Media Access Control (MAC) Addresses in X.509 Certificates
draft-ietf-lamps-macaddress-on-07

[Ballot comment]
Thanks to the authors and the WG for their work on this document.

I have a couple of comments about the IANA considerations:

1) Please identify the registry group under which those registries are located. In this case, I believe it is "Structure of Management Information (SMI) Numbers (MIB Module Registrations)" ?

2) id-mod-mac-address-other-name-2025 should be id-mod-mac-address-other-name-2026 ... based on the pattern that I observe in that registry?

[Ballot comment]
Thanks for the work done in this document, and knowing the authors, no wonder that both 48-bit and 64-bit MAC addresses are supported.

Thanks also to Jacqueline McCall for the IoT-directorate review and the follow-up by the authors.

Final thanks to David Lou for the INT-directorate review.

[Ballot comment]
# IESG review of draft-ietf-lamps-macaddress-on-06

CC @MikeBishop

## Comments

### Section 3.3, paragraph 4

Would this be a case warranting IAN usage?

### Section 3.4.1, paragraph 10

Being somewhat pedantic, various invalid lengths of n and c could pass
the algorithm in the text and fail the code or vice versa. You probably want to
add either an assumption that the inputs are valid or explicit checks that the
inputs are one of the two valid lengths.

### Section 4, paragraph 2

The mechanics of this make me nervous. It seems like it would be very
easy to claim control of a MAC that is actually on the router between the CA and
an attacker.

### Inclusive language

Found terminology that should be reviewed for inclusivity; see
https://www.rfc-editor.org/part2/#inclusive_language for background and more
guidance:

* Term `natively`; alternatives might be `built-in`, `fundamental`,
  `ingrained`, `intrinsic`, `original`

## Nits

All comments below are about very minor potential issues that you may choose to
address in some way - or ignore - as you see fit. Some were flagged by
automated tools (via https://github.com/larseggert/ietf-reviewtool), so there
will likely be some false positives. There is no need to let me know what you
did with these suggestions.

### Typos

#### Section 3, paragraph 1
```
-    all refer to a GeneraName.otherName field included in a SAN or IAN.
+    all refer to a GeneralName.otherName field included in a SAN or IAN.
+                        +
```

### Section 3, paragraph 1

You're inconsistent in the document whether the separator here is '-'
(U+002D, "hyphen-minus") or '‑' (U+2011, "non-breaking hyphen"). I'd assume
U+002D was the intent and this is just copy-paste or text editor vagaries.

(There are many other instances of U+2011 throughout the document, but the
identifier is the one with actual interop implications.)

### Grammar/style

#### Section 2, paragraph 1
```
ey an EUI-48 as an OCTET STRING comprising of 6 octets, or an EUI-64 as an OC
                                ^^^^^^^^^^^^^
```
Did you mean "comprising" or "comprised of"?

#### Section 2, paragraph 1
```
or an EUI-64 as an OCTET STRING comprising of 8 octets. Constraints on EUI-4
                                ^^^^^^^^^^^^^
```
Did you mean "comprising" or "comprised of"?

#### Section 3, paragraph 1
```
the bit pattern. The following sub-sections describe how to encode EUI-48 an
                                ^^^^^^^^^^^^
```
This word is normally spelled as one.

#### Section 3.1, paragraph 2
```
, a constraint that specifies that the the acceptable names must all be withi
                                  ^^^^^^^
```
Possible typo: you repeated a word.

#### Section 3.3, paragraph 1
```
f type id-on-MACAddress. In the pseudo-code below, 'mask' is shorthand for t
                                ^^^^^^^^^^^
```
This word is normally spelled as one.

#### Section 3.4.1, paragraph 7
```
by any universal/unicast address with a OUI of 00-00-5E -i.e., it will also m
                                      ^
```
Use "an" instead of "a" if the following word starts with a vowel sound, e.g.
"an article", "an hour".

#### Section 3.4.2, paragraph 1
```
bits within the OUI of 00-00-0e. If 'constraint child2 = '00005E005000 FFFF
                                    ^
```
Unpaired symbol: "'" seems to be missing.

