Split DNS Configuration for the Internet Key Exchange Protocol Version 2 (IKEv2)
draft-ietf-ipsecme-split-dns-17

[Ballot comment]
Thank you for addressing my DISCUSS.
I still don't love this idea / solution, but after asking the DNSOP list for review (https://www.ietf.org/mail-archive/web/dnsop/current/msg24835.html) and getting feedback (https://www.ietf.org/mail-archive/web/dnsop/current/msg24881.html) I've been persuaded that the benefits (with the mitigations) outweigh the risks.




---- Original DISCUSS position ----
I hope I'm just missing something obvious here, but this seems like it may cause a significant security issue.

Lots of "regular" users use VPNs for access the Internet, either to bypass censorship / content restrictions, or to improve their privacy. These are not "corporate" / "enterprise" VPNs, but rather public ones - and sometimes they are run by people I wouldn't entirely trust.

What is to stop one of these VPN providers setting:
INTERNAL_DNS_DOMAIN(www.paypal.com)
INTERNAL_DNSSEC_TA(43547,8,1,B6225AB2CC613E0DCA7962BDC2342EA4...)

or, better yet:
INTERNAL_DNS_DOMAIN(com)
INTERNAL_DNSSEC_TA(43547,8,1,B6225AB2CC613E0DCA7962BDC2342EA4...)

and so being able to spoof DNSSEC for paypal.com / all of .com?
This is especially worrying if something like DANE is ever deployed...

The draft *does* says:
"Other generic or public domains, such as top-level domains, similarly SHOULD NOT be whitelisted." - this doesn't really answer the above.
1: It is increasingly hard to know what is a "real" TLD (.internal? .bank? .home?)
2: How do I programatically tell if www.foo.net is a "public domain"? What is a public domain anyway?
How is an implementer supposed to address this?

It also says:
"Any updates to this whitelist of domain names MUST happen via explicit human interaction to prevent invisible installation of trust anchors."
Is my auntie really expected (or competent) to understand what "Your VPN provider, TrustVPN wants to whitelist com. Do you want to allow this? [Y/N]" means?

I'm hoping that I'm completely misunderstanding how the INTERNAL_DNSSEC_TA bit works.

Also, some of the DNS behavior is handwavey - I think that the document really should be reviewed by DNSOP, but will leave it to Eric to make that call.

--------------



This section: " The content of INTERNAL_DNS_DOMAIN and INTERNAL_DNSSEC_TA may be
  passed to another (DNS) program for processing.  As with any network
  input, the content SHOULD be considered untrusted and handled
  accordingly." feels a bit handwavey. Are there currently any DNSSEC validating clients which can easily take a targeted TA for a specific domain / set of domains?

I’m also not quite sure how this interacts with delegations. E.g:

example.com  600 IN NS ns01.internal.example
And then INTERNAL_DNS_DOMAIN(internal.example) — if the client runs a local recursive, does it need to send the query to ns01 though the VPN or not?

[Ballot comment]
Thanks for the time and effort invested in this document. I'm also very interested to see the resolution to Warren's DISCUSS regarding ipsecme-split-dns being used as an easy tool to over-claim entire sections of the DNS hierarchy. Perhaps specifying that the DOMAIN and TA sent to the client MUST be in the administrative control of the VPN provider (I'm not sure I read that in the draft) might be one way out, yet I wonder if this is a case of simply having to trust that the VPN provider does the right thing (as cold as that leaves me) regardless of the words in the document.

[Ballot comment]
I'm also very interested to see the resolution to Warren's DISCUSS regarding ipsecme-split-dns being used as an easy tool to over-claim entire sections of the DNS hierarchy.

[Ballot comment]
- General: Once my client signals support for split DNS, what prevents a server from over claiming the domains that should be resolved via the private DNS servers? Perhaps for purposes of employee monitoring or censoring NTFW domains? (I've known some IT managers who would think that was a fine idea.)

§6: "the IKE connection SHOULD only process
the DNS information if the two connections are part of the same
logical entity"
How does a client determine the connections are part of the same logical entity? I can think of some ways, but I think the draft should be give some explicit guidance.

