Bootstrapping TLS Encrypted ClientHello with DNS Service Bindings
draft-ietf-tls-svcb-ech-08

Received changes through RFC Editor sync (changed state to RFC, created became rfc relationship between draft-ietf-tls-svcb-ech and RFC 9848, changed IESG state to RFC Published)

[Ballot comment]
Hi Benjamin, Mike, and Erik,

Thanks for the effort put into this specification.

Thanks to Linda Dunbar for the OPSDIR review and to Ben for the follow-up.

Glad to see this piece of work finally making it to publication after de-clustering with SVCB/DNR/DDR.

Thanks for the follow-up clarifications provided by the authors and WG. Much appreciated.

I leave my OLD ballot and trust the authors/AD to decide about whether changes are needed.

=====OLD Ballot==

# DISCUSS

## The specification mixes DNS client behavior and TLS client behavior. Given that SVCB is a means among others to provide the ech configuration, I would expect that what a TLS client does with the ech configuration (especially how it feeds the connection establishment process) should be part of the ECH base spec, not individual configuration mechanisms.

## The procedure to place a connection (including the fallback part) may be impacted by the revised HE (HAPPY WG) given that HAPPY CHARTER includes the following:

==
Since the publication of RFC 8305, several changes to common protocols, clients, and
server deployments have occurred that require a revision of the algorithm. Some
of these include:
* Standardization and increased use of QUIC, which require updating the
TCP-specific parts of Happy Eyeballs.
* Introduction of Service Binding DNS resource records (SVCB and HTTPS RRs) that
provide richer service information and add priorities and parameters that
will change the sorting of addresses for Happy Eyeballs.
* Preparations for the standardization of TLS Encrypted Client Hello, which
can impact which servers a client is willing to connect to based on available
security properties.
* Increased deployment and refinement of IPv6-only and IPv6-mostly networks.

The HAPPY working group will deliver an updated version of the Happy Eyeballs
algorithm, "Happy Eyeballs Version 3", that incorporates changes to account for
these developments.
==

How do we plan to manage that dependency?

## Deployment/Implementation considerations: internal API to invoke an underlying resolution library

The TLS client may support ECH, a server may publish an ech configuration, but the internal API to invoke SVCB and receive the service parameters blob may not be available.

How existing OS libraries behave for passing service parameters? Do they parse the service parameters? Or is this passed blindly?

## Configurable behaviors and failure diagnostic

CURRENT:
  The SVCB-optional client behavior specified in (Section 3 of [SVCB])
  permits clients to fall back to a direct connection if all SVCB
  options fail.  This behavior is not suitable for ECH, because
  fallback would negate the privacy benefits of ECH.  Accordingly, ECH-
  capable SVCB-optional clients MUST switch to SVCB-reliant connection
  establishment if SVCB resolution succeeded (as defined in Section 3
  of [SVCB]) and all alternative endpoints have an "ech" SvcParam.

Why no provision is made for customized configurations (based on a user action) to control how fallback is handled? Also, how users are informed about the reasons of connection failures?

# Title: Expand SVCB

# Abstract: s/using a SVCB or HTTPS record/using a SVCB or HTTPS resource record (RR)

# Section 2: Consider adding terms used in the document (SVCP-optional, SVCB-reliant)

# Section 3: s/The "ech" SvcParamKey is defined for conveying/The "ech" SvcParamKey conveys

# Section 4: The first MUST is not about server behavior. Please consider a better title, e.g.,

s/Server behavior/Operational Considerations and TLS Server behavior

# IANA: maybe helpful for readers to include a pointer where the registry is available (https://www.iana.org/assignments/dns-svcb/dns-svcb.xhtml).

Cheers,
Med

[Ballot comment]
I want to thank Linda Dunbar for her OPSDIR review. In particular, she brings up this point in her review:

>> Additionally, diagnosing ECH failures can be difficult due to the lack of
>> fallback and visibility. The draft should recommend logging and monitoring
>> strategies to help operators detect misconfigurations.

> I don't believe we have any relevant recommendations for logging or monitoring.  Any such logging would likely not be related to the DNS records, so those recommendations would be in draft-ietf-tls-esni or a later draft.