[Ballot comment]
Section 4, paragraph 0
>    The binding of a MAC address to a certificate is only as strong as
>    the CA's validation process.  CAs MUST verify that the subscriber
>    legitimately controls or owns the asserted MAC address.

Since you mention the binding of the MAC address to a certificate, this
section should include a note on MAC spoofing, e.g., that the trust
model depends on the CA and the deployment controls, and that MAC
addresses can be spoofed at L2. Having that here makes the threat
model clearer in my mind.

Section 5, paragraph 1
>        +=========+====================================+===============+
>        | Decimal | Description                        | References    |
>        +=========+====================================+===============+
>        | TBD0    | id-mod-mac-address-other-name-2025 | This document |
>        +---------+------------------------------------+---------------+

Not sure of the significance of the number 2025, but if this has anything
to do with the year 2025, maybe it can be updated to 2026.

No reference entries found for these items, which were mentioned in the text:
[draft-housley-lamps-macaddress-on].

Possible DOWNREF from this Standards Track doc to [X680]. If so, the IESG needs
to approve it.

Found terminology that should be reviewed for inclusivity; see
https://www.rfc-editor.org/part2/#inclusive_language for background and more
guidance:

* Term "natively"; alternatives might be "built-in", "fundamental",
  "ingrained", "intrinsic", "original"

-------------------------------------------------------------------------------
NIT
-------------------------------------------------------------------------------

All comments below are about very minor potential issues that you may choose to
address in some way - or ignore - as you see fit. Some were flagged by
automated tools (via https://github.com/larseggert/ietf-reviewtool), so there
will likely be some false positives. There is no need to let me know what you
did with these suggestions.

Section 3, paragraph 0
>    In this document "otherName", "OtherName" and "GeneralName.otherName"
>    all refer to a GeneraName.otherName field included in a SAN or IAN.
>    The new name form is identified by the object identifier (OID)
>    id-on-MACAddress (TBD1) and declared below using the OTHER-NAME class
>    declaration syntax.  The name form has variants to convey an EUI-48
>    as an OCTET STRING comprising of 6 octets, or an EUI-64 as an OCTET
>    STRING comprising of 8 octets.  Constraints on EUI-48 and EUI-64
>    values are conveyed as OCTET STRINGs whose lengths are twice the
>    octet length of the identifiers.  The first set of N octets (where N
>    is the length of the address octets) define the bit pattern of the
>    constraint that the address must match, and the second set of N
>    octets defines the bit mask that defines the set of significant bits
>    in the bit pattern.

s/GeneraName/GeneralName/

Section 3.2, paragraph 4
>    For example, a constraint that specifies that the the acceptable
>    names must all be within an Organizationally Unique Identifier (OUI)
>    of '00-00-5e' for an EUI-48 address, would have a value part of
>    '00005E000000'H, a mask part of 'FFFFFFFF000000'H and would be
>    encoded as OCTET STRING '00005E000000FFFFFF000000'H.

s/the the/the/

Section 3.4.2, paragraph 0
>    This section describes the Path Validation Processing specific to
>    OtherName.MACAddress constraints.  N.B., It is possible to build
>    hierarchies of NCEs for OtherName.MACAddress's that prohibit all
>    names, even if that was not intended.  For example, say that the
>    level 1 NCE contained only a "permitted_subtrees" of only
>    (OtherName.MACAddress) global/unicast EUI-48, and the level 2 NCE
>    contained only a "permitted_subtress" of "any address" (i.e. the
>    initial constraint set).  This would result in an empty
>    permitted_subtrees set as an "any address" constraint is not
>    contained within a "global/unicast" constraint.  The worked example
>    is left to the reader.