[Ballot discuss]
I hope I'm just missing something obvious here, but this seems like it may cause a significant security issue.

Lots of "regular" users use VPNs for access the Internet, either to bypass censorship / content restrictions, or to improve their privacy. These are not "corporate" / "enterprise" VPNs, but rather public ones - and sometimes they are run by people I wouldn't entirely trust.

What is to stop one of these VPN providers setting:
INTERNAL_DNS_DOMAIN(www.paypal.com)
INTERNAL_DNSSEC_TA(43547,8,1,B6225AB2CC613E0DCA7962BDC2342EA4...)

or, better yet:
INTERNAL_DNS_DOMAIN(com)
INTERNAL_DNSSEC_TA(43547,8,1,B6225AB2CC613E0DCA7962BDC2342EA4...)

and so being able to spoof DNSSEC for paypal.com / all of .com?
This is especially worrying if something like DANE is ever deployed...

The draft *does* says:
"Other generic or public domains, such as top-level domains, similarly SHOULD NOT be whitelisted." - this doesn't really answer the above.
1: It is increasingly hard to know what is a "real" TLD (.internal? .bank? .home?)
2: How do I programatically tell if www.foo.net is a "public domain"? What is a public domain anyway?
How is an implementer supposed to address this?

It also says:
"Any updates to this whitelist of domain names MUST happen via explicit human interaction to prevent invisible installation of trust anchors."
Is my auntie really expected (or competent) to understand what "Your VPN provider, TrustVPN wants to whitelist com. Do you want to allow this? [Y/N]" means?

I'm hoping that I'm completely misunderstanding how the INTERNAL_DNSSEC_TA bit works.

Also, some of the DNS behavior is handwavey - I think that the document really should be reviewed by DNSOP, but will leave it to Eric to make that call.

[Ballot comment]
This section: " The content of INTERNAL_DNS_DOMAIN and INTERNAL_DNSSEC_TA may be
  passed to another (DNS) program for processing.  As with any network
  input, the content SHOULD be considered untrusted and handled
  accordingly." feels a bit handwavey. Are there currently any DNSSEC validating clients which can easily take a targeted TA for a specific domain / set of domains?

I’m also not quite sure how this interacts with delegations. E.g:

example.com  600 IN NS ns01.internal.example
And then INTERNAL_DNS_DOMAIN(internal.example) — if the client runs a local recursive, does it need to send the query to ns01 though the VPN or not?

[Ballot comment]
* Sections 3.1 and 7

I have a hard time seeing why the length of the INTERNAL_DNS_DOMAIN attribute would ever be zero. Do you expect someone to send an empty attribute? If not, the attribute definition should be updated in Section 7.

* Meta comment

Since the draft needs and uses a lot of example domain names, I would suggest using a reserved TLD (e.g. ".example") from BCP32 to build up the examples instead of using registered domain names.

[Ballot discuss]
I hope I'm just missing something obvious here, but this seems like it may cause a significant security issue.

Lots of "regular" users use VPNs for access the Internet, either to bypass censorship / content restrictions, or to improve their privacy. These are not "corporate" / "enterprise" VPNs, but rather public ones - and sometimes they are run by people I wouldn't entirely trust.

What is to stop one of these VPN providers setting:
INTERNAL_DNS_DOMAIN(www.paypal.com)
INTERNAL_DNSSEC_TA(43547,8,1,B6225AB2CC613E0DCA7962BDC2342EA4...)

or, better yet:
INTERNAL_DNS_DOMAIN(com)
INTERNAL_DNSSEC_TA(43547,8,1,B6225AB2CC613E0DCA7962BDC2342EA4...)

and so being able to spoof DNSSEC for paypal.com / all of .com?
This is especially worrying if something like DANE is ever deployed...

The draft *does* says:
"Other generic or public domains, such as top-level domains, similarly SHOULD NOT be whitelisted." - this doesn't really answer the above.
1: It is increasingly hard to know what is a "real" TLD (.internal? .bank? .home?)
2: How do I programatically tell if www.foo.net is a "public domain"? What is a public domain anyway?
How is an implementer supposed to address this?

