The eap.arpa. domain and EAP provisioning
draft-ietf-emu-eap-arpa-10
| Document | Type | Active Internet-Draft (emu WG) | |
|---|---|---|---|
| Author | Alan DeKok | ||
| Last updated | 2025-10-08 (Latest revision 2025-09-04) | ||
| Replaces | draft-dekok-emu-eap-arpa | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Reviews |
DNSDIR Telechat review
(of
-09)
by Patrick Mevzek
Ready w/nits
GENART IETF Last Call review
(of
-06)
by Ines Robles
Almost ready
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Peter E. Yee | ||
| Shepherd write-up | Show Last changed 2025-01-01 | ||
| IESG | IESG state | RFC Ed Queue | |
| Action Holders |
(None)
|
||
| Consensus boilerplate | Yes | ||
| Telechat date | (None) | ||
| Responsible AD | Paul Wouters | ||
| Send notices to | peter@akayla.com | ||
| IANA | IANA review state | IANA OK - Actions Needed | |
| IANA action state | RFC-Ed-Ack | ||
| RFC Editor | RFC Editor state | EDIT | |
| Details |
draft-ietf-emu-eap-arpa-10
EMU Working Group A. DeKok
Internet-Draft InkBridge Networks
Updates: 5216, 9140, 9190 (if approved) 4 September 2025
Intended status: Standards Track
Expires: 8 March 2026
The eap.arpa. domain and EAP provisioning
draft-ietf-emu-eap-arpa-10
Abstract
This document defines the eap.arpa. domain for use only in Network
Access Identifiers (NAIs) as a way for Extensible Authentication
Protocol (EAP) peers to signal to EAP servers that they wish to
obtain limited, and unauthenticated, network access. EAP peers
signal which kind of access is required via certain predefined
identifiers which use the Network Access Identifier (NAI) format of
RFC 7542. A table of identifiers and meanings is defined, which
includes entries for RFC 9140.
This document updates RFC5216 and RFC9190 to define an
unauthenticated provisioning method. Those specifications suggested
that such a method has possible, but they did not define how it would
be done. This document also updates RFC9140 to deprecate "eap-
noob.arpa", and replace it with "@noob.eap.arpa"
About This Document
This note is to be removed before publishing as an RFC.
Status information for this document may be found at
https://datatracker.ietf.org/doc/draft-ietf-emu-eap-arpa/.
Discussion of this document takes place on the EMU Working Group
mailing list (mailto:emut@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/emut/. Subscribe at
https://www.ietf.org/mailman/listinfo/emut/.
Source for this draft and an issue tracker can be found at
https://github.com/freeradius/eap-arpa.git.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
DeKok Expires 8 March 2026 [Page 1]
Internet-Draft eap.arpa September 2025
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 https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 8 March 2026.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Background and Rationale . . . . . . . . . . . . . . . . 4
1.1.1. Review of Existing Functionality . . . . . . . . . . 4
1.1.2. Taxonomy of Provisioning Types . . . . . . . . . . . 5
1.1.3. Rationale for Provisioning over EAP . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1. The eap.arpa realm . . . . . . . . . . . . . . . . . . . 6
3.2. The realm field . . . . . . . . . . . . . . . . . . . . . 7
3.3. The username field . . . . . . . . . . . . . . . . . . . 8
3.4. Operation . . . . . . . . . . . . . . . . . . . . . . . . 8
3.4.1. EAP Peers . . . . . . . . . . . . . . . . . . . . . . 8
3.4.2. EAP Servers . . . . . . . . . . . . . . . . . . . . . 10
3.5. Other Considerations . . . . . . . . . . . . . . . . . . 12
3.6. Considerations for Provisioning Specifications . . . . . 12
3.6.1. Negotiation . . . . . . . . . . . . . . . . . . . . . 12
3.6.2. Renewal of Credentials . . . . . . . . . . . . . . . 12
3.7. Notes on AAA Routability . . . . . . . . . . . . . . . . 13
4. Interaction with EAP Methods . . . . . . . . . . . . . . . . 13
4.1. High Level Requirements . . . . . . . . . . . . . . . . . 14
DeKok Expires 8 March 2026 [Page 2]
Internet-Draft eap.arpa September 2025
4.2. EAP-TLS . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.3. EAP-NOOB . . . . . . . . . . . . . . . . . . . . . . . . 15
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
5.1. .arpa updates . . . . . . . . . . . . . . . . . . . . . . 16
5.1.1. Deprecating eap-noob.arpa . . . . . . . . . . . . . . 16
5.1.2. Defining the eap.arpa. Domain . . . . . . . . . . . 16
5.2. EAP Provisioning Identifiers Registry . . . . . . . . . . 18
5.2.1. Initial Values . . . . . . . . . . . . . . . . . . . 18
5.3. Guidelines for Designated Experts . . . . . . . . . . . . 19
5.3.1. NAIs . . . . . . . . . . . . . . . . . . . . . . . . 19
5.4. Method Type . . . . . . . . . . . . . . . . . . . . . . . 20
5.5. Designated Experts . . . . . . . . . . . . . . . . . . . 20
5.6. Organization Self Assignment . . . . . . . . . . . . . . 20
6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 21
7. Security Considerations . . . . . . . . . . . . . . . . . . . 22
7.1. On-Path Attackers and Impersonation . . . . . . . . . . . 22
7.2. Provisioning is Unauthenticated . . . . . . . . . . . . . 22
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 23
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
9.1. Normative References . . . . . . . . . . . . . . . . . . 23
9.2. Informative References . . . . . . . . . . . . . . . . . 24
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction
In most uses, EAP [RFC3748] requires that the EAP peers have pre-
provisioned credentials. Without credentials, the device cannot
obtain network access in order to be provisioned with credentials.
