In the DNS, QDCOUNT is (usually) One
draft-ietf-dnsop-qdcount-is-one-04

Received changes through RFC Editor sync (changed state to RFC, created became rfc relationship between draft-ietf-dnsop-qdcount-is-one and RFC 9619, changed IESG state to RFC Published)

[Ballot comment]
Section 3, paragraph 1
>    A brief summary of the guidance provided in the existing DNS
>    specification for the use of QDCOUNT can be found in Appendix A.
>    While the specification is clear in many cases, in the specific case
>    of OPCODE = 0 (QUERY) there is some ambiguity which this document
>    aims to eliminate.


By "existing DNS specification" do you mean RFC1035? Please state so.

[Ballot comment]

# Éric Vyncke, INT AD, comments for draft-ietf-dnsop-qdcount-is-one-03

Thank you for the work put into this document.

Please find below some non-blocking COMMENT points (but replies would be appreciated even if only for my own education), and some nits.

Special thanks to Suzanne Woolf for the shepherd's detailed write-up including the WG consensus *and* the justification of the intended status.

I hope that this review helps to improve the document,

Regards,

-éric


# COMMENTS (non-blocking)

## Meta data

As noted by Roman and the idnits, please use only numbers in the "Updates" tag.

## Section 1

It is somehow ambiguous who are the "we" often used in this section: is it the authors ? the WG ? the IETF ? Using passive voice (or alternatives) would avoid this ambiguity.

## Appendix A.1

Suggest adding a reference to BCP14 in `normative requirements keyword`

# NITS (non-blocking / cosmetic)

## Generic

The repetition of `OPCODE = 0 (QUERY)` is an eye distraction, please consider using on "QUERY" after the first occurence.

## Section 1

s/Question Section of a message/Question Section of a DNS message/ ?

[Ballot comment]
** idnits says

  == The 'Updates: ' line in the draft header should list only the _numbers_
    of the RFCs which will be updated by this document (if approved); it
    should not include the word 'RFC' in the list.

** Section 4.
  Firewalls that process DNS messages in order to eliminate unwanted
  traffic SHOULD treat messages with OPCODE = 0 and QDCOUNT > 1 as
  malformed traffic and return a FORMERR response as described above.
  Such firewalls MUST NOT treat messages with OPCODE = 0 and QDCOUNT =
  0 as malformed.  See Section 4 of [RFC8906] for further guidance.

(Editorial) Should the term “firewall” be generalized to “middle box” (or something similar)?  I ask because I’m wondering if DNS proxies, UTMs, or IPSs should also follow this advice?

[Ballot comment]
Section 4.
  Firewalls that process DNS messages in order to eliminate unwanted
  traffic SHOULD treat messages with OPCODE = 0 and QDCOUNT > 1 as
  malformed traffic and return a FORMERR response as described above.
  Such firewalls MUST NOT treat messages with OPCODE = 0 and QDCOUNT =
  0 as malformed.  See Section 4 of [RFC8906] for further guidance.

(Editorial) Should the term “firewall” be generalized to “middle box” (or something similar)?  I ask because I’m wondering if DNS proxies, UTMs, or IPSs should also follow this advice?

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-dnsop-qdcount-is-one-03, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any registry actions.

While it's often helpful for a document's IANA Considerations section to remain in place upon publication even if there are no actions, if the authors strongly prefer to remove it, we do not object.

If this assessment is not accurate, please respond as soon as possible.

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 2024-06-12):

From: The IESG
To: IETF-Announce
CC: dnsop-chairs@ietf.org, dnsop@ietf.org, draft-ietf-dnsop-qdcount-is-one@ietf.org, suzworldwide@gmail.com, warren@kumari.net
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (In the DNS, QDCOUNT is (usually) One) to Proposed Standard


The IESG has received a request from the Domain Name System Operations WG
(dnsop) to consider the following document: - 'In the DNS, QDCOUNT is
(usually) One'
  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 2024-06-12. 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 updates RFC 1035 by constraining the allowed value of
  the QDCOUNT parameter in DNS messages with OPCODE = 0 (QUERY) to a
  maximum of one, and specifies the required behaviour when values that
  are not allowed are encountered.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-dnsop-qdcount-is-one/



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.*


## 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 has broad consensus, particularly in the sense that it was kept as short as possible to address a specific point of ambiguity in the standard (RFC 1035). Specifically, RFC 1035 doesn't constrain QDCOUNT (query count) for a query to be either 0 or 1, but other protocol constraints imply it and common implementation practice does limit it.

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

There was some discussion in the WGLC about whether to change the title of the document and whether to expand its scope to discuss DNS cookies (RFC 7873). In both cases it seemed likely to add complexity for limited or no benefit.

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

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)?

The document addresses long-standing ambiguity in the spec in favor of making the spec consistent with actual practice. This issue is fully addressed in the document.

## 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.

The DNS directorate early review judged it "ready". Since the draft specifically addresses an ambiguity in the DNS specification, and does not suggest any change to implementations, others did not seem 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.

N/A

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]?

N/A

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.

N/A

## 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?

Yes. It fixes an ambiguity that made existing practice appear inconsistent with the standard; it's clear about the scope of the change; WG members have found it straightforward to understand; and it can go forward.

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?

N/A

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?

As stated, it's intended as Proposed Standard, as it clarifies an existing Internet Standard.

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.

Yes.

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.

Yes.

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.)

Header needs to drop "RFC" from the Updates: field; abstract needs to mention updating 1035; Status: field needs to be specific. These are minor and can be tended to with other required updates prior to IETF last call.

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

No

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?
No

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.

No

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

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

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]).

There are no IANA actions in this document and the IANA Considerations section says so.

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.
N/A

[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.*


## 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 has broad consensus, particularly in the sense that it was kept as short as possible to address a specific point of ambiguity in the standard (RFC 1035). Specifically, RFC 1035 doesn't constrain QDCOUNT (query count) for a query to be either 0 or 1, but other protocol constraints imply it and common implementation practice does limit it.

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

There was some discussion in the WGLC about whether to change the title of the document and whether to expand its scope to discuss DNS cookies (RFC 7873). In both cases it seemed likely to add complexity for limited or no benefit.

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

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)?

The document addresses long-standing ambiguity in the spec in favor of making the spec consistent with actual practice. This issue is fully addressed in the document.

## 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.

The DNS directorate early review judged it "ready". Since the draft specifically addresses an ambiguity in the DNS specification, and does not suggest any change to implementations, others did not seem 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.

N/A

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]?

N/A

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.

N/A

## 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?

Yes. It fixes an ambiguity that made existing practice appear inconsistent with the standard; it's clear about the scope of the change; WG members have found it straightforward to understand; and it can go forward.

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?

N/A

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?

As stated, it's intended as Proposed Standard, as it clarifies an existing Internet Standard.

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.

Yes.

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.

Yes.

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.)

Header needs to drop "RFC" from the Updates: field; abstract needs to mention updating 1035; Status: field needs to be specific. These are minor and can be tended to with other required updates prior to IETF last call.

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

No

16. List any normative references that are not freely available to anyone. Did
    the community have sufficient access to review any such normative
    references?
No

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.

No

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

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

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]).

There are no IANA actions in this document and the IANA Considerations section says so.

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.
N/A

[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/