. The eduroam consortium uses realms based on DNS, but provides its c. The eduroam consortium uses realms based on DNS, but provides its
services to a closed community only. However, a AAA domain services to a closed community only. However, a AAA domain
participating in eduroam may also want to expose AAA services to participating in eduroam may also want to expose AAA services to
other, general-purpose, applications (on the same or other RADIUS other, general-purpose, applications (on the same or other RADIUS
servers). Due to that, the eduroam consortium uses the service servers). Due to that, the eduroam consortium uses the service
tag "x-eduroam" for authentication purposes and eduroam RADIUS tag "x-eduroam" for authentication purposes and eduroam RADIUS
servers use this tag to look up other eduroam servers. An servers use this tag to look up other eduroam servers. An
eduroam participant example.org which also provides general- eduroam participant example.org which also provides general-
purpose AAA on a different server uses the general "aaa+auth" purpose AAA on a different server uses the general "aaa+auth"
skipping to change at page 7, line 11 skipping to change at page 7, line 11
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 @
Usage of multiple @ separators
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 which fail the conversion rules as per [RFC5891]
UTF-8 realms which end with a . ("dot") character. UTF-8 realms which 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.
2.3.2. Output 2.3.2. Output
Output O of the algorithm is a set of the tuple {hostname; port; Output O of the algorithm is a set of tuples {hostname; port; order/
order/preference; TTL} - the set can be empty. preference; TTL} - the set can be empty.
2.3.3. Algorithm 2.3.3. 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. Optional: modify R according to agreed consortium procedures 3. Optional: modify R according to agreed consortium procedures
4. Using the host's name resolution library, perform a NAPTR query 4. Using the host's name resolution library, perform a NAPTR query
for R (see "Delay considerations" below). The name resolution for R (see "Delay considerations" below). The name resolution
library may need to convert R to a different respresentation, library may need to convert R to a different respresentation,
depending on the resolution backend used. If no result, depending on the resolution backend used. If no result,
continue at step 9. If name resolution returns with error, O = continue at step 9. If name resolution returns with error, O =
{ } and terminate. { empty set } and terminate.
5. Extract NAPTR records with service tag "aaa+auth", "aaa+acct", 5. Extract NAPTR records with service tag "aaa+auth", "aaa+acct",
"aaa+dynauth" as appropriate. Keep note of the remaining TTL of "aaa+dynauth" as appropriate. Keep note of the remaining TTL of
each of the discovered NAPTR records. each of the discovered NAPTR records.
6. If no result, continue at step 9. 6. If no records found, continue at step 9.
7. Evaluate NAPTR result(s) for desired protocol tag, perform 7. Evaluate NAPTR result(s) for desired protocol tag, perform
subsequent lookup steps until lookup yields one or more subsequent lookup steps until lookup yields one or more
hostnames. O = (set of {hostname; port; order/preference; hostnames. O' = (set of {hostname; port; order/preference;
min{all TTLs that led to this result} } for all lookup results). min{all TTLs that led to this result} } for all lookup results).
Keep note of the remaining TTL of each of the discovered records Keep note of the remaining TTL of each of the discovered records
(e.g. SRV and AAAA). (e.g. SRV and AAAA).
8. Terminate. 8. Proceed with step 15.
9. Generate R' = (prefix R with "_radiustls._tcp." or 9. Generate R' = (prefix R with "_radiustls._tcp." or
"_radiustls._udp") "_radiustls._udp")
10. Using the host's name resolution library, perform SRV lookup 10. Using the host's name resolution library, perform SRV lookup
with R' as label (see "Delay considerations" below). Keep note with R' as label (see "Delay considerations" below). Keep note
of the TTL of each of the discovered SRV records. of the TTL of each of the discovered SRV records.
11. If name resolution returns with error, O = { } and terminate. 11. If name resolution returns with error, O = { empty set } and
terminate.