This limitation creates a bootstrapping problem.
This specification addresses that bootstrapping problem. It creates
a framework for predefined "well-known" provisioning credentials, and
instantiates that framework for two mechanisms.
Clients can submit these predefined provisioning credentials to a
server in order to obtain limited network access. At the same time,
servers can know in advance that these credentials are to be used
only for provisioning, and avoid granting unrestricted network access
to peers which submit these credentials.
The device can either use the EAP channel itself for provisioning, as
with TEAP [RFC7170], or the EAP server can give the device access to
a limited captive portal such as with [RFC8952]. Once the device is
provisioned, it can use those provisioned credentials to obtain full
network access.
DeKok Expires 8 March 2026 [Page 3]
Internet-Draft eap.arpa September 2025
The predefined provisioning credentials use a generic identity
format. Identifiers in this space are generically referred to as
"EAP Provisioning Identifiers" (EPI).
Since the identity is predefined and used only for unauthenticated
network access, there is little benefit to specifying predefined
passwords. Where supported by the underlying EAP method, this
specification provides for password-less access. Where passwords are
required, the password is defined to be the same as the identity.
1.1. Background and Rationale
In this section, we provide background on the existing functionality,
and describe why it was necessary to define provisioning methods for
EAP.
1.1.1. Review of Existing Functionality
For EAP-TLS, both [RFC5216] Section 2.1.1 and [RFC9190] provide for
"peer unauthenticated access". However, those documents define no
way for a peer to signal that it is requesting such access. The
presumption is that the peer connects with some value for the EAP
Identity, but without using a client certificate. The EAP server is
then supposed to determine that the peer is requesting
unauthenticated access, and take the appropriate steps to limit
authorization.
There appears to be no EAP peer or server implementations which
support such access, since there is no defined way to perform any of
the steps required, i.e., to signal that this access is desired, and
then limit access.
Wi-Fi Alliance has defined an unauthenticated EAP-TLS method, using a
vendor-specific EAP method as part of HotSpot 2.0r2 [HOTSPOT].
However, there appears to be few deployments of this specification.
EAP-NOOB [RFC9140] takes this process a step further. It defines
both a way to signal that provisioning is desired, and also a way to
exchange provisioning information within EAP-NOOB. That is, there is
no need for the device to obtain limited network access, as all of
the provisioning is done inside of the EAP-NOOB protocol.
DeKok Expires 8 March 2026 [Page 4]
Internet-Draft eap.arpa September 2025
Tunnel Extensible Authentication Protocol (TEAP) [RFC7170] provides
for provisioning via an unauthenticated TLS tunnel. That document
provides for a server unauthenticated provisioning mode, but the
inner TLS exchange requires that both ends authenticate each other.
There are ways to provision a certificate, but the peer must still
authenticate itself to the server with pre-existing credentials. As
a result, any provisioning method which uses TEAP will have to
address this limitation.
1.1.2. Taxonomy of Provisioning Types
There are two scenarios where provisioning can be done. The first is
where provisioning is done within the EAP method, as with EAP-NOOB
[RFC9140]. The second is where EAP is used to obtain limited network
access (e.g. as with a captive portal). That limited network access
is then used to run IP based provisioning over more complex
protocols.
1.1.3. Rationale for Provisioning over EAP
It is often useful to do all provisioning inside of EAP, because the
EAP / AAA admin does not have control over the network. It is not
always possible to define a captive portal where provisioning can be
done. As a result, we need to be able to perform provisioning via
EAP, and not via some IP protocol.
2. Terminology
EAP Provisioning Identifier
The EAP Provisioning Identifier is defined to be a strict subset
of the Network Access Identifier (NAI) [RFC7542]. The EPI is an
NAI which is a subdomain of "eap.arpa". The "realm" portion of
the NAI is defined in [RFC7542], Section 2.2, which is a more
restrictive subset of the domain name conventions specified in
[STD13].
Readers of this document should note that the realm portion of the
NAI is different from a domain name. In addition to the character
set being more limited, the realm portion of the NAI does not
include a trailing ".".
eap.arpa
The realm portion of the NAI.
This document uses the term "eap.arpa realm" when using that name
within the contect of an NAI.
DeKok Expires 8 March 2026 [Page 5]
Internet-Draft eap.arpa September 2025
eap.arpa.
The domain name "eap.arpa.".
This document uses the term "eap.arpa. domain " when using that
name within the contect of the DNS. The trailing "." is added for
consistency with DNS specifications.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Overview
A device which has no device-specific credentials can use a
predefined provisioning identifier in Network Access Identifier (NAI)
format [RFC7542]. The NAI is composed of two portions, the
utf8-username, and the utf8-realm domain. For simplicity here, we
refer to these as the "username" and "realm" fields.
The realm is chosen to be independent of, and unused by, any existing
organization, and thus to be usable by all organizations. The realm
needs to be one which is not automatically proxied by any existing
Authentication, Authorization, and Accounting (AAA) proxy framework
as defined in [RFC7542], Section 3. The realm also needs to be one
which does not return results for [RFC7585] dynamic discovery.
This specification does not, however, forbid routing of packets for
NAIs in the eap.arpa realm. Instead, it leaves such routing up to
individual organizations.
This specification is fully compatible with all known EAP
implementations, so it is fail-safe. When presented with a peer
wishing to use this specification, existing implementations will
return EAP Failure, and will not otherwise misbehave.
3.1. The eap.arpa realm
This document defines the eap.arpa realm as being used for
provisioning within EAP. A similar domain has previously been used
for EAP-NOOB [RFC9140], as "eap-noob.arpa". This document extends
that concept, and standardizes the practices surrounding it,
NOTE: the "arpa" domain is controlled by the IAB. Allocation of the
eap.arpa. domain name requires agreement from the IAB.