s/permitted_subtress/permitted_subtrees/

Section 3.4.2.2, paragraph 5
> // rst => one of the requested subtrees (from the cert)
> // pst -> one of the current permitted subtrees
> foreach ( constraint rst in tempRequestedSubtrees) {
>    foreach ( constraint pst in prevSubtrees) {
>          if (childIsSubsetofParent (rst,
>                                    pst) {
>                tempPermittedSubtrees += requestedSubtree;
>                break;
>          }
>      }
>  }

s/childIsSubsetofParent/childIsSubsetOfParent/

Section 3.4.2.3, paragraph 4
>    // note that the ordering of the loop here differs
>    // from the 'intersection' operation.
>    foreach (constraint rExcl in tempRequestedSubtrees) {
>      boolean matches = false;
>      foreach (constraint est in tempExcludedSubtrees) {
>          // If I find a constraint in the current excluded
>          // constraints that 'covers' the requested subtree,
>          // I do not need to add the requested subtree
>          // to the set of excluded subtrees.
>          if (childIsSubsetParent (rExcl, est)) {
>            matches = true;
>            break;
>          }
>      }
 
s/childIsSubsetParent/childIsSubsetOfParent/

Section 6, paragraph 0
>    This Appendix contains the ASN.1 Module for the MAC Address; it
>    follows the conventions established by [RFC5912].

s/This Appendix/This Section/

These URLs in the document did not return content:

* https://standards.ieee.org/wp-content/uploads/import/documents/tutorials/eui.pdf

Section 1, paragraph 3
> ey an EUI-48 as an OCTET STRING comprising of 6 octets, or an EUI-64 as an OC
>                                ^^^^^^^^^^^^^
Did you mean "comprising" or "consisting of"?

Section 2, paragraph 1
> or an EUI-64 as an OCTET STRING comprising of 8 octets. Constraints on EUI-4
>                                ^^^^^^^^^^^^^
Did you mean "comprising" or "consisting of"?

Section 2, paragraph 2
> Name/GeneralName/ The following sub-sections describe how to encode EUI-48 an
>                                ^^^^^^^^^^^^
This word is normally spelled as one.

Section 3.1, paragraph 2
> , a constraint that specifies that the the acceptable names must all be withi
>                                    ^^^^^^^
Possible typo: you repeated a word.

Section 3.2, paragraph 1
> ING '00005E000000FFFFFF000000'H. s/the the/the/ The bit patterns encoded in
>                                    ^^^^^^^
Possible typo: you repeated a word.

Section 3.2, paragraph 4
> are the same layer-2 interface. A relying party that matches a presented MAC
>                                  ^^^^^^^
The verb "rely" requires the preposition "on" (or "upon").

Section 3.2, paragraph 8
> f type id-on-MACAddress. In the pseudo-code below, 'mask' is shorthand for t
>                                ^^^^^^^^^^^
This word is normally spelled as one.

Section 3.4.1, paragraph 5
> by any universal/unicast address with a OUI of 00-00-5E -i.e., it will also m
>                                      ^
Use "an" instead of "a" if the following word starts with a vowel sound, e.g.
"an article", "an hour".

[Ballot comment]
Thank you to Vijay Gurbani for the GENART review.

** Section 4
  CAs MUST verify that the subscriber
  legitimately controls or owns the asserted MAC address.

Consider if this is the appropriate framing – can you “own” a MAC address?  Why “subscriber” -- is the assignment of OUI a subscription service (don’t think so)?  Is subscriber here assuming a particular deployment model?  Section 7.3 uses similar language.

[Ballot comment]
Hi Russ, Corey, Joe, Tomofumi, and Mike,

Thank you for the effort put into this specification.

Please find below some few comments:

# I was wondering whether there is any operational impact that need to be highligted for devices that agressively rotate their MAC addresses (e.g., guards to issue too short-lived certificates)?

# For this one: 

CURRENT:
  The same MAC
  address MUST NOT be included in certificates issued to different
  devices, unless different devices share the same layer-2 interface.

## I guess this is reasoning for active certificates?

## How the issuer knows that these devices share the same L2 interface? What does that mean actually?

I flagged some few nits that I will send in a seprate PR to the authors.

Cheers,
Med

[Ballot comment]
# Internet AD comments for draft-ietf-lamps-macaddress-on-06
CC @ekline

* comment syntax:
  - https://github.com/mnot/ietf-comments/blob/main/format.md

* "Handling Ballot Positions":
  - https://ietf.org/about/groups/iesg/statements/handling-ballot-positions/

## Comments

### S3.4.1

* I saw there's an earlier requirement on CAs not to sign malformed
  NCE instances (S3.2) but might there be an addition check here, perhaps:

  "4.1 Perform a bitwise AND operation with the value bit pattern from
  Step 3 and mask bit pattern from Step 4. If the resulting value does
  not equal the value bit pattern the NCE is invalid."

  or something? (or perhaps I've misunderstood)

## Nits

### S3

* "GeneraName.otherName" ->
  "GeneralName.otherName" I expect

* "comprising of" -> "comprising", I believe

IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-lamps-macaddress-on-05. If any part of this review is inaccurate, please let us know.

