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Domain Name System Operations                               J. Livingood
Internet-Draft                                                   Comcast
Intended status: Informational                              C. Griffiths
Expires: March 28, 2015                                              Dyn
                                                      September 24, 2014


          Definition and Use of DNSSEC Negative Trust Anchors
               draft-livingood-negative-trust-anchors-07

Abstract

   DNS Security Extensions (DNSSEC) is now entering widespread
   deployment.  However, domain signing tools and processes are not yet
   as mature and reliable as is the case for non-DNSSEC-related domain
   administration tools and processes.  One potential technique to
   mitigate this is to use a Negative Trust Anchor, which is defined in
   this document.

   This document discusses Trust Anchors for DNSSEC and defines a
   Negative Trust Anchor, which is potentially useful during the
   transition to ubiquitous DNSSEC deployment.  These are configured
   locally on a particular instance of a validating DNS recursive
   resolver and can shield end users of such a resolver from the DNSSEC-
   related authoritative name server operational errors that appear to
   be somewhat typical during the transition to ubiquitous DNSSEC
   deployment.  Negative Trust Anchors are intended to be temporary, and
   should not be distributed by IANA or any other organization outside
   of the administrative boundary of the organization locally
   implementing a Negative Trust Anchor.  Finally, Negative Trust
   Anchors pertain only to DNSSEC and not to Public Key Infrastructures
   (PKI) such ad X.509.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."




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   This Internet-Draft will expire on March 28, 2015.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Definition of a Negative Trust Anchor . . . . . . . . . . . .   4
   3.  Limited Time and Scope of Use . . . . . . . . . . . . . . . .   4
   4.  Domain Validation Failures  . . . . . . . . . . . . . . . . .   5
   5.  End User Reaction . . . . . . . . . . . . . . . . . . . . . .   5
   6.  Switching to a Non-Validating Resolver is Not Recommended . .   6
   7.  Responsibility for Failures . . . . . . . . . . . . . . . . .   6
   8.  Use of a Negative Trust Anchor  . . . . . . . . . . . . . . .   7
   9.  Managing Negative Trust Anchors . . . . . . . . . . . . . . .   8
   10. Removal of a Negative Trust Anchor  . . . . . . . . . . . . .   9
   11. Comparison to Other DNS Misconfigurations . . . . . . . . . .   9
   12. Intentionally Broken Domains  . . . . . . . . . . . . . . . .  10
   13. Other Considerations  . . . . . . . . . . . . . . . . . . . .  10
     13.1.  Security Considerations  . . . . . . . . . . . . . . . .  10
     13.2.  Privacy Considerations . . . . . . . . . . . . . . . . .  11
     13.3.  IANA Considerations  . . . . . . . . . . . . . . . . . .  11
   14. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   15. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     15.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     15.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Appendix A.  Document Change Log  . . . . . . . . . . . . . . . .  13
   Appendix B.  Open Issues  . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   The Domain Name System (DNS), DNS Security Extensions (DNSSEC), and
   related operational practices are defined extensively [RFC1034]




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   [RFC1035] [RFC4033] [RFC4034] [RFC4035] [RFC4398] [RFC4509] [RFC6781]
   [RFC5155].

   This document discusses Trust Anchors for DNSSEC and defines a
   Negative Trust Anchor, which is potentially useful during the
   transition to ubiquitous DNSSEC deployment.  These are configured
   locally on a particular instance of a validating DNS recursive
   resolver and can shield end users of such a resolver from the DNSSEC-
   related authoritative name server operational errors that appear to
   be somewhat typical during the transition to ubiquitous DNSSEC
   deployment.  Negative Trust Anchors are intended to be temporary, and
   should not be distributed by IANA or any other organization outside
   of the administrative boundary of the organization locally
   implementing a Negative Trust Anchor.  Finally, Negative Trust
   Anchors pertain only to DNSSEC and not to Public Key Infrastructures
   (PKI) such ad X.509.  [REFERENCE NECESSARY?]

   DNSSEC has now entered widespread deployment.  However, domain
   signing tools and processes are not yet as mature and reliable as is
   the case for non-DNSSEC-related domain administration tools and
   processes.  As a result, operators of DNS recursive resolvers, such
   as Internet Service Providers (ISPs), occasionally observe domains
   incorrectly managing DNSSEC-related resource records.  This
   mismanagement triggers DNSSEC validation failures, and then causes
   large numbers of end users to be unable to reach a domain.  Many end
   users tend interpret this as a failure of their DNS servers, and may
   switch to a non-validating resolver or contact their ISP to complain,
   rather than seeing this as a failure on the part of the domain they
   wanted to reach.

   In the short-term, one potential way to address this is for DNS
   operators to use a Negative Trust Anchor to temporarily disable
   DNSSEC validation for a specific misconfigured domain name.  This
   immediately restores access for end users while that domain's
   administrators fix their misconfiguration.  While DNS operators
   likely prefer not to use this tool, during the global transition to
   DNSSEC it seems some tool is needed to reduce the negative impact on
   such operators.

