Operational Neighbor Discovery Problems
draft-ietf-v6ops-v6nd-problems-05

[Ballot comment]
I have no objection to the publication of this document.

It discusses a problem that is very close to the problem that we have chartered the ARMD  to address and I am wondering whether there needs to be a reference to that work.

[Ballot comment]
This document sure feels like a standards-track Applicability Statement to me. Did the WG consider requesting a status of Proposed Standard?

Please consider citing RFC 4732 at the first use of the term Denial of Service.

[Ballot comment]
I have no objeciton to the publication of this document, but I noticed
a few small points I hope you will look at before publication.

---

While appreciating the desire to use RFCs to force vendors to provide
specific function to the operators, I don't think that the use of
RFC 2119 language in this Informational document adds very much (the
language is intended to add clarity to protocol specifiations, and is
sometimes used to make requirements documents clearer). In fact, I
cold only find two uses of such language (both are "SHOULD") in this
document so I suggest you change them to normal lower case, and drop
the boilerplate from Section 1.

---

Section 4

  During testing it was concluded that 4 simultaneous
  nmap sessions from a low-end computer was sufficient to make a
  router's neighbor discovery process unusable and therefore forwarding
  became unavailable to the destination subnets.

Without casting aspertions on the authors, is it possible to provide
some qualification of this statement? For example, a reference to the
test description and results, or a simple note as to by whom the testing
was carried out.

Similarly...

  The failure to maintain proper NDP behavior whilst under attack has
  been observed across multiple platforms and implementations,
  including the largest modern router platforms available (at the
  inception of work on this document).

... would benefit from a reference.

---

Section 6

s/stipulated/suggested/ or s/stipulated/stated/

---

Section 7 might benefit from more detail on the management interfaces
that operators would like to see provided by vendors both for the
control of the optional mechanisms discussed in this document and for
the notification about and analysis of attacks.

---

It might have been nice to add a note about the interaction with
mobility (such as of VMs in a data center).

State changed to In Last Call from Last Call Requested.

The following Last Call Announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Subject: Last Call:  (Operational Neighbor Discovery Problems) to Informational RFC


The IESG has received a request from the IPv6 Operations WG (v6ops) to
consider the following document:
- 'Operational Neighbor Discovery Problems'
  as an Informational RFC

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 2012-02-20. 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


  In IPv4, subnets are generally small, made just large enough to cover
  the actual number of machines on the subnet.  In contrast, the
  default IPv6 subnet size is a /64, a number so large it covers
  trillions of addresses, the overwhelming number of which will be
  unassigned.  Consequently, simplistic implementations of Neighbor
  Discovery (ND) can be vulnerable to deliberate or accidental denial
  of service, whereby they attempt to perform address resolution for
  large numbers of unassigned addresses.  Such denial of attacks can be
  launched intentionally (by an attacker), or result from legitimate
  operational tools or accident conditions.  As a result of these
  vulnerabilities, new devices may not be able to "join" a network, it
  may be impossible to establish new IPv6 flows, and existing IPv6
  transported flows may be interrupted.

  This document describes the potential for DOS in detail and suggests
  possible implementation improvements as well as operational
  mitigation techniques that can in some cases be used to protect
  against or at least alleviate the impact of such attacks.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-v6ops-v6nd-problems/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-v6ops-v6nd-problems/


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

(1.a) Who is the Document Shepherd for this document? Has the
Document Shepherd personally reviewed this version of the
document and, in particular, does he or she believe this
version is ready for forwarding to the IESG for publication?

The document shepherd is Fred Baker. Yes, I believe that it is ready for IESG consideration. A related (solution) draft is under discussion in 6man:

http://datatracker.ietf.org/doc/draft-gashinsky-6man-v6nd-enhance
http://tools.ietf.org/html/draft-gashinsky-6man-v6nd-enhance
"Neighbor Discovery Enhancements for DOS mititgation", Warren Kumari,
8-Jan-12

(1.b) Has the document had adequate review both from key WG members
and from key non-WG members? Does the Document Shepherd have
any concerns about the depth or breadth of the reviews that
have been performed?

Yes. I was discussed in v6ops at IETF 81 and 82. The original draft discussed the problem and a proposed solution; this draft is simply the problem statement

(1.c) Does the Document Shepherd have concerns that the document
needs more review from a particular or broader perspective,
e.g., security, operational complexity, someone familiar with
AAA, internationalization or XML?

No. The solution may call for wider review, but not the problem statement.

(1.d) Does the Document Shepherd have any specific concerns or
issues 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. Has an IPR disclosure related to this document
been filed? If so, please include a reference to the
disclosure and summarize the WG discussion and conclusion on
this issue.

No.

(1.e) 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?

Yes. We had numerous review comments, mostly of the form (to quote Randy Bush) "I like".

(1.f) 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
entered into the ID Tracker.)

No.

(1.g) Has the Document Shepherd personally verified that the
document satisfies all ID nits? (See the Internet-Drafts Checklist
and http://tools.ietf.org/tools/idnits/). Boilerplate checks are
not enough; this check needs to be thorough. Has the document
met all formal review criteria it needs to, such as the MIB
Doctor, media type and URI type reviews?

yes.

(1.h) Has the document split its references into normative and
informative?

yes.

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
strategy for their completion? Are there normative references
that are downward references, as described in [RFC3967]? If
so, list these downward references to support the Area
Director in the Last Call procedure for them [RFC3967].

the normative references are all RFCs.

(1.i) Has the Document Shepherd verified that the document IANA
consideration section exists and is consistent with the body
of the document?

yes.

(1.j) Has the Document Shepherd verified that sections of the
document that are written in a formal language, such as XML
code, BNF rules, MIB definitions, etc., validate correctly in
an automated checker?

there are none.

(1.k) 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

In IPv4, subnets are generally small, made just large enough to cover
the actual number of machines on the subnet. In contrast, the
default IPv6 subnet size is a /64, a number so large it covers
trillions of addresses, the overwhelming number of which will be
unassigned. Consequently, simplistic implementations of Neighbor
Discovery can be vulnerable to deliberate or accidental denial of
service, whereby they attempt to perform address resolution for large
numbers of unassigned addresses. Such denial of attacks can be
launched intentionally (by an attacker), or result from legitimate
operational tools or accident conditions. As a result of these
vulnerabilities, new devices may not be able to "join" a network, it
may be impossible to establish new IPv6 flows, and existing IPv6
transported flows may be interrupted.

This document describes the potential for DOS in detail and suggests
possible implementation improvements as well as operational
mitigation techniques that can in some cases be used to protect
against or at least alleviate the impact of such attacks.

Working Group Summary

The topic was discussed in v6ops, with essentially smooth consensus supporting the document.

Document Quality

This is a problem statement. As such, one doesn't expect an implementation...