DeKok Expires 8 March 2026 [Page 6]
Internet-Draft eap.arpa September 2025
RFC-EDITOR: This text can be updated on publication to indicate that
the IAB has approved it.
3.2. The realm field
The NAIs defined by this specification use the [RFC7542] "realm"
field to signal the behavior being requested; in particular, the
subdomain under the eap.arpa. domain allows for different requested
methods to be distinguished. The subdomain in the realm field is
assigned via the EAP Provisioning Identifier Registry [EAPREG], which
is defined in Section 5.2. The subdomain MUST follow the syntax
defined in [RFC7542], Section 2.2, which is a more restrictive subset
of the domain name conventions specified in [STD13].
Where possible, the first subdomain of the eap.arpa. domain SHOULD
use the EAP method name, as defined in the IANA Extensible
Authentication Protocol (EAP) Registry group, "Method Types"
registry. However, the EAP registry does not follow the domain name
conventions specified in [STD13], so it is not always possible to
make a "one-to-one" mapping between the Method Type name and a
subdomain of the eap.arpa. domain.
Where it is not possible to make a direct mapping between the EAP
Method Type name due to the EAP Method Type name not matching the
[RFC7542], Section 2.2 format, the NAI which is defined in the EAP
Provisioning Identifiers registry MUST use a realm name which is
similar enough to allow the average reader to understand which EAP
Method Type is being used.
Additional subdomains are permitted in the realm, which permit
vendors and Standards Development organizations (SDOs) the ability to
self-assign a delegated range of identifiers which do not conflict
with other identifiers.
Any realm defined in this registry (e.g. "tls.eap.arpa") also
implicitly defines a sub-realm "v." (e.g. "v.tls.eap.arpa"). Vendors
or SDOs can self-allocate within the "v." realm, using realms that
they own. For example, a company that owns the "example.com." domain
could self-allocate and use the realm "example.com.v.tls.eap.arpa".
See Section 5.6 for more discussion of this topic.
This specification does not make any provisions for private-use
realms. The "v." sub-realm is sufficient for all private uses.
DeKok Expires 8 March 2026 [Page 7]
Internet-Draft eap.arpa September 2025
Experimental provisioning methods MUST be defined within the
appropriate vendors name space. For drafts within the IETF, the
"ietf.org" vendor space MUST be used. Different uses SHOULD be
distinguished by using the name of a working group or document, such
as "emu.ietf.org.v.eap.arpa".
3.3. The username field
The username field is dependent on the EAP method being used for
provisioning. For example, [RFC9140] uses the username "noob".
Other EAP methods MAY omit the username as recommended in [RFC7542].
The username of "anonymous" is NOT RECOMMENDED for specifications
using this format, even though it is permitted by [RFC7542]. The
name "anonymous" is widely used in NAIs today, and we wish to avoid
confusion.
The username field is assigned via the EAP Provisioning Identifier
Registry which is defined in Section 5.2. The username field MAY be
empty, or else hold a fixed value. While [RFC7542] recommends
omitting the username portion for user privacy, the names here are
defined in public specifications. User privacy is therefore not
needed for provisioning identifiers, and the username field can be
publicly visible.
3.4. Operation
Having described the format and contents of NAIs in the eap.arpa
realm to define the EPI, we now describe how those EPIs are used by
EAP peers and EAP peers to signal provisioning information
3.4.1. EAP Peers
An EAP peer signals that it wishes a certain kind of provisioning by
using an EPI, along with an associated EAP method. The meaning of
the EPI, and behavior of the peer, are defined by a separate
specification. That specification will typically define both the
EPI, and the EAP method or methods which are used for provisioning.
The EPI used by the peer MUST be taken from an entry in the "EAP
Provisioning Identifiers" registry, and the EAP method used with that
NAI MUST match the corresponding EAP method from that same entry.
DeKok Expires 8 March 2026 [Page 8]
Internet-Draft eap.arpa September 2025
Where an EAP peer allows local selection of a provisioning method,
the EPI is defined by the provisioning method and not by the end
user. As a result, when a provisioning method is being selected, the
EAP peer MUST NOT have a configuration interface which lets the EAP
user identifier field be configured directly. Instead the user (or
some other process) chooses a provisioning method, and the EAP peer
then selects the EPI which matches that provisioning method.
While EAP peers allow users to enter user identifiers directly for
existing EAP methods, they MUST NOT check whether those identfiers
match any EPI. Any user who enters an identifier which matches an
EPI will either get rejected because the server does not support
provisioning, or the user will be placed into a captive portal.
There is no security or privacy issues with a user manually entering
an EPI as the user identifier.
When all goes well, running EAP with the EPI results in new
authentication credentials being provisioned. The peer then drops
its network connection, and re-authenticates using the newly
provisioned credentials. The user MAY be involved in this process,
but in general provisioning results in the EAP peer automatically
gaining network access using the provisioned credentials.
There are a number of ways in which provisioning can fail. One way
is when the server does not implement the provisioning method. EAP
peers therefore MUST track which provisioning methods have been
tried, and not repeat the same method to the same EAP server when
receiving an EAP Nak.
Peers MUST rate limit their provisioning attempts. If provisioning
fails, it is likely because provisioning is not available. Retrying
provisioning repeatedly in quick succession is not likely to change
the server behavior. Instead, it is likely to result in the peer
being blocked. The peer SHOULD retry provisioning no more than once
every few minutes, and SHOULD include jitter and exponential backoff
on its provisioning attempts.