It also says:
"Any updates to this whitelist of domain names MUST happen via explicit human interaction to prevent invisible installation of trust anchors."
Is my auntie really expected (or competent) to understand what "Your VPN provider, TrustVPN wants to whitelist com. Do you want to allow this? [Y/N]" means?

I'm hoping that I'm completely misunderstanding what the INTERNAL_DNSSEC_TA bit does - please help allay my fears...

[Ballot comment]
This section: " The content of INTERNAL_DNS_DOMAIN and INTERNAL_DNSSEC_TA may be
  passed to another (DNS) program for processing.  As with any network
  input, the content SHOULD be considered untrusted and handled
  accordingly." feels a bit handwavey. Are there currently any DNSSEC validating clients which can easily take a targeted TA for a specific domain / set of domains?

[Ballot comment]
Perhaps it would be helpful to give an example of why

  A client using these configuration payloads will be able to request
  and receive Split DNS configurations using the INTERNAL_DNS_DOMAIN
  and INTERNAL_DNSSEC_TA configuration attributes.  The client device
  can use the internal DNS server(s) for any DNS queries within the
  assigned domains.  DNS queries for other domains SHOULD be sent to
  the regular external DNS server.

DNS queries for other domains might not be sent to the regular external DNS server? I'm thinking of one, but I'm flat-out guessing.

[Ballot comment]
Thanks to everyone who worked on this document. It seems a very useful extension
to IKEv2. I have a handful of minor and editorial comments that you may want to
consider addressing.

---------------------------------------------------------------------------

Please expand "IKEv2" in the title and abstract. See
https://www.rfc-editor.org/materials/abbrev.expansion.txt for details.

---------------------------------------------------------------------------

§2.1:

>  To indicate support for Split DNS, an initiator includes one more
>  INTERNAL_DNS_DOMAIN attributes as defined in Section 3 as part of the
>  CFG_REQUEST payload.

I can't parse this. Is it mean to say "...one or more..."? Or is "attributes"
supposed to be "attribute"?

---------------------------------------------------------------------------

§2.1:

>  includes an INTERNAL_DNSSEC_TA attribute, but does not inclue an

Nit: "include"

---------------------------------------------------------------------------

§2.1:

>  An initiator MAY convey its current DNSSEC trust anchors for the
>  domain specified in the INTERNAL_DNS_DOMAIN attribute.  If it does
>  not wish to convey this information, it MUST use a length of 0.

As an implementor, I would have no idea whether this was something I wanted to
include. If it is configurable, then I would have no idea as an operator whether
how to set such configuration. Could we add some guidance here about when
implementations and/or operators might want to send this, and when they might
not?

---------------------------------------------------------------------------

§2.4.1:

>  The responder replies with two DNS server addresses, and two internal
>  domains, "example.com" and "city.other.com".

The domain "other.com" appears to be in active use by an organization known as
"Other Entertainment." Please consider using an example domain as described in
RFC 2606 section 2 or 3.

---------------------------------------------------------------------------

§2.4.2:

>  In this example, the initiator has no existing DNSSEC trust anchors
>  would the requested domain. the "example.com" dommain has DNSSEC

Nit: "...domain. The..."

---------------------------------------------------------------------------

§4:

>  For example, if the INTERNAL_DNS_DOMAIN attribute
>  specifies "example.com", then "example.com", "www.example.com" and
>  "mail.eng.example.com" MUST be resolved using the internal DNS
>  resolver(s), but "anotherexample.com" and "ample.com" SHOULD NOT be
>  resolved using the internal resolver and SHOULD use the system's
>  external DNS resolver(s).

The domain "anotherexample.com" is in use by a personal web site. The domain
"ample.com" is registered anonymously through Amazon.com. For this example that
needs to show a domain whose name is a subset of the indicated domain, please
consider using an example domain as described in RFC 2602 section 2.

---------------------------------------------------------------------------

§5:

>  DNS records can be used to publish specific records containing trust
>  anchors for applications.  The most common record type is the TLSA
>  record specified in [RFC6698].  This DNS record type publishes which
>  CA certificate or EE certificate to expect for a certain host name.