   A Negative Trust Anchor should be considered a transitional and
   temporary tactic which is not particularly scalable and should not be
   used in the long-term.  Over time, however, the use of Negative Trust
   Anchors will become less necessary as DNSSEC-related domain
   administration becomes more resilient.







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2.  Definition of a Negative Trust Anchor

   Trust Anchors are defined in [RFC5914].  A trust anchor should be
   used by a validating caching resolver as a starting point for
   building the authentication chain for a signed DNS response.  The
   inverse of this is a Negative Trust Anchor, which creates a stopping
   point for a caching resolver to end validation of the authentication
   chain.  This Negative Trust Anchor can potentially be placed at any
   level within the chain of trust and would stop validation at that
   point in the chain.

3.  Limited Time and Scope of Use

   As noted in Section 1, the use of Negative Trust Anchors should be
   temporary.  These are key recommendations pertaining to this
   practice:

   1.  The general practice of using Negative Trust Anchors should be
       limited to the transition to widespread deployment of DNSSEC
       (including signing of domain names and validation in DNS
       recursive resolvers).  Thus, the practice of using Negative Trust
       Anchors should not be permanent.

   2.  During this transition phase when Negative Trust Anchors may be
       useful, the use of a particular Negative Trust Anchor should be
       temporary and in most cases limited to no more than 1 day.  Thus,
       the use of an individual Negative Trust Anchor should be strictly
       time limited and very short in duration.

   3.  So that the use of Negative Trust Anchors remains temporary and
       useful only during a transition to widespread DNSSEC deployment,
       the use and distribution of individual Negative Trust Anchors
       should not be centralized, beyond the borders of one
       organization's operational unit.  Thus, no organization should
       endeavor to create and centrally distribute Negative Trust
       Anchors to other organizations as was the case with positive
       Trust Anchors prior to the signing of the root.

   4.  As noted in Section 12, organizations that utilize Negative Trust
       Anchors should not add a Negative Trust Anchor for any
       intentionally broken domain.

   5.  As noted in Section 8, use of a Negative Trust Anchor should not
       be automatic in any way, and must involve investigation by
       technical personnel trained in the operation of DNS servers.






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4.  Domain Validation Failures

   A domain name can fail validation for two general reasons, a
   legitimate security failure such as due to an attack or compromise of
   some sort, or as a result of misconfiguration on the part of an
   domain administrator.  As domains transition to DNSSEC the most
   likely reason for a validation failure will be due to
   misconfiguration.  Thus, domain administrators should be sure to read
   [RFC6781] in full.  They should also pay special attention to
   Section 4.2, pertaining to key rollovers, which appears to be the
   cause of many recent validation failures.

   In one recent example [DNSSEC-Validation-Failure-Analysis], a
   specific domain name failed to validate.  An investigation revealed
   that the domain's administrators performed a Key Signing Key (KSK)
   rollover by (1) generating a new key and (2) signing the domain with
   the new key.  However, they did not use a double-signing procedure
   for the KSK and a pre-publish procedure for the ZSK.  Double-signing
   refers to signing a zone with two KSKs and then updating the parent
   zone with the new DS record so that both keys are valid at the same
   time.  This meant that the domain name was signed with the new KSK,
   but it was not double-signed with the old KSK.  So, the new key was
   used for signing the zone but the old key was not.  As a result, the
   domain could not be trusted and returned an error when trying to
   reach the domain.  Thus, the domain was in a situation where the
   DNSSEC chain of trust was broken because the Delegation Signer (DS)
   record pointed to the old KSK, which was no longer used for signing
   the zone.  (A DS record provides a link in the chain of trust for
   DNSSEC from the parent zone to the child zone - in this case between
   TLD and domain name.)

   In addition, it is possible that some DNSSEC validation failures
   could arise due to differences in how different software developers
   interpret DNSSEC standards and/or how those developers choose to
   implement support for DNSSEC.  For example, it is conceivable that
   some domain may be DNSSEC signed properly, and Unbound-based DNS
   recursive resolvers will validate the domain but those using BIND or
   Nominum's Vantio software may fail to validate a domain.

5.  End User Reaction

   End users generally do not know what DNSSEC is, nor should they be
   expected to at the current time (especially absent widespread
   integration of DNSSEC indicators in end user software such as web
   browsers).  As a result, end users may incorrectly interpret the
   failure to reach a domain due to DNSSEC-related misconfiguration as
   their ISP purposely blocking access to the domain or as a performance
   failure on the part of their ISP (especially of the ISP's DNS



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   servers).  End users may feel less satisfied with their ISP's
   service, which may make them more likely to switch to a competing
   ISP.  They may also contact their ISP to complain, which of course
   will incur cost for their ISP.  In addition, they may use online
   tools and sites to complain of this problem, such as via a blog, web
   forum, or social media site, which may lead to dissatisfaction on the
   part of other end users or general criticism of an ISP or operator of
   a DNS recursive resolver.