IANA understands that, upon approval of this document, there are two actions which we must complete.

First, in the SMI Security for PKIX Module Identifier registry in the Structure of Management Information (SMI) Numbers (MIB Module Registrations) registry group located at:

https://www.iana.org/assignments/smi-numbers/

a single new registration is to be made as follows:

Decimal: [ TBD-at-Registration ]
Description: id-mod-mac-address-other-name-2025
Reference: [ RFC-to-be ]

As this document requests a registration in an Expert Review or Specification Required (see RFC 8126) registry, we will initiate the required Expert Review via a separate request. This review must be completed before the document's IANA state can be changed to "IANA OK."

Second, in the SMI Security for PKIX Other Name Forms also on the Structure of Management Information (SMI) Numbers (MIB Module Registrations) registry group located at:

https://www.iana.org/assignments/smi-numbers/

a single, new registration is to be made as follows:

Decimal: [ TBD-at-Registration ]
Description: id-on-MACAddress
Reference: [ RFC-to-be ]

As this also requests a registration in an Expert Review or Specification Required (see RFC 8126) registry, we will initiate the required Expert Review via a separate request. This review must be completed before the document's IANA state can be changed to "IANA OK."

We understand that these are the only actions required to be completed upon approval of this document.

NOTE: The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

For definitions of IANA review states, please see:

https://datatracker.ietf.org/help/state/draft/iana-review

Thank you,

David Dong
IANA Services Sr. Specialist

The following Last Call announcement was sent out (ends 2026-02-13):

From: The IESG
To: IETF-Announce
CC: debcooley1@gmail.com, draft-ietf-lamps-macaddress-on@ietf.org, lamps-chairs@ietf.org, spasm@ietf.org, tim.hollebeek@digicert.com
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Media Access Control (MAC) Addresses in X.509 Certificates) to Proposed Standard


The IESG has received a request from the Limited Additional Mechanisms for
PKIX and SMIME WG (lamps) to consider the following document: - 'Media Access
Control (MAC) Addresses in X.509 Certificates'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
last-call@ietf.org mailing lists by 2026-02-13. Exceptionally, comments may
be sent to iesg@ietf.org instead. In either case, please retain the beginning
of the Subject line to allow automated sorting.

Abstract


  This document defines a new GeneralName.otherName for inclusion in
  the X.509 Subject Alternative Name (SAN) and Issuer Alternative Name
  (IAN) extensions to carry an IEEE Media Access Control (MAC) address.
  The new name form makes it possible to bind a layer-2 interface
  identifier to a public key certificate.  Additionally, this document
  defines how constraints on this name form can be encoded and
  processed in the X.509 Name Constraints extension (NCE).




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-lamps-macaddress-on/



No IPR declarations have been submitted directly on this I-D.

# Document Shepherd Write-Up for Group Documents

*This version is dated 4 July 2022.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up to give helpful context to Last Call
and Internet Engineering Steering Group ([IESG][1]) reviewers, and your
diligence in completing it is appreciated. The full role of the shepherd is
further described in [RFC 4858][2]. You will need the cooperation of the authors
and editors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

The draft is straightforward and there was broad agreement during the LAMPS
meeting at IETF 124 that it was a good idea. The WG consensus represents broad
agreement rather than just a few individuals.

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

No. There was no controversy about particular points and no rough consensus
decisions.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
  so, please summarize the areas of conflict in separate email messages to the
  responsible Area Director. (It should be in a separate email because this
  questionnaire is publicly available.)

No one has threatened an appeal or indicated discontent.

4. For protocol documents, are there existing implementations of the contents of
  the document? Have a significant number of potential implementers indicated
  plans to implement? Are any existing implementations reported somewhere,
  either in the document itself (as [RFC 7942][3] recommends) or elsewhere
  (where)?