Please expand "CA" and "EE".

---------------------------------------------------------------------------

§5:

>  In most deployment scenario's, the IKE client has an expectation that

Nit: "scenarios"

[Ballot comment]
Section 5:

"Enterprise Certificate Agency" --> I would have expected this to say Enterprise Certificate Authority.

"Other generic or public domains, such as top-level domains, similarly SHOULD NOT be whitelisted." Under what exceptional circumstances would it make sense to whitelist a TLD? Is this like if I run Example Corp and I own .example?

[Ballot discuss]
This is a well written document, so thank you for that.
I've noticed that Benjamin already found typos that I found and raised one of the same questions, but I think this is important enough to be addressed before I recommend approval of this document. Specifically:

In Section 3.1:

  o  Domain Name (0 or more octets) - A Fully Qualified Domain Name
      used for Split DNS rules, such as "example.com", in DNS
      presentation format and optionally using IDNA [RFC5890] for
      Internationalized Domain Names.

Do you mean A-label or U-label form here?

      Implementors need to be careful
      that this value is not null-terminated.

[Ballot comment]
I am balloting YES because I think this mechanism has significant value, but I do also
have some substantial comments that will likely result in changes to the draft.
(I also have a number of nit-level comments.)

Section 1

nit: the Abstract and Introduction are supposed to stand on their own, so
starting off with "Split DNS is a common configuration" before defining it
makes the reader work a bit harder than perhaps they need to.

Section 2

                                                      When Split DNS
  has been negotiated, the existing DNS server configuration attributes
  will be interpreted as internal DNS servers that can resolve
  hostnames within the internal domains.

nit: maybe add a word or two to emphasize that the existing attributes are
also IKEv2 Configuration Payload Attributes?

Section 2.1

                        If an INTERNAL_DNS_DOMAIN attribute is included
  in the CFG_REQUEST, the initiator MUST also include one or more
  INTERNAL_IP4_DNS and INTERNAL_IP6_DNS attributes in the CFG_REQUEST.

nit: I think I could parse this as saying that I need one or more IP4 and also
one or more IP6 attributes (i.e., precluding v4- or v6-only
configurations), which I assume is not the intent.  Maybe "or" or "and/or"
would be better than "and"?

  To indicate support for DNSSEC, an initiator includes one or more
  INTERNAL_DNSSEC_TA attributes as defined in Section 3 as part of the
  CFG_REQUEST payload. [...]

nit: There are perhaps philosophical arguments to have about whether this
indicates support for DNSSEC as a whole, or just for receiving trust
anchors for DNSSEC from the responder [for the split-DNS domain(s)].

Section 2.2

  supported by the server, unless the initiator has been configured
  with local polict to define a set of Split DNS domains to use by
  default.

typo: "policy"

We have to use DNS presentation format for the DS records and not wire
format?

Section 2.4

Please consider using IPv6 examples, per
https://www.iab.org/2016/11/07/iab-statement-on-ipv6/ .

Section 3.1

  o  Domain Name (0 or more octets) - A Fully Qualified Domain Name
      used for Split DNS rules, such as "example.com", in DNS
      presentation format and optionally using IDNA [RFC5890] for
      Internationalized Domain Names.  Implementors need to be careful
      that this value is not null-terminated.

W.r.t. IDNA, is this an A-label or a U-label?
W.r.t NUL-termination, do they need to not send the zero byte or not expect
to receive one?

Section 3.2

                                                    Any
  INTERNAL_DNSSEC_TA attribute that is not immediately preceded by an
  INTERNAL_DNS_DOMAIN or another INTERNAL_DNSSEC_TA attribute applying
  to the same domain name MUST be ignored and treated as a protocol
  error.

Isn't "ignored" incompatible with "treated as a protocol error"?

Section 4

  If a client is configured by local policy to only accept a limited
  number of INTERNAL_DNS_DOMAIN values, the client MUST ignore any
  other INTERNAL_DNS_DOMAIN values.