I can understand Linda's concern. This document in particular, talks about how the client learns ECH configuration for the server and what its behavior should be given the ECH configuration. Implementors will therefore be looking at this document and not a later draft on what information should be logged. Is there no guidance that this document can provide in that regard?

[Ballot comment]
# Orie Steele, ART AD, comments for draft-ietf-tls-svcb-ech-07
CC @OR13

* line numbers:
  - https://author-tools.ietf.org/api/idnits?url=https://www.ietf.org/archive/id/draft-ietf-tls-svcb-ech-07.txt&submitcheck=True

* 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

Thanks to Barry Leiba for the ARTART review.

### degrade gracefully

```
121   These servers SHOULD support a protocol version that is compatible
122   with ECH.  At the time of writing, the compatible versions are TLS
123   1.3, DTLS 1.3, and QUIC version 1.  If the server does not support a
124   compatible version, each connection attempt will have to be retried,
125   delaying the connection and wasting resources.
```
...

```
137   fallback would negate the privacy benefits of ECH.  Accordingly, ECH-
138   capable SVCB-optional clients MUST switch to SVCB-reliant connection
139   establishment if SVCB resolution succeeded (as defined in Section 3
140   of [SVCB]) and all alternative endpoints have an "ech" SvcParam.
```

I found these requirements a bit difficult to parse.
I noted the mailing list discussion here:

https://mailarchive.ietf.org/arch/msg/tls/u2IbReogPhE-nbJz2EDYSjuxRv8/
https://mailarchive.ietf.org/arch/msg/tls/R_d2gDTmkGx-_dwh3iN_mFj6dyA/

I also note the security considerations section:

```
316   in cleartext.  To prevent downgrades, Section 3.1 of [SVCB]
317   recommends that clients abandon the connection attempt when such an
318   attack is detected.
```

I'm not an expert on TLS or ECH, so I found myself wondering if servers SHOULD/MUST support a protocol version that is compatible with ECH, specifically to avoid degrading gracefully.

[Ballot comment]
Thank you to Lucas Pardue for the GENART review.

** Section 9.  Please use the formal name of the registry:

OLD
  IANA is instructed to modify the Service Parameter Keys Registry
  entry for "ech" as follows:

NEW
IANA is instructed to modify the “DNS SVCB Service Parameter Keys (SvcParamKeys)”  Registry entry for "ech" as follows:

[Ballot discuss]
Hi Benjamin, Mike, and Erik,

Thanks for the effort put into this specification.

Thanks to Linda Dunbar for the OPSDIR review and to Ben for the follow-up.

Glad to see this piece of work finally making it to publication after de-clustering with SVCB/DNR/DDR.

I have a question on the write-up and some few DISCUSS points.

# Write-up

The write-up lists two implementations but I failed to find where in these two the ech service parameter is supported. It seems to me that these implems are more for the ECH support. Please consider updating as appropriate. Thanks.

# DISCUSS

## The specification mixes DNS client behavior and TLS client behavior. Given that SVCB is a means among others to provide the ech configuration, I would expect that what a TLS client does with the ech configuration (especially how it feeds the connection establishment process) should be part of the ECH base spec, not individual configuration mechanisms.

## The procedure to place a connection (including the fallback part) may be impacted by the revised HE (HAPPY WG) given that HAPPY CHARTER includes the following:

==
Since the publication of RFC 8305, several changes to common protocols, clients, and
server deployments have occurred that require a revision of the algorithm. Some
of these include:
* Standardization and increased use of QUIC, which require updating the
TCP-specific parts of Happy Eyeballs.
* Introduction of Service Binding DNS resource records (SVCB and HTTPS RRs) that
provide richer service information and add priorities and parameters that
will change the sorting of addresses for Happy Eyeballs.
* Preparations for the standardization of TLS Encrypted Client Hello, which
can impact which servers a client is willing to connect to based on available
security properties.
* Increased deployment and refinement of IPv6-only and IPv6-mostly networks.

The HAPPY working group will deliver an updated version of the Happy Eyeballs
algorithm, "Happy Eyeballs Version 3", that incorporates changes to account for
these developments.
==

How do we plan to manage that dependency?