Since there is no way to signal whether the failed provisioning is
due to a transient failure on the EAP server, or whether it is due to
the EAP server not supporting that provisioning method, EAP peers
SHOULD err on the side of long delays between retrying the same
provisioning method to an EAP server. EAP peers MAY retry a given
provisioning method after a sufficiently long interval that the EAP
server might have implemented the provisioning method, e.g., at least
a day, and perhaps no more than a month.
DeKok Expires 8 March 2026 [Page 9]
Internet-Draft eap.arpa September 2025
Another way for the provisioning method to fail is when the new
credentials do not result in network access. It is RECOMMENDED that
when peers are provisioned with credentials, that they immediately
try to gain network access using those credentials. That process
allows errors to be quickly discovered and addressed.
An EAP peer may have been provisioned with temporary credentials or
credentials that expire after some period of time (e.g., an X.509
certificate with notAfter date set). It SHOULD therefore attempt to
provision new credentials before the current set expires.
Unfortunately, any re-provisioning process with EAP will involve the
device dropping off from the "full" network, in order to connect to
the provisioning network. It is therefore RECOMMENDED that re-
provisioning methods be provided which can be used when the device
has full network access. See Section 3.6 for additional discussion
on this topic.
3.4.2. EAP Servers
An EAP session begins with the server receiving an initial EAP-
Request/Identity message. An EAP server supporting this
specification MUST examine the identity to see if it uses a realm
located under eap.arpa. If so, the identity is an EPI. Processing
of all other identities is unchanged by this specification.
If the server receives an EPI which is malformed, it MUST reply with
an EAP Failure, as per [RFC3748], Section 4.2. For example, an NAI
may end with the eap.arpa realm, but may also contain data which is
not permitted by the [RFC7542] format. Otherwise, the EPI is
examined to determine which provisioning method is being requested by
the peer.
If the server does not recognize the EPI requested by the peer, it
MUST reply with an EAP Nak of type zero (0). This reply indicates
that the requested provisioning method is not available. The server
also MUST reply with a Nak of type zero (0) as per [RFC3748],
Section 5.3.1, if the peer proposes an EAP method which is not
supported by the server, or is not recognized as being valid for that
provisioning method. The peer can then take any remedial action
which it determines to be appropriate.
Once the server accepts the provisioning method, it then replies with
an EAP method which MUST match the one associated with the EPI. The
EAP process then proceeds as per the EAP state machine outlined in
[RFC3748].
DeKok Expires 8 March 2026 [Page 10]
Internet-Draft eap.arpa September 2025
Implementations MUST treat peers using an EPI as untrusted, and
untrustworthy. Once such a peer is authenticated, it MUST be placed
into a limited network, such as a captive portal. The limited
network MUST NOT permit unrestricted network access. Implementations
should be aware of methods which bypass simple blocking, such as
tunneling data over DNS.
A secure provisioning network is one where only the expected traffic
is allowed, and all other traffic is blocked. The alternative of
blocking only selected "bad" traffic results in substantial security
failures. As most provisioning methods permit unauthenticated
devices to gain network access, these methods have a substantial
potential for abuse by malicious actors. As a result, the limited
network needs to be designed assuming that it will be abused by
malicious actor.
A limited network SHOULD also limit the duration of network access by
devices being provisioned. The provisioning process should be fairly
quick, and in the order of seconds to tens of seconds in duration.
Provisioning times longer than this likely indicate an issue, and it
may be useful to block the problematic device from the network.
A limited network SHOULD also limit the amount of data being
transferred by devices being provisioned, and SHOULD limit the
network services which are available to those devices. The
provisioning process generally does not need to download large
amounts of data, and similarly does not need access to a large number
of services.
Servers SHOULD rate limit provisioning attempts. A misbehaving peer
can be blocked temporarily, or even permanently. Implementations
SHOULD limit the total number of peers being provisioned at the same
time. There is no requirement for RADIUS servers to allow all peers
to connect without limit. Instead, peers are provisioned at the
discretion of the network being accessed, which may permit or deny
those devices based on reasons which are not explained to those
devices.
Implementations SHOULD use functionality such as the RADIUS Filter-Id
attribute ([RFC2865], Section 5.11) to limit network access for the
peer being provisioned, as discussed above in Section 3.4.2. For
ease of administration, the Filter-Id name could simply be the EPI,
or a similar name. Such consistency aids with operational
considerations when managing complex networks.
DeKok Expires 8 March 2026 [Page 11]
Internet-Draft eap.arpa September 2025
Implementations MUST prevent peers in the limited network from
communicating with each other. There is no reason for a system that
is being provisioned to communicate with anything other than the
provisioning server(s).
3.5. Other Considerations
Implementations MUST NOT permit EAP method negotiation with
provisioning credentials. That is, when an EPI is used, any EAP Nak
sent by a server must contain only EAP method zero (0). When an EAP
peer uses an EPI and receives an EAP Nak, any EAP methods given in
that Nak MUST be ignored.
While a server may support multiple provisioning methods, there is no
way in EAP to negotiate which provisioning method can be used. It is
also expected that the provisioning methods will be specific to a
particular type of peer device. That is, a given peer is likely to
support only one provisioning method.
As a result, there is no need to require a method for negotiating
provisioning methods.
3.6. Considerations for Provisioning Specifications
The operational considerations discussed above have a number of
impacts on specifications which define provisioning methods.
3.6.1. Negotiation
Specifications which define provisioning for an EAP method SHOULD
provide a method-specific process by which implementations can
negotiate a mutually acceptable provisioning method.
For the reasons noted above, however, we cannot make this suggestion
mandatory. If it is not possible for a provisioning method to define
any negotiation, then that limitation should not be a barrier to
publishing the specification.
3.6.2. Renewal of Credentials
Where a provisioning method is expected to create credentials that do
not expire, the specification SHOULD state this explicitly.
