Security of Messages Exchanged between Servers and Relay Agents
RFC 8213

Received changes through RFC Editor sync (created alias RFC 8213, changed title to 'Security of Messages Exchanged between Servers and Relay Agents', changed abstract to 'The Dynamic Host Configuration Protocol for IPv4 (DHCPv4) has no guidance for how to secure messages exchanged between servers and relay agents.  The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) states that IPsec should be used to secure messages exchanged between servers and relay agents but does not require encryption.  With recent concerns about pervasive monitoring and other attacks, it is appropriate to require securing relay-to-relay and relay-to-server communication for DHCPv6 and relay-to-server communication for DHCPv4.', changed standardization level to Proposed Standard, changed state to RFC, added RFC published event at 2017-08-03, changed IESG state to RFC Published)

[Ballot comment]
Based on e-mail it seems like at least one company is implementing.

Personally, were I voting, I'd vote against making an MTI that I expect almost nobody to follow, but I concede that there's not sufficient evidence of that to hold a discuss here.

[Ballot comment]
Based on e-mail it seems like at least one company is implementing.

Personally, were I voting, I'd vote against making an MTI that I expect almost nobody to follow, but I concede that that's not enough to hold a discuss here.

[Ballot comment]
"This document specifies the optional requirements for relay agent and
  server implementations to support IPsec authentication and encryption
  and recommends operators enable this IPsec support."

Thank you, this adequately addresses my discuss.

[Ballot comment]
I am balloting "Yes", but I share the curiosity about whether people will really do this.

-3, third paragraph: "MUST exchange messages securely"
"Securely" is too ambiguous for a MUST. What specific protections are required?

-3, paragraph 4:
The list starts with no context. A sentence or paragraph describing the purpose of the list would be helpful.

[Ballot comment]
I share the curiosity about whether people will really do this.

-3, third paragraph: "MUST exchange messages securely"
"Securely" is too ambiguous for a MUST. What specific protections are required?

-3, paragraph 4:
The list starts with no context. A sentence or paragraph describing the purpose of the list would be helpful.

[Ballot comment]
Thank you for writing this document.

I am curious to know whether there are existing or planned implementations/deployments of this document.

I am also agreeing with Warren concerns.

[Ballot comment]
Thank you very much for your work on this document.  Once Warren's discuss has been cleared with adequate clarifications and 'updates' text, which I support, this will be a helpful document.  It will be very nice to no longer have the discussion as to why encryption is not required for DHCP, this is a welcome and overdue change. 

Is there an expected change to encrypt the full path in a future revision?

[Ballot comment]
Thank you very much for your work on this document.  Once Warren's discuss has been cleared with adequate clarifications and 'updates' text, which I support, this will be a helpful document.  It will be very nice to no longer have the discussion as to why encryption is not required for DHCP, this is a welcome and overdue change.

[Ballot comment]
I strongly agree with Warren's discuss. This document is an update of RFC3315 and therefore MUST carry the update tag. If someone decides not to implement this new specification, they will still only confirm to RFC3315 and not this new document. As Warren said, someone who wants this encryption needs to require conformance to this new RFC anyway. However I think the IETF should give a clear recommendation here that encryption must be used. If the working group really believes there are cases where encryption is not needed, this document must be rewritten to allow for these cases (by using SHOULD/RECOMMENDED instead of MUST/REQUIRED) and give a clear recommendation when it is acceptable to not use encryption.

Further, I'm also wondering why this is not just incorporated in rfc3315bis?

[Ballot comment]
I strongly agre with Warren's discuss. This document is an update of RFC3315 and therefore MUST carry the update tag. If someone decides not to implement this new specification, they will still only confirm to RFC3315 and not this new document. As Warren said, somesome who wants this encryption needs to require conformance to this new RFC anyway. However I think the IETF should give a clear recommendation here that encryption must be used. If the working group really believes there are cases where encryption is not needed, this document must be rewritten to allow for these cases (by using SHOULD/RECOMMANDED instead of MUST/REQUIRED) and give a clear recomendation when it is acceptable to not use encryption.