## Deployment/Implementation considerations: internal API to invoke an underlying resolution library

The TLS client may support ECH, a server may publish an ech configuration, but the internal API to invoke SVCB and receive the service parameters blob may not be available.

How existing OS libraries behave for passing service parameters? Do they parse the service parameters? Or is this passed blindly?

## Configurable behaviors and failure diagnostic

CURRENT:
  The SVCB-optional client behavior specified in (Section 3 of [SVCB])
  permits clients to fall back to a direct connection if all SVCB
  options fail.  This behavior is not suitable for ECH, because
  fallback would negate the privacy benefits of ECH.  Accordingly, ECH-
  capable SVCB-optional clients MUST switch to SVCB-reliant connection
  establishment if SVCB resolution succeeded (as defined in Section 3
  of [SVCB]) and all alternative endpoints have an "ech" SvcParam.

Why no provision is made for customized configurations (based on a user action) to control how fallback is handled? Also, how users are informed about the reasons of connection failures?

[Ballot comment]
# Title: Expand SVCB

# Abstract: s/using a SVCB or HTTPS record/using a SVCB or HTTPS resource record (RR)

# Section 2: Consider adding terms used in the document (SVCP-optional, SVCB-reliant)

# Section 3: s/The "ech" SvcParamKey is defined for conveying/The "ech" SvcParamKey conveys

# Section 4: The first MUST is not about server behavior. Please consider a better title, e.g.,

s/Server behavior/Operational Considerations and TLS Server behavior

# IANA: maybe helpful for readers to include a pointer where the registry is available (https://www.iana.org/assignments/dns-svcb/dns-svcb.xhtml).

Cheers,
Med

[Ballot comment]
# Gunter Van de Velde, RTG AD, comments for draft-ietf-tls-svcb-ech-07

# The line numbers used are rendered from IETF idnits tool: https://author-tools.ietf.org/api/idnits?url=https://www.ietf.org/archive/id/draft-ietf-tls-svcb-ech-07.txt

# General Review
# ==============

100   In wire format, the value of the parameter is an ECHConfigList
101   (Section 4 of [ECH]), including the redundant length prefix.  In
102   presentation format, the value is the ECHConfigList in Base 64
103   Encoding (Section 4 of [RFC4648]).  Base 64 is used here to simplify
104   integration with TLS server software.  To enable simpler parsing,
105   this SvcParam MUST NOT contain escape sequences.
106
107 ech="AEj+DQBEAQAgACAdd+scUi0IYFsXnUIU7ko2Nd9+F8M26pAGZVpz/KrWPgAEAAEAAWQ
108 VZWNoLXNpdGVzLmV4YW1wbGUubmV0AAA="

GV> I used some tooling to decode this Base64 blob. It seems to decode into hex as follows:

0x0048fe0d004401002000201d77eb1c522d08605b179d4214ee4a3635df7e17c336ea9006655a73fcaad63e00040001000164156563682d73697465732e6578616d706c652e6e65740000

and that decodes as:

Bytes | Meaning
0048fe0d | Length of the ECHConfigList (72 bytes total)
00440100 | Start of ECHConfig (first part is version 0x0044, meaning draft-13 version of ECH)
2000201d77eb1c522d08605b179d4214ee4a3635df7e17c336ea9006655a73fcaad63e0 | Key configuration and public keys for encryption (big blob)
0040 | Length of public_name
0001 | Cipher suite count (one suite)
0001 | Cipher suite ID (indicates a specific cipher, e.g., TLS_AES_128_GCM_SHA256)
64 | Length of public_name string (100 bytes)
6563682d73697465732e6578616d706c652e6e6574 | "ech-sites.example.net" (this is the public name, in ASCII)
0000 | Padding/termination


Is the above is correct?
maybe it is worthwhile to add this decoding example from informational perspective within the draft if this decoding activity adds value?

G/

[Ballot comment]
Thanks for the work done in this document (and thanks for removing this part from the base SVCB I-D). Some suggestions below:

Titles of sections 4 and 5 should include "TLS" to remove any ambiguity with "DNS" server/client as the topic is about DNS.

Where is "SVCB-reliant" defined in `SVCB-reliant connection establishment` ?