Where credentials expire, it is RECOMMENDED that specifications
provide guidance on how the credentials are to be updated. For
example, an EAP method could permit re-provisioning to be done as
part of a normal EAP authentication, using the currently provisioned
credentials.
DeKok Expires 8 March 2026 [Page 12]
Internet-Draft eap.arpa September 2025
It is RECOMMENDED that the provisioning methods provide for a method
which can be used without affecting network access. A specification
could define provisioning endpoints such as Enrollment over Secure
Transport (EST) [RFC7030], or Internet X.509 Public Key
Infrastructure Certificate Management Protocol (CMP) [RFC9810]. The
provisioning endpoints could be available both on the provisioning
network, and on the provisioned (i.e., normal) network. Such an
architecture means that devices can be re-provisioned without losing
network access.
3.7. Notes on AAA Routability
[RFC7542], Section 3 describes how the NAI allows authentication
requests to be routable within an AAA proxy system. While the EPI
uses the NAI format, the eap.arpa realm has been chosen because it is
not routable within an AAA proxy system.
When we say that the eap.arpa realm is not routable in an AAA proxy
system, we mean two different things. First, the eap.arpa. domain
does not exist within the DNS, so it will never be resolvable for
[RFC7585] dynamic discovery. Second, that the eap.arpa realm will
never be used by any administrator, as the administrator is unable to
satisfy the requirements of [RFC7542], Section 2.5 by registering the
realm within the DNS.
In addition, administrators will not have statically configured AAA
proxy routes for this domain. Where routes are added for this
domain, they will generally be used to implement this specification.
In order to avoid spurious DNS lookups, RADIUS servers supporting
[RFC7585] SHOULD perform filtering in the domains which are sent to
DNS. Specifically, names in the eap.arpa. domain MUST NOT be looked
up in DNS.
4. Interaction with EAP Methods
As the provisioning identifier is used within EAP, it necessarily has
interactions with, and effects on, the various EAP methods. This
section discusses those effects in more detail.
Some EAP methods require shared credentials such as passwords in
order to succeed. For example, both EAP-MSCHAPv2 (PEAP) and EAP-PWD
[RFC5931] perform cryptographic exchanges where both parties knowing
a shared password. Where password-based methods are used, the
password SHOULD be the same as the provisioning identifier, as there
are few reasons to define a method-specific password.
DeKok Expires 8 March 2026 [Page 13]
Internet-Draft eap.arpa September 2025
This requirement also applies to TLS-based EAP methods such as EAP
Tunneled Transport Layer Security (EAP-TTLS) and Protected Extensible
Authentication Protocol (PEAP). Where the TLS-based EAP method
provides for an inner identity and inner authentication method, the
credentials used there SHOULD be the provisioning identifier for both
the inner identity, and any inner password.
It is RECOMMENDED that provisioning be done via a TLS-based EAP
methods. TLS provides for authentication of the EAP server, along
with integrity and confidentiality protection for any provisioning
data exchanged in the tunnel. Similarly, if provisioning is done in
a captive portal outside of EAP, EAP-TLS permits the EAP peer to run
a full EAP authentication session while having nothing more than a
few certificate authorities (CAs) locally configured.
4.1. High Level Requirements
All provisioning methods which are specified within the eap.arpa.
domain MUST define a way to authenticate the server. This
authentication can happen either at the EAP layer (as with TLS-based
EAP methods), or after network access has been granted (if
credentials are provisioned over HTTPS).
Where TLS-based EAP methods are used, implementations MUST still
validate EAP server certificates in all situations other than
provisioning. Where the provisioning method under the eap.arpa.
domain defines that provisioning happen via another protocol such as
with HTTPS, the EAP peer MAY skip validating the EAP server
certificate.
Whether or not the server certificate is ignored, the peer MUST treat
the local network as untrusted. [RFC8952], Section 6 has more
discussion on this topic.
The ability to not validate the EAP server certificates relaxes the
requirements of [RFC5216], Section 5.3 which requires that the server
certificate is always validated. For the provisioning case, it is
acceptable in some cases to not validate the EAP server certificate,
but only so long as there are other means to authenticate the data
which is being provisioned.
DeKok Expires 8 March 2026 [Page 14]
Internet-Draft eap.arpa September 2025
However, since the device likely is configured with web CAs [CAB]
otherwise, the captive portal would also be unauthenticated,
provisioning methods could use those CAs within an EAP method in
order to allow the peer to authenticate the EAP server. Further
discussion of this topic is better suited for the specification(s)
which define a particular provisioning method. This issue is not
discussed further here, other than to say that it is technically
possible.
4.2. EAP-TLS
This document defines an NAI "portal@tls.eap.arpa", which allows EAP
peers to use unauthenticated EAP-TLS. The purpose of the identifier
is to allow EAP peers to signal EAP servers that they wish to obtain
a "captive portal" style network access.
This identifier signals the EAP server that the peer wishes to obtain
"peer unauthenticated access" as per [RFC5216], Section 2.1.1 and
[RFC9190]. Note that peer unauthenticated access MUST provide for
authentication of the EAP server, such as with a server certificate.
Using TLS-PSK with a well-known PSK value is generally not
appropriate, as it would not provide server authentication.
An EAP server which agrees to authenticate this request MUST ensure
that the device is placed into a captive portal with limited network
access as discussed above in Section 3.4.2.
This method is an improvement over existing captive portals, which
are typically completely unsecured and unauthenticated. Using peer
unauthenticated TLS for network access ensures that the EAP server is
proven to be authentic. The use of 802.1X ensures that the link
between the EAP peer and EAP authenticator (e.g. access point) is
also secured.
Further details of the captive portal architecture can be found in
[RFC8952]. The captive portal can advertise support for the
eap.arpa. domain via an 802.11u realm.