Further, I'm also wondering why this is not just incorporated in rfc3315bis?

[Ballot discuss]
This document says that it "replaces the text in RFC3315 Section 21.1.", but it does not have an Updates tag. It is also contains a large blob of RFC3315, with clear explanation of what exactly changed.
The writeup says "Even though this I-D introduces changes to RFC3315, the WG doesn't want to enforce IPsec encryption on every DHCPv6 server. Therefore it does not update RFC3315." -- so, if I'm writing a new DHCPv6 implementation, do I need to support this? The document reads like it tries to update 3315, but the writeup says otherwise -- once published, no-one will read the shepherd writeup. I think that the document itself needs to be clearer that this is an optional extension (so if I want to buy an implementation which does this, I ask for RFC3315 and RFCxxxx).

I also do not understand the relationship between this document (which talks about text RFC3315), and draft-ietf-dhc-rfc3315bis (which is currently in WGLC) -- if rfc3315bis is almost done, should this reference that instead? Or should rfc3315bis simply incorporate this?

[Ballot comment]
I found the document confusing -- it says that it REQUIRES IPsec for DHCPv4 and DHCPv6, but it reads like it is requiring that operators enable this, not that implementations have to support this; what exactly is is trying to do?
I think that it would be much clearer if it said that implementations of this document must support IPsec and that operators are recommended to enable it (assuming that it what it means).

[Ballot discuss]
What's not clear to me from reading this docment is whether anyone
actually does IPsec for DHCP relaying. If so, what configurations do
they run it in? If not, will they do so as the result of this
document?

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

The IANA Services Operator has reviewed [draft-enter-here], 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.

Thank you,

Sabrina Tanamal
IANA Services Specialist
PTI

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC: tomasz.mrugalski@gmail.com, dhc-chairs@ietf.org, suresh.krishnan@ericsson.com, draft-ietf-dhc-relay-server-security@ietf.org, Tomek Mrugalski , dhcwg@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Security of Messages Exchanged Between Servers and Relay Agents) to Proposed Standard


The IESG has received a request from the Dynamic Host Configuration WG
(dhc) to consider the following document:
- 'Security of Messages Exchanged Between Servers and Relay Agents'
  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 2017-03-13. 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


  The Dynamic Host Configuration Protocol for IPv4 (DHCPv4) has no
  guidance for how to secure messages exchanged between servers and
  relay agents.  The Dynamic Host Configuration Protocol for IPv6
  (DHCPv6) states that IPsec should be used to secure messages
  exchanged between servers and relay agents, but does not require
  encryption.  And, with recent concerns about pervasive monitoring and
  other attacks, it is appropriate to require securing relay to relay
  and relay to server communication for DHCPv6 and relay to server
  communication for DHCPv4.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-dhc-relay-server-security/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-dhc-relay-server-security/ballot/


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

Write-up for draft-ietf-dhc-relay-server-security-02

(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?

  Standards track. This I-D clarifies how DHCPv4 and DHCPv6 traffic between
  servers and relays should be protected and uses normative language.
  Therefore this is the right type. The intended type is clearly
  indicated in the 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

  DHCPv4 has no guidance for how to secure messages exchanged between
  servers and relay agents. The DHCPv6 states that IPsec should be
  used to secure messages exchanged between servers and relay agents,
  but does not require encryption.  And, with recent concerns about
  pervasive monitoring and other attacks, it is appropriate to
  require securing relay to relay and relay to server communication
  for DHCPv4 and DHCPv6. This draft codifies how to use IPsec with
  encryption to secure that communication.