12. If no result, O = {} and terminate. 12. If no result, O = { empty set } and terminate.
13. Perform subsequent lookup steps until lookup yields one or more 13. O' = (set of {hostname; port; order/preference; min{all TTLs
hostnames (see "Delay considerations" below). Keep note of the that led to this result} } for all hostnames).
TTL of each of the discovered records.
14. O = (set of {hostname; port; order/preference; min{all TTLs that 14. Generate O by resoving hostnames to corresponding A and/or AAAA
led to this result} } for all hostnames). Terminate. addresses: O = (set of {IP address; port; order/preference;
min{all TTLs that led to this result}} for all hostnames ).
15. For each element in O, test if the original request which
triggered dynamic discovery was received on {IP address; port}.
If yes, O = { empty set }, log error, Terminate. If no, O is
the result of dynamic discovery. Terminate.
2.3.4. Validity of results 2.3.4. Validity of results
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. To allow it is safe to rely on the results of the name resolution. When a
for a change of configuration, a RADIUS server SHOULD re-execute the connection is open and the smallest of the TTL values which were used
algorithm above after the lowest of the TTL values that are for discovering the server has not expired, subsequent new user
associated with this connection have expired. The server MAY keep sessions for the realm which corresponds to that open connection
the session open during this re-assessment to avoid closure and SHOULD re-use the existing connection and SHOULD NOT re-execute the
dynamic discovery algorithm nor open a new connection. To allow for
a change of configuration, a RADIUS server SHOULD re-execute the
dynamic discovery algorithm after the lowest of the TTL values that
are associated with this connection have expired. The server MAY
keep the session open during this re-assessment to avoid closure and
immediate re-opening of the connection should the result not have immediate re-opening of the connection should the result not have
changed. changed.
Should the algorithm above terminate with an empty set (but no Should the algorithm above terminate with an empty set (but no
error), the RADIUS server SHOULD NOT attempt another execution of error), the RADIUS server SHOULD NOT attempt another execution of
this algorithm for the same target realm before the negative TTL has this algorithm for the same target realm before the negative TTL has
expired. expired.
Should the algorithm above terminate due to an error with no TTL Should the algorithm above terminate due to an error with no TTL
value known (e.g. DNS SERVFAIL), the RADIUS server SHOULD NOT value known (e.g. DNS SERVFAIL), the RADIUS server SHOULD NOT
attempt another execution of this algorithm for the same target realm attempt another execution of this algorithm for the same target realm
before a configurable timeout interval has passed. before a configurable timeout interval has passed.
2.3.5. Delay considerations 2.3.5. 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 time-out of its name resolution resolution library signals a time-out of its name resolution
algorithms; instead, implementations of NAI discovery SHOULD algorithms; instead, implementations of NAI discovery SHOULD
terminate the algorithm after the fixed upper bound of time of three terminate the algorithm after the fixed upper bound of time of three
seconds. If no final output of the algorithm is available after this seconds. If no final output of the algorithm is available after this
timeout, the RADIUS server MUST assume the empty set as a result and timeout, the RADIUS server MUST assume the empty set as a result and
treat the pending request according to its static configuration treat the pending request according to its static configuration
(e.g., fallback to a default route to a home server). Execution of (e.g., fallback to a default route to a home server). Execution of
the NAI discovery algorithm SHOULD be non-blocking (i.e. allow other the NAI discovery algorithm SHOULD be non-blocking (i.e. allow other
requests to be processed in parallel to the execution of the requests to be processed in parallel to the execution of the
algorithm). algorithm).
2.3.6. Example 2.3.6. Example
Example: Assume a user from the Technical University of Munich, Example: Assume
Germany, has a RADIUS User-Name of
"foobar@tu-m[U+00FC]nchen.example". The name resolution library on
the RADIUS client uses DNS for name resolution. If DNS contains the
following records:
xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s" "aaa+ a user from the Technical University of Munich, Germany, has a
auth:radius.tls" "" _radiustls._tcp.xn--tu-mnchen-t9a.example. RADIUS User-Name of "foobar@tu-m[U+00FC]nchen.example".
xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s" "fooservice: The name resolution library on the RADIUS forwarding server does
bar.dccp" "" _abc._def.xn--tu-mnchen-t9a.example. not have the realm tu-m[U+00FC]nchen.example in its forwarding
configuration, but uses DNS for name resolution and has configured
the use of Dynamic Discovery to discover RADIUS servers.