One of the authors (Corey Bonnell) works for DigiCert, which plans to implement
this specification.

## Additional Reviews

5. Do the contents of this document closely interact with technologies in other
  IETF working groups or external organizations, and would it therefore benefit
  from their review? Have those reviews occurred? If yes, describe which
  reviews took place.

This document interacts with IEEE 802 for MAC address format definitions
(EUI-48/EUI-64) and RFC 5280 (X.509 PKI) for certificate extensions and Name
Constraints. The document does not require review from other IETF WGs, as it is
a straightforward extension to existing PKIX mechanisms. The IEEE MAC address
formats are well-established standards. No additional external reviews are
necessary.

6. Describe how the document meets any required formal expert review criteria,
  such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

This document does not define any MIBs, YANG modules, media types, or URI
schemes. No formal expert reviews of these types are required.

7. If the document contains a YANG module, has the final version of the module
  been checked with any of the [recommended validation tools][4] for syntax and
  formatting validation? If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time? Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

This document does not contain a YANG module. This question is not applicable.

8. Describe reviews and automated checks performed to validate sections of the
  final version of the document written in a formal language, such as XML code,
  BNF rules, MIB definitions, CBOR's CDDL, etc.

The document contains an ASN.1 module in Section 6. The module has been
validated with an ASN.1 compiler.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
  document is needed, clearly written, complete, correctly designed, and ready
  to be handed off to the responsible Area Director?

In the opinion of the shepherd, the document is clear, complete, correctly
designed, and no security concerns are noted. The document is ready to be
handed off to the responsible Area Director.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    reviews?

The document falls under the Security Area. The Security Area checklist was
reviewed; no concerns noted. The document includes a Security Considerations
section addressing CA validation, dynamic MAC assignment concerns, and scope
limitations, as well as a Privacy Considerations subsection addressing device
tracking concerns.

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?

Proposed Standard. The document defines a new otherName form for X.509
certificates to carry MAC addresses, extending the framework defined in
RFC 5280. It uses normative language (MUST/SHOULD) to ensure interoperability
and specifies precise encoding rules and Name Constraints processing
algorithms. Proposed Standard is appropriate as this defines protocol elements
that require consistent implementation across deployments. The Datatracker
correctly reflects the intended status. Note that the "Intended status:
Informational" shown in the current draft text is incorrect and will need to
be corrected to "Proposed Standard" in a future revision.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.

The authors have been reminded of their IPR disclosure obligations. Authors
have responded affirmatively by private email confirming awareness of
IPR obligations.

To the best of my knowledge, no IPR disclosures have been filed or are needed
for this document.

13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.

The document has four authors listed on the front page: Russ Housley (Vigil
Security), Corey Bonnell (DigiCert), Joe Mandel (AKAYLA), and Tomofumi Okubo
(Penguin Securities). This is within the five-author limit and does not require
justification. Authors have confirmed their willingness to be listed by
private email.

14. Document any remaining I-D nits in this document. Simply running the [idnits
    tool][8] is not enough; please review the ["Content Guidelines" on
    authors.ietf.org][15]. (Also note that the current idnits tool generates
    some incorrect warnings; a rewrite is underway.)

The idnits tool (version 2.17.1) reports the following issues:

Errors: 3 instances of lines longer than 72 characters (longest is 13
characters over limit).

Warnings: 9 instances of lines with non-ASCII characters in the document
(en-dash characters in Section 7.3).

Comments: Reference-like text "[0]" on line 488 (this is intentional ASN.1
notation, not a missing reference).

The long lines and non-ASCII en-dash characters will be fixed in a future
revision.

15. Should any informative references be normative or vice-versa? See the [IESG
    Statement on Normative and Informative References][16].

The document has only normative references: RFC 2119 (BCP 14 keywords),
RFC 5280 (X.509 PKI), RFC 5912 (ASN.1 modules for PKIX), and RFC 8174 (BCP 14
clarification). All references appear to be correctly classified.

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?

All normative references (RFC 2119, RFC 5280, RFC 5912, RFC 8174) are freely
available from the RFC Editor. No access issues exist.

17. Are there any normative downward references (see [RFC 3967][9] and [BCP
    97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
    list them.