Is this a limited *number* or a limited *set*?  (If the former, exposition
about which ones are the "other" ones is probably in order.)

  private remote network using the IPsec connection.  If all traffic is
  routed over the IPsec connection, the existing global
  INTERNAL_IP4_DNS and INTERNAL_IP6_DNS can be used without creating
  specific DNS exemptions.

DNS or DNSSEC exemptions (i.e., both)?

Section 5

  DNS records can be used to publish specific records containing trust
  anchors for applications.  The most common record type is the TLSA
  record specified in [RFC6698].  This DNS record type publishes which
  CA certificate or EE certificate to expect for a certain host name.
  These records are protected by DNSSEC and thus can be trusted by the
  application.  [...]

I'm probably thinking too much about "trust" as a concept (due to the RATS
BoF), but especially given that this goes on to say that this is a local
policy decision, I'd suggest replacing "can be trusted" with something like
"has a trust path in" or "are trustable by".  Merely being in DNS with
valid DNSSEC signatures does not make the client trust it; that's still a
local policy decision.

                It allows the remote IKE/IPsec server to modify DNS
  answers including its DNSSEC cryptographic signatures by overriding
  existing DNS information with trust anchor conveyed via IKE and
  (temporarilly) installed on the IKE client. [...]

nits: "including DNSSEC cryptographic signatures" (no "its"); "trust
anchor(s)"

  IKE clients willing to accept INTERNAL_DNSSEC_TA attributes MUST use
  a whitelist of one or more domains that can be updated out of band.
  IKE clients with an empty whitelist MUST NOT use any
  INTERNAL_DNSSEC_TA attributes received over IKE.  Such clients MAY
  interpret receiving an INTERNAL_DNSSEC_TA attribute for a non-
  whitelisted domain as an indication that their local configuration
  may need to be updated out of band.
[...]
  IKE clients MAY interpret an INTERNAL_DNSSEC_TA for domain that was
  not preconfigured as an indication that it needs to update its IKE
  configuration (out of band).  The client MUST NOT use such a
  INTERNAL_DNSSEC_TA to reconfigure its local DNS settings.

These two paragraphs seem essentially redundant (the first seems better to
me).

  IKE clients MUST ignore any received INTERNAL_DNSSEC_TA requests for
  a FDQN for which it did not receive and accept an INTERNAL_DNS_DOMAIN
  Configuration Payload.

nit: are these really "requests"?

Section 6

It's probably appropriate to reiterate here that "As discussed in Section
5, the INTERNAL_DNSSEC_TA mechanism allows the credential used to
authenticate an IKEv2 association to be leveraged into authenticating
credentials for TLS and other connections.  This reflects something of a
privilege escalation, and initiators should ensure that they have
sufficient trust in the communications peer to responsibly use (or not use)
that elevated privilege."

  If the initiator is using DNSSEC validation for a domain in its
  public DNS view, and it requests and receives an INTERNAL_DNS_DOMAIN
  attribute without an INTERNAL_DNSSEC_TA, it will need to reconfigure
  its DNS resolver to allow for an insecure delegation.  It SHOULD NOT
  accept insecure delegations for domains that are DNSSEC signed in the
  public DNS view, for which it has not explicitely requested such
  deletation by specifying the domain specifically using a
  INTERNAL_DNS_DOMAIN(domain) request.

It seems like heeding this SHOULD NOT would potentially require the
initiator to make extra DNS requests from the external view that it would
not otherwise need to make.  I agree that this is the behavior we want to
encourage with respect to not downgrading away from DNSSEC, but it's less
clear to me that we want to encourage the initiator to go out of its way to
check, as opposed to just using information it may happen to have already.

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

The IANA Functions Operator has completed its review of draft-ietf-ipsecme-split-dns-12. If any part of this review is inaccurate, please let us know.

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

In the IKEv2 Configuration Payload Attribute Types registry on the Internet Key Exchange Version 2 (IKEv2) Parameters registry page located at:

https://www.iana.org/assignments/ikev2-parameters/

the existing registrations

Multi-
Value Attribute Type Valued Length Reference
------ ------------------- ------ ---------- ---------------
25 INTERNAL_DNS_DOMAIN YES 0 or more [current draft]
26 INTERNAL_DNSSEC_TA YES 0 or more [current draft]

will have their references changed to [ RFC-to-be ].