4.3. EAP-NOOB
It is RECOMMENDED that server implementations of Nimble out-of-band
authentication for EAP (EAP-NOOB) accept both identities "noob@eap-
noob.arpa" and "@noob.eap.arpa" as synonyms.
It is RECOMMENDED that EAP-NOOB peers use "@noob.eap.arpa" first, and
if that does not succeed, use "noob@eap-noob.arpa".
DeKok Expires 8 March 2026 [Page 15]
Internet-Draft eap.arpa September 2025
5. IANA Considerations
A number of IANA actions are required. There are two registry
updates in order to define the eap.arpa. domain. A new registry is
created. The "noob@eap-noob.arpa" registry entry is deprecated.
5.1. .arpa updates
There are two updates to the ".arpa" registry.
IANA is also instructed to refuse further allocation requests which
are directly within the ".arpa" registry for any functionality
related to the EAP protocol. Instead, allocations related to EAP are
to be made within the new "EAP Provisioning Identifiers" registry.
5.1.1. Deprecating eap-noob.arpa
IANA is instructed to update the "eap-noob.arpa" entry as follows.
The USAGE field is updated to prefix the text with the word
DEPRECATED.
The REFERENCE field is updated to add a reference to THIS-DOCUMENT.
5.1.2. Defining the eap.arpa. Domain
IANA is instructed to update the ".ARPA Zone Management" registry
[ARPAREG] with the following entry:
DOMAIN
eap.arpa
USAGE
For provisioning within the Extensible Authentication Protocol
framework.
REFERENCE
THIS-DOCUMENT
IANA is instructed to update the "Special-Use Domain Names" registry
as follows:
NAME
eap.arpa.
DeKok Expires 8 March 2026 [Page 16]
Internet-Draft eap.arpa September 2025
REFERENCE
THIS-DOCUMENT
5.1.2.1. Domain Name Reservation Considerations
This section answers the questions which are required by Section 5 of
[RFC6761]. At a high level, these new domain names are used in
certain situations in EAP. The domain names are never seen by users,
and they do not appear in any networking protocol other than EAP.
1. Users: User are not expected to recognize these names as special
or use them differently from other domain names. The use of
these names in EAP is invisible to end users.
2. Application Software: EAP servers and clients are expected to
make their software recognize these names as special and treat
them differently. This document discusses that behavior. EAP
peers should recognize these names as special, and should refuse
to allow users to enter them in any interface. EAP servers and
RADIUS servers should recognize the eap.arpa. domain as special,
and refuse to do dynamic discovery ([RFC7585]) for it.
3. Name Resolution APIs and Libraries: Writers of these APIs and
libraries are not expected to recognize these names or treat them
differently.
4. Caching DNS Servers: Writers of caching DNS servers are not
expected to recognize these names or treat them differently.
5. Authoritative DNS Servers: Writers of authoritative DNS servers
are not expected to recognize these names or treat them
differently.
6. DNS Server Operators: These domain names have minimal impact on
DNS server operators. They should never be used in DNS, or in
any networking protocol outside of EAP.
Some DNS servers may receive lookups for this domain, if EAP or
RADIUS servers are configured to do dynamic discovery for realms
as defined in [RFC7585], and where those servers are not updated
to ignore the ".arpa" domain. When queried for the eap.arpa.
domain, DNS servers SHOULD return an NXDOMAIN error.
If they try to configure their authoritative DNS as authoritative
for this reserved name, compliant name servers do not need to do
anything special. They can accept the domain or reject it.
Either behavior will have no impact on this specification.
DeKok Expires 8 March 2026 [Page 17]
Internet-Draft eap.arpa September 2025
7. DNS Registries/Registrars: DNS Registries/Registrars should deny
requests to register this reserved domain name.
5.2. EAP Provisioning Identifiers Registry
IANA is instructed to add the following new registry to the
"Extensible Authentication Protocol (EAP) Registry" group.
Assignments in this registry are done via "Expert Review" as
described in [RFC8126] Section 4.5. Guidelines for experts is
provided in Section 5.3.
The contents of the registry are as follows.
Title
EAP Provisioning Identifiers
Registration Procedure(s)
Expert review
Reference
THIS-DOCUMENT
Registry
NAI
The Network Access Identifier in [RFC7542] format.
Method Type
The EAP method name, taken from the "Description" field of the
EAP "Method Types" registry.
Reference
Reference where this identifier was defined.
5.2.1. Initial Values
The following table gives the initial values for this table.
DeKok Expires 8 March 2026 [Page 18]
Internet-Draft eap.arpa September 2025
+=====================+=============+=============================+
| NAI | Method-Type | Reference |
+=====================+=============+=============================+
| @noob.eap.arpa | EAP-NOOB | [RFC9140] and THIS-DOCUMENT |
+---------------------+-------------+-----------------------------+
| portal@tls.eap.arpa | EAP-TLS | [RFC9190] and THIS-DOCUMENT |
+---------------------+-------------+-----------------------------+
Table 1
5.3. Guidelines for Designated Experts
The following text gives guidelines for Designated Experts who review
allocation requests for this registry.
5.3.1. NAIs
The intent is for the NAI to describe both the EAP Method Type, and
the purpose of the provisining method. A descriptive format allows
administrators who are unfamiliar with a particular NAI to make
reasonable deductions about the provisioning method being requested.
For example, with an EAP Method Type "name", and a purpose "action",
the NAI SHOULD be of the form "action@name.eap.arpa".
The NAI MUST satisfy the requirements of the [RFC7542], Section 2.2
format. The utf8-username portion MAY be empty. The utf8-username
portion MUST NOT be "anonymous". The NAI MUST be a subdomain within
the eap.arpa realm. NAIs with any "v." subdomain MUST NOT be
registered, in order to preserve the functionality of that subdomain.