While the examples of section 7 are welcome, I find the use of figure legends for explanations quite unreadable (notably because they are sometimes too concise and they do not clearly delineate the different examples).

IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-tls-svcb-ech-07. If any part of this review is inaccurate, please let us know.

IANA understands that, upon approval of this document, there is a single action which we must complete.

In the Service Parameter Keys (SvcParamKeys) registry in the DNS Service Bindings (SVCB) registry group located at:

https://www.iana.org/assignments/dns-svcb/

the existing registration:

Number: 5
Name: ech
Meaning: RESERVED (held for Encrypted ClientHello)
Change Controller: IETF

will be changed to:

Number: 5
Name: ech
Meaning: TLS Encrypted ClientHello Config
Change Controller: IETF

and its reference will be changed to [ RFC-to-be ].

We understand that this is the only action 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 2025-03-13):

From: The IESG
To: IETF-Announce
CC: draft-ietf-tls-svcb-ech@ietf.org, paul.wouters@aiven.io, sean@sn3rd.com, tls-chairs@ietf.org, tls@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Bootstrapping TLS Encrypted ClientHello with DNS Service Bindings) to Proposed Standard


The IESG has received a request from the Transport Layer Security WG (tls) to
consider the following document: - 'Bootstrapping TLS Encrypted ClientHello
with DNS Service Bindings'
  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 2025-03-13. 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


  To use TLS Encrypted ClientHello (ECH) the client needs to learn the
  ECH configuration for a server before it attempts a connection to the
  server.  This specification provides a mechanism for conveying the
  ECH configuration information via DNS, using a SVCB or HTTPS record.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-tls-svcb-ech/



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

IESG/Authors/WG Chairs:

IANA has completed its review of draft-ietf-tls-svcb-ech-06. If any part of this review is inaccurate, please let us know.

IANA understands that, upon approval of this document, there is a single action which we must complete.

In the Service Parameter Keys (SvcParamKeys) registry in the DNS Service Bindings (SVCB) registry group located at:

https://www.iana.org/assignments/dns-svcb/

The existing registration for Number: 5; Name: ech will be modified to be the following:

Number: 5
Name: ech
Meaning: TLS Encrypted ClientHello Config
Change Controller: IETF
Reference: [ RFC-to-be ]

We understand that this is the only action required to be completed upon approval of this document.

NOTE: The action 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 action 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 2024-11-15):

From: The IESG
To: IETF-Announce
CC: draft-ietf-tls-svcb-ech@ietf.org, paul.wouters@aiven.io, sean@sn3rd.com, tls-chairs@ietf.org, tls@ietf.org
Reply-To: last-call@ietf.org
Sender:
Subject: Last Call:  (Bootstrapping TLS Encrypted ClientHello with DNS Service Bindings) to Proposed Standard


The IESG has received a request from the Transport Layer Security WG (tls) to
consider the following document: - 'Bootstrapping TLS Encrypted ClientHello
with DNS Service Bindings'
  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 2024-11-15. 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


  To use TLS Encrypted ClientHello (ECH) the client needs to learn the
  ECH configuration for a server before it attempts a connection to the
  server.  This specification provides a mechanism for conveying the
  ECH configuration information via DNS, using a SVCB or HTTPS record.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-tls-svcb-ech/



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?

This I-D represents the consensus on the WG.

Please note that the text in this I-D was initially developed in the DNSOP WG,
went through IETF LC, and IESG review. The result of the IESG review was to take
the text in this I-D out of RFC 9460 (was draft-ietf-dnsop-svcb-http) and run the
new I-D through the TLS WG. The text in this I-D is essentially the same text
taken from -11 of draft-ietf-dnsop-svcb-http. In some respects, you could claim
that this I-D has consensus from multiple WGs.

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

There are two things that might be considered controversial and I am stretching here:
How this I-D arrived at TLS. Ben provided a good explanation here:
https://mailarchive.ietf.org/arch/msg/tls/Vct8iUc4IgSHENX2r9IGOQFLkyk/
ECH itself, but that seems to have subside.

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.)

There have been no threats of appeal.

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)?