The IANA Functions Operator understands 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.

Thank you,

Sabrina Tanamal
Senior IANA Services Specialist

The following Last Call announcement was sent out (ends 2018-08-24):

From: The IESG
To: IETF-Announce
CC: David Waltermire , ipsecme-chairs@ietf.org, ekr@rtfm.com, ipsec@ietf.org, david.waltermire@nist.gov, draft-ietf-ipsecme-split-dns@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Split DNS Configuration for IKEv2) to Proposed Standard


The IESG has received a request from the IP Security Maintenance and
Extensions WG (ipsecme) to consider the following document: - 'Split DNS
Configuration for IKEv2'
  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
ietf@ietf.org mailing lists by 2018-08-24. 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 two Configuration Payload Attribute Types for
  the IKEv2 protocol that add support for private DNS domains.  These
  domains are intended to be resolved using DNS servers reachable
  through an IPsec connection, while leaving all other DNS resolution
  unchanged.  This approach of resolving a subset of domains using non-
  public DNS servers is referred to as "Split DNS".




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-ipsecme-split-dns/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-ipsecme-split-dns/ballot/


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

As required by RFC 4858, this is the current template for the Document
Shepherd Write-Up.

Changes are expected over time. This version is dated 24 February 2012.

(1) What type of RFC is being requested (BCP, Proposed Standard,
Internet Standard, Informational, Experimental, or Historic)?  Why
is this the proper type of RFC?  Is this type of RFC indicated in the
title page header?

The type of this RFC is Proposed Standard, which is listed in the title page header.

(2) The IESG approval announcement includes a Document Announcement
Write-Up. Please provide such a Document Announcement Write-Up. Recent
examples can be found in the "Action" announcements for approved
documents. The approval announcement contains the following sections:

Technical Summary

  Relevant content can frequently be found in the abstract
  and/or introduction of the document. If not, this may be
  an indication that there are deficiencies in the abstract
  or introduction.

The IPsecME working group has obsoleted the IKEv1 protocol in favor of
the IKEv2 protocol many years ago. However, IKEv2 never had an option
to send one or more DNS domains from a Remote Access VPN server to the
VPN clients. IKEv1 did have that option via XAUTH/ModeCFG.

This document defines two Configuration Payload Attribute Types for
the IKEv2 protocol that add support for private DNS domains.  These
domains are intended to be resolved using DNS servers reachable
through an IPsec connection, while leaving all other DNS resolution
unchanged.  This approach of resolving a subset of domains using non-
public DNS servers is referred to as "Split DNS".

Working Group Summary

  Was there anything in WG process that is worth noting? For
  example, was there controversy about particular points or
  were there decisions where the consensus was particularly
  rough?

The draft had no controversy. The draft has been discussed frequently on
the mailing list and a lot of comments have been provided on list by
people other than the authors, to include implementors. In addition to
mailing list discussions, the draft has been presented and discussed
during the last 3 IETF (98, 99, 100) meetings. The draft has been
supported by the participants in the room on various hums for the
specific design decisions made in the document.
 
Document Quality

  Are there existing implementations of the protocol? Have a
  significant number of vendors indicated their plan to
  implement the specification? Are there any reviewers that
  merit special mention as having done a thorough review,
  e.g., one that resulted in important changes or a
  conclusion that the document had no substantive issues? If
  there was a MIB Doctor, Media Type or other expert review,
  what was its course (briefly)? In the case of a Media Type
  review, on what date was the request posted?

The document is supported by implementors, and authors also represent a
subset of implementors. Interoperability of the DNS domain has been
confirmed by at least three independent implementations. DNSSEC TA
support has not seen an implementation or interoperability test, but
the format is sufficiently simple that no one is worried.
 
Personnel

  Who is the Document Shepherd? Who is the Responsible Area
  Director?