NAIs in the registry MUST NOT contain more than one subdomain. NAIs
with a leading "v." subdomain MUST NOT be registered. That subdomain
is reserved for vendor and SDO extensions.
The subdomain of the NAI field should correspond to the EAP Method
Type name. Care should be taken so that the domain name conventions
specified in [STD13] are followed.
The NAIs in this registry are case-insensitive. While [RFC7542]
notes that similar identifiers of different case can be considered to
be different, for simplicity this registry requires that all entries
MUST be lowercase.
Identifiers MUST be unique when compared in a case-insensitive
fashion. While [RFC7542] notes that similar identifiers of different
case can be considered to be different, this registry is made simpler
by requiring case-insensitivity.
DeKok Expires 8 March 2026 [Page 19]
Internet-Draft eap.arpa September 2025
Entries in the registry should be short. NAIs defined here will
generally be sent in a RADIUS packet in the User-Name attribute
([RFC2865] Section 5.1). That specification recommends that
implementations should support User-Names of at least 63 octets. NAI
length considerations are further discussed in [RFC7542] Section 2.3,
and any allocations in this registry needs to take those limitations
into consideration.
Implementations are likely to support a total NAI length of 63
octets. Lengths between 63 and 253 octets may work. Lengths of 254
octets or more will not work with RADIUS [RFC2865].
5.4. Method Type
Values in "Method Type" field of this registry MUST be taken from the
IANA EAP Method Types registry or else it MUST be an Expanded Type
which usually indicates a vendor specific EAP method.
The EAP Method Type MUST provide an MSK and EMSK as defined in
[RFC3748]. Failure to provide these keys means that the method will
not be usable within an authentication framework which requires those
methods, such as with IEEE 802.1X.
5.5. Designated Experts
The Designated Expert will post a request to the EMU WG mailing list
(or a successor designated by the Area Director) for comment and
review, including an Internet-Draft or reference to external
specification. Before a period of 30 days has passed, the Designated
Expert will either approve or deny the registration request and
publish a notice of the decision to the EAP Method Update (EMU) WG
mailing list or its successor, as well as informing IANA. A denial
notice must be justified by an explanation, and in the cases where it
is possible, concrete suggestions on how the request can be modified
so as to become acceptable should be provided.
5.6. Organization Self Assignment
This registry allows organizations to request allocations from this
registry, but explicit allocations are not always required. Any NAI
defined in this registry also implicitly defines a subdomain "v.".
Organizations can self-allocate in this space, under the "v."
subdomain, e.g. "local@example.com.v.tls.eap.arpa".
The purpose of self-assigned realms is for testing, and for future
expansion. There are currently no use-cases being envisioned for
these realms, but we do not wish to forbid future expansion.
DeKok Expires 8 March 2026 [Page 20]
Internet-Draft eap.arpa September 2025
An organization which has registered a Fully Qualified Domain Name
(FQDN) within the DNS can use that name within the "v." subdomain.
As DNS registrations can change over time, an organization may stop
using a domain at some point. This change is reflected in the DNS,
but is unlikely to be reflected in shipped products which use a self-
assigned realm. There is no solution to this problem, other than
suggesting that organizations using self-assigned realms do not allow
their DNS registrations to expire.
It is therefore RECOMMENDED that organizations avoid the use of self-
assigned realms. Organizations MAY use self-assigned realms only
when no other alternative exists, and when the organization expects
to maintain operation for at least the lifetime of the devices which
use these realms.
6. Privacy Considerations
The EAP Identity field is generally publicly visible to parties who
can observe the EAP traffic. As the names given here are in a public
specification, there is no privacy implication to exposing those
names within EAP. The entire goal of this specification is in fact
to make those names public, so that unknown (and private) parties can
publicly (and anonymously) declare what kind of network access they
desire.
However, there are many additional privacy concerns around this
specification. Most EAP traffic is sent over RADIUS [RFC2865]. The
RADIUS Access-Request packets typically contain large amounts of
information such as MAC addresses, device location, etc.
This specification does not change RADIUS or EAP, and as such does
not change which information is publicly available, or is kept
private. Those issues are dealt with in other specifications, such
as [I-D.ietf-radext-deprecating-radius].
However, this specification can increase privacy by allowing devices
to anonymously obtain network access, and then securely obtain
credentials.
The NAIs used here are contained in a public registry, and therefore
do not have to follow the username privacy recommendations of
[RFC7542], Section 2.4. However, there may be other personally
identifying information contained in EAP or AAA packets. This
situation is no different from normal EAP authentication, and thus
has no additional positive or negative implications for privacy.
DeKok Expires 8 March 2026 [Page 21]
Internet-Draft eap.arpa September 2025
7. Security Considerations
This specification defines a framework which permits unknown,
anonymous, and unauthenticated devices to request and to obtain
network access. As such, it is critical that network operators
provide limited access to those devices.
Future specifications which define an NAI within this registry,
should give detailed descriptions of what kind of network access is
to be provided.
7.1. On-Path Attackers and Impersonation
In most EAP use-cases, the server identity is validated (usually
through a certificate), or the EAP method allows the TLS tunnel to be
cryptographically bound to the inner application data. For the
methods outlined here, the use of public credentials, and/or skipping
server validation allows "on-path" attacks to succeed where they
would normally fail
EAP peers and servers MUST assume that all data sent over an EAP
session is visible to attackers, and can be modified by them.
The methods defined here MUST only be used to bootstrap initial
network access. Once a device has been provisioned, it gains network
access via the provisioned credentials, and any network access
policies can be applied.