Working Group Summary

  This draft was created as a result of a concern raised by during
  IESG review of draft-ietf-dhc-access-network-identifier (https://
  mailarchive.ietf.org/arch/msg/dhcwg/17b2yzdJOS1hif95kRIQXidudI8).
  The issue was the DHCP options could reveal user identifying
  information when a client communicates with a server via
  relay(s). This was a generic DHCP issue, so the decision was made to
  write a separate draft. Using IPsec for that purpose seems to be an
  obvious choice and that is what the draft proposes.

  This draft was first presented in Buenos Aires (April 2016) and
  later in Berlin (July 2016) and got unanimous support in the room on
  both occasions. It was adopted in Sep. 2016. The draft is very short
  (a bit over 2 pages of actual content) and changed very little
  between its first individual revision and the rev that passed
  WGLC. That is understandable, as it codifies the obvious solution
  implied by RFC3315 and was written by two experienced engineers (one
  of them being DHC co-chair). This is also the reason why this draft
  received fewer comments than average. In total, there were 37
  messages related to this draft posted to DHC list and a handful more
  circulated off the list.

Document Quality

  This document is of high quality. The reviews it received my seem
  like not too thorough, but that's because of the draft's shortness
  and a high quality of its initial version. The authors are two
  experienced DHCP engineers working for Cisco. I have personally
  reviewed -01 rev of this draft had some minor comments. They were
  addressed in -02.

Personnel

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

  Tomek Mrugalski is the shepherd. Suresh Krishnan is the responsible AD.

(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.

  I reviewed the document before its adoption.  I thoroughly reviewed
  this document second time during WGLC (-01):
  https://mailarchive.ietf.org/arch/msg/dhcwg/s7ipaeaePK1ht3OSk0hxx683V9A
  The minor issues I pointed out were addressed properly. This
  document is ready for publication in my opinion.

(4) Does the document Shepherd have any concerns about the depth or
breadth of the reviews that have been performed?

  No, at least not from the DHCP perspective. An extra review from
  security experts would be welcome. Ops-dir feedback would be
  probably be useful, too.

(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.

  This I-D is DHCP-centric, so DHC is the proper WG for this work. It
  would be useful to have sec-dir review of it.  This draft was
  reviewed by Stephen Farrell on Oct. 14, 2016, but sadly his (brief)
  comments were sent off the list, so the review is not well
  documented. I was part of that discussion. I confirmed that
  Stephen's comment was addressed in -01.

(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.

  I have no such concerns, except asking for a sec-dir review and
  optionally ops-dir review.

(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.

  Yes, both authors confirmed in writing. There are no IPRs, existing or
  outstanding.

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

  No.

(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 consensus is pretty solid. There was an unanimous nod of
  approval in the room when it was presented. Usage of IPsec with
  encryption is the obvious choice and some deployments are already
  doing it. Sadly, not a lot of people thought it is important enough
  to confirm their approval on the ML. That's probably because RFC3315
  indicated that already and that's what people typically do when they
  need to secure their relay-server communication.

(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 http://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

  There are 3 idnit comments and all of them are not a problem. First,
  the draft uses pre-RFC5378 disclaimer, because it contains text from
  RFC3315 (which we know some of the authors are not reachable).

  Second is the publication year not matching current. Yes, it was
  published in 2016 and that is stated correctly.

  The third nit is for outdated reference (sedhcpv6-18, with -20 being
  available). This will be fixed by RFC Editor. Sedhcpv6 authors are
  eager to update their draft as soon as any comments arrive (11
  revisions in the last 13 months), so trying to keep up would be a
  waste of time.

(12) Describe how the document meets any required formal review
criteria, such as the MIB Doctor, media type, and URI type reviews.

  No such review is required.

(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. All normative references are to published RFCs only.

(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. There are no such references.

(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. Even though this I-D introduces changes to RFC3315, the WG doesn't
  want to enforce IPsec encryption on every DHCPv6 server. Therefore
  it does not update RFC3315.

(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).

  This document does not require any IANA actions. That is clearly
  stated in the IANA considerations section.

(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.

  There are no such registries defined.

(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 are no such sections, so automated checks are not necessary.