It is IPv6-enabled and prefers AAAA records over A records.
It is listening for incoming RADIUS/TLS requests on 192.37.5.1,
TCP/2083.
If DNS contains the following records:
xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s"
"aaa+auth:radius.tls" "" _radiustls._tcp.xn--tu-mnchen-
t9a.example.
xn--tu-mnchen-t9a.example. IN NAPTR 50 50 "s"
"fooservice:bar.dccp" "" _abc._def.xn--tu-mnchen-t9a.example.
_radiustls._tcp.xn--tu-mnchen-t9a.example. IN SRV 0 10 2083 _radiustls._tcp.xn--tu-mnchen-t9a.example. IN SRV 0 10 2083
radsec.xn--tu-mnchen-t9a.example. radsec.xn--tu-mnchen-t9a.example.
_radiustls._tcp.xn--tu-mnchen-t9a.example. IN SRV 0 20 2083 _radiustls._tcp.xn--tu-mnchen-t9a.example. IN SRV 0 20 2083
backup.xn--tu-mnchen-t9a.example. backup.xn--tu-mnchen-t9a.example.
radsec.xn--tu-mnchen-t9a.example. IN AAAA 2001:0DB8::202:44ff: radsec.xn--tu-mnchen-t9a.example. IN AAAA
fe0a:f704 2001:0DB8::202:44ff:fe0a:f704
radsec.xn--tu-mnchen-t9a.example. IN A 192.0.2.3 radsec.xn--tu-mnchen-t9a.example. IN A 192.0.2.3
backup.xn--tu-mnchen-t9a.example. IN A 192.0.2.7 backup.xn--tu-mnchen-t9a.example. IN A 192.0.2.7
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- 4. [name resolution library converts R to xn--tu-mnchen-
t9a.example] Query result: ( 50 50 "s" "aaa+auth:radius.tls" "" t9a.example] Query result: ( 50 50 "s" "aaa+auth:radius.tls" ""
_radiustls._tcp.xn--tu-mnchen-t9a.example. ; 50 50 "s" _radiustls._tcp.xn--tu-mnchen-t9a.example. ; 50 50 "s"
"fooservice:bar.dccp" "" _abc._def.xn--tu-mnchen-t9a.example. ) "fooservice:bar.dccp" "" _abc._def.xn--tu-mnchen-t9a.example. )
5. Result: 50 50 "s" "aaa+auth:radius.tls" "" _radiustls._tcp.xn-- 5. Result: 50 50 "s" "aaa+auth:radius.tls" "" _radiustls._tcp.xn
tu-mnchen-t9a.example. --tu-mnchen-t9a.example.
6. NOOP 6. NOOP
7. O = {(radsec.xn--tu-mnchen-t9a.example.; 2083; 10; TTL 7. O' = {(radsec.xn--tu-mnchen-t9a.example.; 2083; 10; TTL
A),(backup.xn--tu-mnchen-t9a. example.;2083; 20; TTL B)} A),(backup.xn--tu-mnchen-t9a. example.;2083; 20; TTL B)}
8. Terminate. 8. Go to step 15.
9. (not executed) 9. (not executed)
10. (not executed) 10. (not executed)
11. (not executed) 11. (not executed)
12. (not executed) 12. (not executed)
13. (not executed) 13. (not executed)
14. (not executed) 14. O = {(2001:0DB8::202:44ff:fe0a:f704; 2083; 10; TTL
A),(192.0.2.7; 2083; 20; TTL B)}
15. O = {(2001:0DB8::202:44ff:fe0a:f704; 2083; 10; TTL
A),(192.0.2.7; 2083; 20; TTL B)}. Terminate.