The document is targeting Proposed Standard status. RFC 5912 is an
Informational RFC being referenced normatively from a Proposed Standard.
However, RFC 5912 is already listed in the DOWNREF registry, so no new downref
approval is required.

18. Are there normative references to documents that are not ready to be
    submitted to the IESG for publication or are otherwise in an unclear state?
    If so, what is the plan for their completion?

No. All normative references are to published RFCs.

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.

No. This document does not update or obsolete any existing RFCs. It defines a
new otherName form that extends the framework defined in RFC 5280.

20. Describe the document shepherd's review of the IANA considerations section,
    especially with regard to its consistency with the body of the document.
    Confirm that all aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).

The IANA Considerations section (Section 5) requests two assignments:

1. SMI Security for PKIX Module Identifier (1.3.6.1.5.5.7.0): TBD0 for
  id-mod-mac-address-other-name-2025. This is used in the ASN.1 module
  definition in Section 6.

2. SMI Security for PKIX Other Name Forms (1.3.6.1.5.5.7.8): TBD1 for
  id-on-MACAddress. This is the OID for the new otherName form, referenced
  throughout Sections 3 and 6.

The registries are correctly identified. No new registries are created. The
assignments are consistent with the body of the document.

21. List any new IANA registries that require Designated Expert Review for
    future allocations. Are the instructions to the Designated Expert clear?
    Please include suggestions of designated experts, if appropriate.

This document does not create any new IANA registries. No Designated Expert is
required.

[1]: https://www.ietf.org/about/groups/iesg/
[2]: https://www.rfc-editor.org/rfc/rfc4858.html
[3]: https://www.rfc-editor.org/rfc/rfc7942.html
[4]: https://wiki.ietf.org/group/ops/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://wiki.ietf.org/group/iesg/ExpertTopics
[7]: https://www.rfc-editor.org/info/bcp79
[8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html
[10]: https://www.rfc-editor.org/info/bcp97
[11]: https://www.rfc-editor.org/rfc/rfc8126.html
[12]: https://www.rfc-editor.org/rfc/rfc2026.html#section-5
[13]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1
[14]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2
[15]: https://authors.ietf.org/en/content-guidelines-overview
[16]: https://www.ietf.org/about/groups/iesg/statements/normative-informative-references/
[17]: https://datatracker.ietf.org/doc/downref/

# Document Shepherd Write-Up for Group Documents

*This version is dated 4 July 2022.*

Thank you for your service as a document shepherd. Among the responsibilities is
answering the questions in this write-up to give helpful context to Last Call
and Internet Engineering Steering Group ([IESG][1]) reviewers, and your
diligence in completing it is appreciated. The full role of the shepherd is
further described in [RFC 4858][2]. You will need the cooperation of the authors
and editors to complete these checks.

Note that some numbered items contain multiple related questions; please be sure
to answer all of them.

## Document History

1. Does the working group (WG) consensus represent the strong concurrence of a
  few individuals, with others being silent, or did it reach broad agreement?

The draft is straightforward and there was broad agreement during the LAMPS
meeting at IETF 124 that it was a good idea. The WG consensus represents broad
agreement rather than just a few individuals.

2. Was there controversy about particular points, or were there decisions where
  the consensus was particularly rough?

No. There was no controversy about particular points and no rough consensus
decisions.

3. Has anyone threatened an appeal or otherwise indicated extreme discontent? If
  so, please summarize the areas of conflict in separate email messages to the
  responsible Area Director. (It should be in a separate email because this
  questionnaire is publicly available.)

No one has threatened an appeal or indicated discontent.

4. For protocol documents, are there existing implementations of the contents of
  the document? Have a significant number of potential implementers indicated
  plans to implement? Are any existing implementations reported somewhere,
  either in the document itself (as [RFC 7942][3] recommends) or elsewhere
  (where)?

One of the authors (Corey Bonnell) works for DigiCert, which plans to implement
this specification.

## Additional Reviews

5. Do the contents of this document closely interact with technologies in other
  IETF working groups or external organizations, and would it therefore benefit
  from their review? Have those reviews occurred? If yes, describe which
  reviews took place.