This specification is implemented today by Chrome, Firefox, and Safari [1],
and is deployed on all Cloudflare free tier domains [2].

[1] https://chromestatus.com/feature/6196703843581952
[2] https://blog.cloudflare.com/announcing-encrypted-client-hello


## 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.

As noted earlier, this I-D is about DNS service records and I’d argue there is
not a lot of expertise in the TLS WG on DNS, but the authors are experts. We
also made sure to get an early review from the DNSDIR; see
https://datatracker.ietf.org/doc/review-ietf-tls-svcb-ech-01-dnsdir-early-lemon-2024-03-29/.
The DNSDIR comments were discussed and resolved; see
https://mailarchive.ietf.org/arch/msg/tls/VQcqUuOXSE8sgcp4_CHa6Jlc394/.

Again, the text of this I-D is largely unchanged from what went through
IETF LC and IESG review as draft-ietf-dnsop-svcb-http before being separated
from what became RFC 9460. It was thoroughly reviewed at that point, and
modifications since then have been minimal.

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.

Note that the underlying protocol (ECH) has undergone security analysis as documented
in https://www.cs.ox.ac.uk/people/vincent.cheval/publis/BCW-ccs22.pdf.

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?

The Shepherd believes that this document is ready to go.

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?

Note that text in this I-D has already been through IETF LC.

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?

Standards Track is requested. While the registry does not require Standards Track,
Standards Track is appropriate for this I-D because: It was ripped from a Standards
Track RFC, i.e., it would have been in RFC 9460 except for timing. There is sufficient
interest from implementers in supporting ECH with SVCB.

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 Shepherd has confirmed with the authors that all required disclosures have been
filed.

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 Shepherd has confirmed with the authors that all are willing to be an author.

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.)

-04 had some nits, but -05 addresses them.

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

There are not many references and they seem to be categorized correctly.

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

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.

This I-D includes a reference to draft-ietf-tls-esni, but this I-D will progress
with that I-D so the references will be resolved as part of the cluster the RFC
editor will create.

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?

See q17.

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.

N/A

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 authors of this I-D created the registry that this I-D registers values in so
there is little chance we got this wrong. The Shepherd double checked that the 5
columns needed for the registry are included and appropriate for this registration.

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.*

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?

This I-D represents the consensus on the WG.

Please note that the text in this I-D was initially developed in the DNSOP WG,
went through IETF LC, and IESG review. The result of the IESG review was to take
the text in this I-D out of RFC 9460 (was draft-ietf-dnsop-svcb-http) and run the
new I-D through the TLS WG. The text in this I-D is essentially the same text
taken from -11 of draft-ietf-dnsop-svcb-http. In some respects, you could claim
that this I-D has consensus from multiple WGs.

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

There are two things that might be considered controversial and I am stretching here:
How this I-D arrived at TLS. Ben provided a good explanation here:
https://mailarchive.ietf.org/arch/msg/tls/Vct8iUc4IgSHENX2r9IGOQFLkyk/
ECH itself, but that seems to have subside.

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.)

There have been no threats of appeal.

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)?

This specification is implemented today by Chrome, Firefox, and Safari [1],
and is deployed on all Cloudflare free tier domains [2].

[1] https://chromestatus.com/feature/6196703843581952
[2] https://blog.cloudflare.com/announcing-encrypted-client-hello


## 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.

As noted earlier, this I-D is about DNS service records and I’d argue there is
not a lot of expertise in the TLS WG on DNS, but the authors are experts. We
also made sure to get an early review from the DNSDIR; see
https://datatracker.ietf.org/doc/review-ietf-tls-svcb-ech-01-dnsdir-early-lemon-2024-03-29/.
The DNSDIR comments were discussed and resolved; see
https://mailarchive.ietf.org/arch/msg/tls/VQcqUuOXSE8sgcp4_CHa6Jlc394/.

Again, the text of this I-D is largely unchanged from what went through
IETF LC and IESG review as draft-ietf-dnsop-svcb-http before being separated
from what became RFC 9460. It was thoroughly reviewed at that point, and
modifications since then have been minimal.

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.