The implementation will then attempt to connect to two servers, with The implementation will then attempt to connect to two servers, with
preference to radsec.xn--tu-mnchen-t9a.example.:2083, using either preference to radsec.xn--tu-mnchen-t9a.example.:2083, using either
the AAAA or A addresses depending on the host configuration and its the AAAA or A addresses depending on the host configuration and its
IP stack's capabilities. IP stack's capabilities.
3. Security Considerations 3. Security Considerations
When using DNS without DNSSEC security extensions, the replies to When using DNS without DNSSEC security extensions, the replies to
NAPTR, SRV and A/AAAA requests as described in section Section 2 can NAPTR, SRV and A/AAAA requests as described in section Section 2 can
skipping to change at page 11, line 35 skipping to change at page 12, line 14
* aaa+acct * aaa+acct
* aaa+dynauth * aaa+dynauth
o S-NAPTR Application Protocol Tags registry o S-NAPTR Application Protocol Tags registry
* radius.tls * radius.tls
* radius.dtls * radius.dtls
This document reserves the use of the "_radiustls" Service label. This document reserves the use of the "_radiustls" and "_radiusdtls"
Service labels.
This document requests the creation of a new IANA registry named This document requests the creation of a new IANA registry named
"RADIUS/TLS SRV Protocol Registry" with the following initial "RADIUS/TLS SRV Protocol Registry" with the following initial
entries: entries:
o _tcp o _tcp
o _udp o _udp
5. Normative References 5. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Indicate Requirement Levels", BCP 14, Requirement Levels", BCP 14, RFC 2119, March 1997.
RFC 2119, March 1997.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W.
Simpson, "Remote Authentication Dial In User [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
Service (RADIUS)", RFC 2865, June 2000. "Remote Authentication Dial In User Service (RADIUS)", RFC
2865, June 2000.
[RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866, [RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.
June 2000.
[RFC3958] Daigle, L. and A. Newton, "Domain-Based [RFC3958] Daigle, L. and A. Newton, "Domain-Based Application
Application Service Location Using SRV RRs Service Location Using SRV RRs and the Dynamic Delegation
and the Dynamic Delegation Discovery Service Discovery Service (DDDS)", RFC 3958, January 2005.
(DDDS)", RFC 3958, January 2005.
[RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, [RFC5176] Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B.
D., and B. Aboba, "Dynamic Authorization Aboba, "Dynamic Authorization Extensions to Remote
Extensions to Remote Authentication Dial In Authentication Dial In User Service (RADIUS)", RFC 5176,
User Service (RADIUS)", RFC 5176, January 2008.
January 2008.
[RFC5580] Tschofenig, H., Adrangi, F., Jones, M., Lior, [RFC5580] Tschofenig, H., Adrangi, F., Jones, M., Lior, A., and B.
A., and B. Aboba, "Carrying Location Objects Aboba, "Carrying Location Objects in RADIUS and Diameter",
in RADIUS and Diameter", RFC 5580, RFC 5580, August 2009.
August 2009.
[RFC5891] Klensin, J., "Internationalized Domain Names [RFC5891] Klensin, J., "Internationalized Domain Names in
in Applications (IDNA): Protocol", RFC 5891, Applications (IDNA): Protocol", RFC 5891, August 2010.
August 2010.
[I-D.ietf-radext-dtls] DeKok, A., "DTLS as a Transport Layer for [I-D.ietf-radext-dtls]
RADIUS", draft-ietf-radext-dtls-02 (work in DeKok, A., "DTLS as a Transport Layer for RADIUS", draft-
progress), July 2012. ietf-radext-dtls-02 (work in progress), July 2012.
[RFC6614] Winter, S., McCauley, M., Venaas, S., and K. [RFC6614] Winter, S., McCauley, M., Venaas, S., and K. Wierenga,
Wierenga, "Transport Layer Security (TLS) "Transport Layer Security (TLS) Encryption for RADIUS",
Encryption for RADIUS", RFC 6614, May 2012. RFC 6614, May 2012.
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
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