7.2. Provisioning is Unauthenticated
This specification allows for unauthenticated EAP peers to obtain
network access, however limited. As with any unauthenticated
process, it can be abused. Implementations should take care to limit
the use of the provisioning network.
Section 3.4.2 describes a number of methods which can be used to
secure the provisioning network. In summary:
* allow only traffic which is needed for the current provisioning
method. All other traffic should be blocked. Most notable, DNS
has been used to exfiltrate network traffic, so DNS recursive
resolvers SHOULD NOT be made available on the provisioning
network.
* limit the services available on the provisioning network to only
those services which are needed for provisioning.
DeKok Expires 8 March 2026 [Page 22]
Internet-Draft eap.arpa September 2025
* limit the number of devices which can access the provisioning
network at the same time.
* for any one device, rate limit its access the provisioning
network.
* for a device which has accessed the provisioning network, limit
the total amount of time which it is allowed to remain on the
network
* for a device which has accessed the provisioning network, limit
the total amount of data which it is allowed to transfer through
the network.
8. Acknowledgements
Mohit Sethi provided valuable insight that using subdomains was
better and more informative than the original method, which used only
the utf8-username portion of the NAI.
The document was further improved with reviews from Ignes Robles and
Ben Kaduk.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Levkowetz, Ed., "Extensible Authentication Protocol
(EAP)", RFC 3748, DOI 10.17487/RFC3748, June 2004,
<https://www.rfc-editor.org/rfc/rfc3748>.
[RFC5216] Simon, D., Aboba, B., and R. Hurst, "The EAP-TLS
Authentication Protocol", RFC 5216, DOI 10.17487/RFC5216,
March 2008, <https://www.rfc-editor.org/rfc/rfc5216>.
[RFC7542] DeKok, A., "The Network Access Identifier", RFC 7542,
DOI 10.17487/RFC7542, May 2015,
<https://www.rfc-editor.org/rfc/rfc7542>.
DeKok Expires 8 March 2026 [Page 23]
Internet-Draft eap.arpa September 2025
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/rfc/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC9140] Aura, T., Sethi, M., and A. Peltonen, "Nimble Out-of-Band
Authentication for EAP (EAP-NOOB)", RFC 9140,
DOI 10.17487/RFC9140, December 2021,
<https://www.rfc-editor.org/rfc/rfc9140>.
[STD13] Internet Standard 13,
<https://www.rfc-editor.org/info/std13>.
At the time of writing, this STD comprises the following:
Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>.
Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <https://www.rfc-editor.org/info/rfc1035>.
9.2. Informative References
[ARPAREG] IANA, ".ARPA Zone Management", n.d.,
<https://www.iana.org/domains/arpa>.
[CAB] Forum, C., "CA/Browser Forum", n.d.,
<https://cabforum.org/>.
[EAPREG] IANA, "Extensible Authentication Protocol (EAP) Registry",
n.d., <https://www.iana.org/assignments/eap-numbers/eap-
numbers.xhtml>.
[HOTSPOT] Alliance, W.-F., "Passpoint", n.d.,
<https://www.wi-fi.org/discover-wi-fi/passpoint>.
[I-D.ietf-radext-deprecating-radius]
DeKok, A., "Deprecating Insecure Practices in RADIUS",
Work in Progress, Internet-Draft, draft-ietf-radext-
deprecating-radius-07, 27 August 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-radext-
deprecating-radius-07>.
DeKok Expires 8 March 2026 [Page 24]
Internet-Draft eap.arpa September 2025
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<https://www.rfc-editor.org/rfc/rfc2865>.
[RFC5931] Harkins, D. and G. Zorn, "Extensible Authentication
Protocol (EAP) Authentication Using Only a Password",
RFC 5931, DOI 10.17487/RFC5931, August 2010,
<https://www.rfc-editor.org/rfc/rfc5931>.
[RFC6761] Cheshire, S. and M. Krochmal, "Special-Use Domain Names",
RFC 6761, DOI 10.17487/RFC6761, February 2013,
<https://www.rfc-editor.org/rfc/rfc6761>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/rfc/rfc7030>.
[RFC7170] Zhou, H., Cam-Winget, N., Salowey, J., and S. Hanna,
"Tunnel Extensible Authentication Protocol (TEAP) Version
1", RFC 7170, DOI 10.17487/RFC7170, May 2014,
<https://www.rfc-editor.org/rfc/rfc7170>.
[RFC7585] Winter, S. and M. McCauley, "Dynamic Peer Discovery for
RADIUS/TLS and RADIUS/DTLS Based on the Network Access
Identifier (NAI)", RFC 7585, DOI 10.17487/RFC7585, October
2015, <https://www.rfc-editor.org/rfc/rfc7585>.
[RFC8952] Larose, K., Dolson, D., and H. Liu, "Captive Portal
Architecture", RFC 8952, DOI 10.17487/RFC8952, November
2020, <https://www.rfc-editor.org/rfc/rfc8952>.
[RFC9190] Preuß Mattsson, J. and M. Sethi, "EAP-TLS 1.3: Using the
Extensible Authentication Protocol with TLS 1.3",
RFC 9190, DOI 10.17487/RFC9190, February 2022,
<https://www.rfc-editor.org/rfc/rfc9190>.
[RFC9810] Brockhaus, H., von Oheimb, D., Ounsworth, M., and J. Gray,
"Internet X.509 Public Key Infrastructure -- Certificate
Management Protocol (CMP)", RFC 9810,
DOI 10.17487/RFC9810, July 2025,
<https://www.rfc-editor.org/rfc/rfc9810>.
Author's Address
Alan DeKok
InkBridge Networks
DeKok Expires 8 March 2026 [Page 25]
Internet-Draft eap.arpa September 2025
Email: alan.dekok@inkbridge.io
DeKok Expires 8 March 2026 [Page 26]