This document interacts with IEEE 802 for MAC address format definitions
(EUI-48/EUI-64) and RFC 5280 (X.509 PKI) for certificate extensions and Name
Constraints. The document does not require review from other IETF WGs, as it is
a straightforward extension to existing PKIX mechanisms. The IEEE MAC address
formats are well-established standards. No additional external reviews are
necessary.

6. Describe how the document meets any required formal expert review criteria,
  such as the MIB Doctor, YANG Doctor, media type, and URI type reviews.

This document does not define any MIBs, YANG modules, media types, or URI
schemes. No formal expert reviews of these types are required.

7. If the document contains a YANG module, has the final version of the module
  been checked with any of the [recommended validation tools][4] for syntax and
  formatting validation? If there are any resulting errors or warnings, what is
  the justification for not fixing them at this time? Does the YANG module
  comply with the Network Management Datastore Architecture (NMDA) as specified
  in [RFC 8342][5]?

This document does not contain a YANG module. This question is not applicable.

8. Describe reviews and automated checks performed to validate sections of the
  final version of the document written in a formal language, such as XML code,
  BNF rules, MIB definitions, CBOR's CDDL, etc.

The document contains an ASN.1 module in Section 6. The module has been
validated with an ASN.1 compiler.

## Document Shepherd Checks

9. Based on the shepherd's review of the document, is it their opinion that this
  document is needed, clearly written, complete, correctly designed, and ready
  to be handed off to the responsible Area Director?

In the opinion of the shepherd, the document is clear, complete, correctly
designed, and no security concerns are noted. The document is ready to be
handed off to the responsible Area Director.

10. Several IETF Areas have assembled [lists of common issues that their
    reviewers encounter][6]. For which areas have such issues been identified
    and addressed? For which does this still need to happen in subsequent
    reviews?

The document falls under the Security Area. The Security Area checklist was
reviewed; no concerns noted. The document includes a Security Considerations
section addressing CA validation, dynamic MAC assignment concerns, and scope
limitations, as well as a Privacy Considerations subsection addressing device
tracking concerns.

11. What type of RFC publication is being requested on the IETF stream ([Best
    Current Practice][12], [Proposed Standard, Internet Standard][13],
    [Informational, Experimental or Historic][14])? Why is this the proper type
    of RFC? Do all Datatracker state attributes correctly reflect this intent?

Proposed Standard. The document defines a new otherName form for X.509
certificates to carry MAC addresses, extending the framework defined in
RFC 5280. It uses normative language (MUST/SHOULD) to ensure interoperability
and specifies precise encoding rules and Name Constraints processing
algorithms. Proposed Standard is appropriate as this defines protocol elements
that require consistent implementation across deployments. The Datatracker
correctly reflects the intended status. Note that the "Intended status:
Informational" shown in the current draft text is incorrect and will need to
be corrected to "Proposed Standard" in a future revision.

12. Have reasonable efforts been made to remind all authors of the intellectual
    property rights (IPR) disclosure obligations described in [BCP 79][7]? To
    the best of your knowledge, have all required disclosures been filed? If
    not, explain why. If yes, summarize any relevant discussion, including links
    to publicly-available messages when applicable.

The authors have been reminded of their IPR disclosure obligations. Authors
have responded affirmatively by private email confirming awareness of
IPR obligations.

To the best of my knowledge, no IPR disclosures have been filed or are needed
for this document.

13. Has each author, editor, and contributor shown their willingness to be
    listed as such? If the total number of authors and editors on the front page
    is greater than five, please provide a justification.

The document has four authors listed on the front page: Russ Housley (Vigil
Security), Corey Bonnell (DigiCert), Joe Mandel (AKAYLA), and Tomofumi Okubo
(Penguin Securities). This is within the five-author limit and does not require
justification. Authors have confirmed their willingness to be listed by
private email.

14. Document any remaining I-D nits in this document. Simply running the [idnits
    tool][8] is not enough; please review the ["Content Guidelines" on
    authors.ietf.org][15]. (Also note that the current idnits tool generates
    some incorrect warnings; a rewrite is underway.)

The idnits tool (version 2.17.1) reports the following issues:

Errors: 3 instances of lines longer than 72 characters (longest is 13
characters over limit).