Note that the underlying protocol (ECH) has undergone security analysis as documented
in https://www.cs.ox.ac.uk/people/vincent.cheval/publis/BCW-ccs22.pdf.

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?

The Shepherd believes that this document is ready to go.

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?

Note that text in this I-D has already been through IETF LC.

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?

Standards Track is requested. While the registry does not require Standards Track,
Standards Track is appropriate for this I-D because: It was ripped from a Standards
Track RFC, i.e., it would have been in RFC 9460 except for timing. There is sufficient
interest from implementers in supporting ECH with SVCB.

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 Shepherd has confirmed with the authors that all required disclosures have been
filed.

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 Shepherd has confirmed with the authors that all are willing to be an author.

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.)

-04 had some nits, but -05 addresses them.

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

There are not many references and they seem to be categorized correctly.

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

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.

This I-D includes a reference to draft-ietf-tls-esni, but this I-D will progress
with that I-D so the references will be resolved as part of the cluster the RFC
editor will create.

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?

See q17.

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.

N/A

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 authors of this I-D created the registry that this I-D registers values in so
there is little chance we got this wrong. The Shepherd double checked that the 5
columns needed for the registry are included and appropriate for this registration.

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.*

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?

This I-D represents the consensus on the WG.

Please note that the text in this I-D was initially developed in the DNSOP WG,
went through IETF LC, and IESG review. The result of the IESG review was to take
the text in this I-D out of RFC 9460 (was draft-ietf-dnsop-svcb-http) and run the
new I-D through the TLS WG. The text in this I-D is essentially the same text
taken from -11 of draft-ietf-dnsop-svcb-http. In some respects, you could claim
that this I-D has consensus from multiple WGs.

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

There are two things that might be considered controversial and I am stretching here:
How this I-D arrived at TLS. Ben provided a good explanation here:
https://mailarchive.ietf.org/arch/msg/tls/Vct8iUc4IgSHENX2r9IGOQFLkyk/
ECH itself, but that seems to have subside.

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.)

There have been no threats of appeal.

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)?

This specification is implemented today by Chrome, Firefox, and Safari [1],
and is deployed on all Cloudflare free tier domains [2].

[1] https://chromestatus.com/feature/6196703843581952
[2] https://blog.cloudflare.com/announcing-encrypted-client-hello


## 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.

As noted earlier, this I-D is about DNS service records and I’d argue there is
not a lot of expertise in the TLS WG on DNS, but the authors are experts. We
also made sure to get an early review from the DNSDIR; see
https://datatracker.ietf.org/doc/review-ietf-tls-svcb-ech-01-dnsdir-early-lemon-2024-03-29/.
The DNSDIR comments were discussed and resolved; see
https://mailarchive.ietf.org/arch/msg/tls/VQcqUuOXSE8sgcp4_CHa6Jlc394/.

Again, the text of this I-D is largely unchanged from what went through
IETF LC and IESG review as draft-ietf-dnsop-svcb-http before being separated
from what became RFC 9460. It was thoroughly reviewed at that point, and
modifications since then have been minimal.

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?

The Shepherd believes that this document is ready to go.

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?

Note that text in this I-D has already been through IETF LC.

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?

Standards Track is requested. While the registry does not require Standards Track,
Standards Track is appropriate for this I-D because: It was ripped from a Standards
Track RFC, i.e., it would have been in RFC 9460 except for timing. There is sufficient
interest from implementers in supporting ECH with SVCB.

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 Shepherd has confirmed with the authors that all required disclosures have been
filed.

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 Shepherd has confirmed with the authors that all are willing to be an author.

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.)

-04 had some nits, but -05 addresses them.

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

There are not many references and they seem to be categorized correctly.

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

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.

This I-D includes a reference to draft-ietf-tls-esni, but this I-D will progress
with that I-D so the references will be resolved as part of the cluster the RFC
editor will create.

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?

See q17.

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.

N/A

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 authors of this I-D created the registry that this I-D registers values in so
there is little chance we got this wrong. The Shepherd double checked that the 5
columns needed for the registry are included and appropriate for this registration.

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/

The -02 version addresses DNSDIR review comments. As there are no none open issues (no issues/PRs in the Github repo nor issues on the list), it's time to issue a WGLC.