The Document Shepherd is David Waltermire. The responsible Area
Director is Eric Rescorla.
 
(3) Briefly describe the review of this document that was performed by
the Document Shepherd.  If this version of the document is not ready
for publication, please explain why the document is being forwarded to
the IESG.

The document shepherd has completely reviewed this draft to include
review of idnits, the references, and IANA considerations sections. No
issues have been found. The document is ready for publication.
 
(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

The document had a significant number of reviews/comments during the
multiple draft iterations. The document Shepherd believes the document
has been carefully reviewed.

(5) Do portions of the document need review from a particular or from
broader perspective, e.g., security, operational complexity, AAA, DNS,
DHCP, XML, or internationalization? If so, describe the review that
took place.

No.
 
(6) Describe any specific concerns or issues that the Document Shepherd
has with this document that the Responsible Area Director and/or the
IESG should be aware of? For example, perhaps he or she is uncomfortable
with certain parts of the document, or has concerns whether there really
is a need for it. In any event, if the WG has discussed those issues and
has indicated that it still wishes to advance the document, detail those
concerns here.

The document Shepherd has no issue with the document.

(7) Has each author confirmed that any and all appropriate IPR
disclosures required for full conformance with the provisions of BCP 78
and BCP 79 have already been filed. If not, explain why.

The authors confirm there is no IPR disclosure needed.

(8) Has an IPR disclosure been filed that references this document?
If so, summarize any WG discussion and conclusion regarding the IPR
disclosures.

There is no related IPR disclosures for this document, or the prior document, RFC4307.

(9) How solid is the WG consensus behind this document? Does it
represent the strong concurrence of a few individuals, with others
being silent, or does the WG as a whole understand and agree with it? 

The document has been heavily discussed and reviewed by the WG, and has
been presented during the IETF meetings. There has been a significant
number of comments on the draft, which have been sufficiently addressed
by the authors. The document represents the strong consensus of the WG.

(10) Has anyone threatened an appeal or otherwise indicated extreme
discontent? If so, please summarise 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.

(11) Identify any ID nits the Document Shepherd has found in this
document. (See https://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

No error is raised.

== The document seems to lack the recommended RFC 2119 boilerplate, even if
    it appears to use RFC 2119 keywords -- however, there's a paragraph with
    a matching beginning. Boilerplate error?

    (The document does seem to have the reference to RFC 2119 which the
    ID-Checklist requires).

This is caused by the use of RFC8174 boilerplate and should be ignored.
 
(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

The document does not need external formal reviews.

(13) Have all references within this document been identified as
either normative or informative?

Yes.

(14) Are there normative references to documents that are not ready for
advancement or are otherwise in an unclear state? If such normative
references exist, what is the plan for their completion?

No.

(15) Are there downward normative references references (see RFC 3967)?
If so, list these downward references to support the Area Director in
the Last Call procedure.

No.


(16) Will publication of this document change the status of any
existing RFCs? Are those RFCs listed on the title page header, listed
in the abstract, and discussed in the introduction? If the RFCs are not
listed in the Abstract and Introduction, explain why, and point to the
part of the document where the relationship of this document to the
other RFCs is discussed. If this information is not in the document,
explain why the WG considers it unnecessary.

No.

(17) 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 protocol extensions that the document makes
are associated with the appropriate reservations in IANA registries.
Confirm that any referenced IANA registries have been clearly
identified. Confirm that newly created IANA registries include a
detailed specification of the initial contents for the registry, that
allocations procedures for future registrations are defined, and a
reasonable name for the new registry has been suggested (see RFC 5226).

The IANA section adds two new attribute types to the IANA "IKEv2
Configuration Payload Attribute Types" registry. Both of these
entries have been requested for early assignment, have passed expert
review, and already appear in the registry.

(18) List any new IANA registries that require Expert Review for future
allocations. Provide any public guidance that the IESG would find
useful in selecting the IANA Experts for these new registries.

None.

(19) Describe reviews and automated checks performed by the Document
Shepherd to validate sections of the document written in a formal
language, such as XML code, BNF rules, MIB definitions, etc.

There is no need to proceed to further checks.