Host Address Availability Recommendations
draft-ietf-v6ops-host-addr-availability-07

[Ballot comment]

I have followed the discussion between Roni Even (Gen-ART reviewer) and Lorenzo:

> The intent here is to say that while the DHCPv6 PD RFC uses the words
> "requesting router" to denote the DHCP client, is nothing in DHCPv6 PD
> itself that requires the PD client to be a router (where, in IPv6, the term
> "router" is defined in RFC2460).

> So - even though the DHCPv6 PD RFC uses the term "requesting router", a
> host can use DHCPv6 PD to receive a prefix as well. The host can pick some
> addresses for that prefix for its own use, originate/terminate packets on
> those addresses, and not forward packets addressed to any of the other
> addresses in the prefix.

Personally, I think it would perhaps useful to consider a slight reformulation of the text, given that for things like tethering or virtual machines, hosts essentially become routers.

[Ballot comment]

(I'm getting a bit outside my area of expertise here, but
since I've been playing about with IPv6 recently and am not
shy about asking silly questions... :-)

- I think you're missing one other reason why people
allocate /128's - in a hosting/VPS environment, the hoster
might want to avoid VPS's that originate spam using many
different source addresses over time so as to attempt to
avoid IP address based (bad) reputation accruing to their
outbound spam. Personally, I think associating such
reputation scores with IPv6 prefixes or addresses is a bit
dodgy, but this is I think something that is done in the
wild, (no idea how frequently) so would be worth a mention.
If you have good arguments as to why such a scheme is a bad
idea, that'd be good to include as well.

- I was a bit surprised to not see any mention here of
ULAs. I've seen one DHCPv6 setup where my laptop was
assigned a ULA with a very long lease in the hope of always
having that connectivity to local systems that aren't all
on the link. But having that plus real global addresses
caused glitches as (I think) my OS (ubuntu) wasn't sure
which of the addresses to use as the source for what.
While I didn't explore what was going on there (I just
zapped the lease:-), do you need to say how to handle cases
where one has both real global and ULAs on an interface?

- I would have liked if you had said that, other things
being equal, OSes SHOULD prefer to use privacy addresses as
the source address or as a default. Is there a reason to
not say that? (Just wondering, I'm not trying to strongly
argue that you do.)

[Ballot comment]
Section 3:

* What is the term ePDG being used here? Can you please add a reference? The well known term in mobile networks is Evolved Packet Data Gateway that is used for IPsec tunnel termination. That does not seem to make sense here.

* Maybe worth adding a reference to RFC7278 (64share) here as an example for "Extending the network (e.g., "tethering")."

s/which is only available in 3GPP release 10/which is only available in 3GPP release 10 onwards/

Section 4:

It is not clear what this bullet means. Can you clarify?

"  o  Uncertainty, because it is not known in advance if a particular
      operation function will be available."

[Ballot comment]
While I am afraid the NAT66 cats are forever out of their bag, I am still glad to see this draft.

Section 7: I _think_ the point of this section is to suggest that we cannot reasonably estimate an upper limit. But if it says that explicitly, I missed it. (I fear a careless reader will walk away thinking "20" is a good limit)

Section 8: s/RECOMMENDED to not impose a hard limit/NOT RECOMMENDED to impose a hard limit/

[Ballot comment]
I think the Complexity mentioned in section 4 should be a security consideration since there are more opportunities for mistakes that lead to data leakage.

[Ballot comment]
Section 3: s/which is only available in 3GPP release 10/which has been made available as of 3GPP release 10/

Section 9.1:
- May be better not to presume that operators do things "to avoid liability" - I don't think that particular sentence is necessary here.
- I was surprised not to see a note here about interaction between this kind of host tracking and MAC address randomization, which I assume makes tracking harder independently of the whether the recommendations in this document are followed. But is it not discussed because operators who feel they need these kind of logs also prohibit MAC randomization?

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

IANA has reviewed draft-ietf-v6ops-host-addr-availability-05.txt, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any IANA 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, IANA does not object.

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

Thank you,

Sabrina Tanamal
IANA Specialist
ICANN

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: v6ops@ietf.org, fred.baker@cisco.com, draft-ietf-v6ops-host-addr-availability@ietf.org, joelja@gmail.com, v6ops-chairs@ietf.org, draft-ietf-v6ops-host-addr-availability.all@tools.ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Host address availability recommendations) to Best Current Practice


The IESG has received a request from the IPv6 Operations WG (v6ops) to
consider the following document:
- 'Host address availability recommendations'
  as Best Current
Practice

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 2016-03-09. 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 recommends that networks provide general-purpose end
  hosts with multiple global IPv6 addresses when they attach, and
  describes the benefits of and the options for doing so.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-v6ops-host-addr-availability/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-v6ops-host-addr-availability/ballot/


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

(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 title page, and working group discussion, requests BCP status.

(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

  This document recommends that networks provide general-purpose end
  hosts with multiple global IPv6 addresses when they attach, and
  describes the benefits of and the options for doing so.

Working Group Summary

  This particular draft has not been controversial; it borders on
  stating the obvious, and certainly states a consensus of IPv6
  operators and designers in the IETF. It does, however, recommend
  a change from current general practice with DHCP/DHCPv6,
  a change that the author's companies are explicitly exploring and
  finding useful, which is to allocate a prefix to a host rather than
  a single address.

Document Quality

  This is not a protocol, it is a proposal regarding IPv6 protocol
  deployment practice. That said, yes, there are multiple implementations.
  Windows, MacOSX, Linux, and other operating systems expect to use
  multiple addresses in the same prefix simultaneously, and common
  practice using SLAAC directly supports this. The issue has to do with
  DHCP/DHCPv6 address allocation, which a network operator might restrict
  to a single address unnecessarily.

Personnel

  The Document Shepherd is Fred Baker.
  The AD is Joel Jaegli.

(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.

  When the initial draft was posted (July 2015), I read it and suggested to
  the working group that this might express an existing consensus and
  be worth simply sending in. There was discussion, which I followed.
  I have read versions 4 and 5 of the draft, and agree with its comments.

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

  No

(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.

  I don't think it needs review, per se, but it would be worth ensuring
  that the DHCP Working Group is aware of it, as the topic may affect
  their thinking. The draft mentions DHCP-PD deployment to a host, as
  opposed to to a network, which is being experimented with in multiple
  scenarios and discussed in the IETF. NVO3 may also be interested.

(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 am comfortable with the document and its recommendations.

(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.

(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? 

  I would describe the consensus behind this document as "very solid".

(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.

  In section 9.2, the draft comments on the use of RFC 1918 addresses
  in IPv4 networks, and specifically mentions two of those prefixes.
  The mention is accurate.
 
  The "security considerations" section could be described as "minimal".
  That said, the statement is accurate: no security considerations
  have been identified.

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

  It doesn't need that.

(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).

  There are no requests made to IANA, and that is stated to be the case.

(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.

  None.