Warnings: 9 instances of lines with non-ASCII characters in the document
(en-dash characters in Section 7.3).

Comments: Reference-like text "[0]" on line 488 (this is intentional ASN.1
notation, not a missing reference).

The long lines and non-ASCII en-dash characters will be fixed in a future
revision.

15. Should any informative references be normative or vice-versa? See the [IESG
    Statement on Normative and Informative References][16].

The document has only normative references: RFC 2119 (BCP 14 keywords),
RFC 5280 (X.509 PKI), RFC 5912 (ASN.1 modules for PKIX), and RFC 8174 (BCP 14
clarification). All references appear to be correctly classified.

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?

All normative references (RFC 2119, RFC 5280, RFC 5912, RFC 8174) are freely
available from the RFC Editor. No access issues exist.

17. Are there any normative downward references (see [RFC 3967][9] and [BCP
    97][10]) that are not already listed in the [DOWNREF registry][17]? If so,
    list them.

The document is targeting Proposed Standard status. RFC 5912 is an
Informational RFC being referenced normatively from a Proposed Standard.
However, RFC 5912 is already listed in the DOWNREF registry, so no new downref
approval is required.

18. Are there normative references to documents that are not ready to be
    submitted to the IESG for publication or are otherwise in an unclear state?
    If so, what is the plan for their completion?

No. All normative references are to published RFCs.

19. Will publication of this document change the status of any existing RFCs? If
    so, does the Datatracker metadata correctly reflect this and are those RFCs
    listed on the title page, in the abstract, and discussed in the
    introduction? If not, explain why and point to the part of the document
    where the relationship of this document to these other RFCs is discussed.

No. This document does not update or obsolete any existing RFCs. It defines a
new otherName form that extends the framework defined in RFC 5280.

20. Describe the document shepherd's review of the IANA considerations section,
    especially with regard to its consistency with the body of the document.
    Confirm that all aspects of the document requiring IANA assignments are
    associated with the appropriate reservations in IANA registries. Confirm
    that any referenced IANA registries have been clearly identified. Confirm
    that each newly created IANA registry specifies its initial contents,
    allocations procedures, and a reasonable name (see [RFC 8126][11]).

The IANA Considerations section (Section 5) requests two assignments:

1. SMI Security for PKIX Module Identifier (1.3.6.1.5.5.7.0): TBD0 for
  id-mod-mac-address-other-name-2025. This is used in the ASN.1 module
  definition in Section 6.

2. SMI Security for PKIX Other Name Forms (1.3.6.1.5.5.7.8): TBD1 for
  id-on-MACAddress. This is the OID for the new otherName form, referenced
  throughout Sections 3 and 6.

The registries are correctly identified. No new registries are created. The
assignments are consistent with the body of the document.

21. List any new IANA registries that require Designated Expert Review for
    future allocations. Are the instructions to the Designated Expert clear?
    Please include suggestions of designated experts, if appropriate.

This document does not create any new IANA registries. No Designated Expert is
required.

[1]: https://www.ietf.org/about/groups/iesg/
[2]: https://www.rfc-editor.org/rfc/rfc4858.html
[3]: https://www.rfc-editor.org/rfc/rfc7942.html
[4]: https://wiki.ietf.org/group/ops/yang-review-tools
[5]: https://www.rfc-editor.org/rfc/rfc8342.html
[6]: https://wiki.ietf.org/group/iesg/ExpertTopics
[7]: https://www.rfc-editor.org/info/bcp79
[8]: https://www.ietf.org/tools/idnits/
[9]: https://www.rfc-editor.org/rfc/rfc3967.html
[10]: https://www.rfc-editor.org/info/bcp97
[11]: https://www.rfc-editor.org/rfc/rfc8126.html
[12]: https://www.rfc-editor.org/rfc/rfc2026.html#section-5
[13]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.1
[14]: https://www.rfc-editor.org/rfc/rfc2026.html#section-4.2
[15]: https://authors.ietf.org/en/content-guidelines-overview
[16]: https://www.ietf.org/about/groups/iesg/statements/normative-informative-references/
[17]: https://datatracker.ietf.org/doc/downref/