   As end users publicize these failures, others may recommend they
   switch from security-aware DNS resolvers to resolvers not performing
   DNSSEC validation.  This is a shame since the ISP or other DNS
   recursive resolver operator is actually doing exactly what they are
   supposed to do in failing to resolve a domain name, as this is the
   expected result when a domain can no longer be validated, protecting
   end users from a potential security threat.

6.  Switching to a Non-Validating Resolver is Not Recommended

   As noted in Section 5 some people may consider switching to an
   alternative, non-validating resolver themselves, or may recommend
   that others do so.  But if a domain fails DNSSEC validation and is
   inaccessible, this could very well be due to a security-related
   issue.  In order to be as safe and secure as possible, end users
   should not change to DNS servers that do not perform DNSSEC
   validation as a workaround, and people should not recommend that
   others do so either.  Even if a website in a domain seems to look
   "normal" and valid, according to the DNSSEC protocol, that domain is
   not secure.  Domains that fail DNSSEC for legitimate reasons may be
   in control of hackers or there could be other significant security
   issues with the domain.

   Thus, switching to a non-validating resolver to restore access to a
   domain that fails DNSSEC validation is not a recommended practice, is
   bad advice to others, is potentially harmful to end user security,
   and is potentially harmful to DNSSEC adoption.

7.  Responsibility for Failures

   A domain administrator is solely and completely responsible for
   managing their domain name(s) and DNS resource records.  This
   includes complete responsibility for the correctness of those
   resource records, the proper functioning of their DNS authoritative
   servers, and the correctness of DNS records linking their domain to a
   top-level domain (TLD) or other higher level domain.  Even in cases
   where some error may be introduced by a third party, whether that is
   due to an authoritative server software vendor, software tools
   vendor, domain name registrar, or other organization, these are all



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   parties that the domain administrator has selected and is responsible
   for managing successfully.

   There are some cases where the domain administrator is different than
   the domain owner.  In those cases, a domain owner has delegated
   operational responsibility to the domain administrator.  So no matter
   whether a domain owner is also the domain administrator or not, the
   domain administrator is nevertheless operationally responsible for
   the proper configuration operation of the domain.

   So in the case of a domain name failing to successfully validate,
   when this is due to a misconfiguration of the domain, that is the
   sole responsibility of the domain administrator.

   Any assistance or mitigation responses undertaken by other parties to
   mitigate the misconfiguration of a domain name by a domain
   administrator, especially operators of DNS recursive resolvers, are
   optional and at the pleasure of those parties.

8.  Use of a Negative Trust Anchor

   When a domain has been confirmed to fail DNSSEC validation due to a
   DNSSEC-related misconfiguration, an ISP or other DNS recursive
   resolver operator may in some cases use a Negative Trust Anchor for a
   domain or sub-domain.  This instructs a DNS recursive resolver to
   temporarily NOT perform DNSSEC validation for a specific domain name.
   This immediately restores access to the domain for end users while
   the domain's administrator corrects the misconfiguration(s).

   In the case of a validation failure due to misconfiguration of a TLD
   or popular domain name (such as a top 100 website), this could make
   content or services in the affected TLD or domain to be inaccessible
   for a large number of users.  A Negative Trust Anchor can therefore
   be useful in the short-term when used on a targeted and time-limited
   basis.  It does not and should not involve turning off validation
   more broadly, and helps during the transition to DNSSEC as
   organizations that are new to signing their domains are still
   maturing their DNSSEC operational practices, alleviating end user
   issues as noted in Section 5 and restoring end user access.  However,
   use of a Negative Trust Anchor should not be automatic in any way,
   and must involve investigation by technical personnel trained in the
   operation of DNS servers.

   Technical personnel should also confirm that the domain is not
   intentionally broken, such as for testing purposes as noted in
   Section 12.  Such an investigation must confirm that a failure is due
   to misconfiguration, as a similar breakage could have occurred if an
   attacker gained access to a domain's authoritative servers and



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   modified those records or had the domain pointed to their own rogue
   authoritative servers.  In addition, personnel should make a
   reasonable attempt to contact a domain for which a Negative Trust
   Anchor may be used, and preferably prior to implementing it.

   Furthermore, a Negative Trust Anchor MUST only be used for a short
   duration, such as for a day or less.  Implementors SHOULD set an end
   time and date associated with any Negative Trust Anchor.
   Implementors SHOULD in most cases limit the maximum duration to one
   day, meaning the Negative Trust Anchor will be removed or invalidated
   from the point of implementation, plus 86,400 seconds.  However,
   there may be corner cases where a Negative Trust Anchor is needed for
   a longer period of time.  Optimally this time and date is set in a
   DNS recursive resolver's configuration, though in the short-term this
   may also be achieved via other systems or supporting processes.

   Finally, a Negative Trust Anchor is used only in a specific domain or
   sub-domain and would not affect validation at other names up the
   authentication chain.  For example, a Negative Trust Anchor for
   zone1.example.com would affect only names within zone1.example.com,
   and validation would still be performed on example.com, .com, and the
   root (".").  In another example, a Negative Trust Anchor for
   example.com would affect only names within example.com, and
   validation would still be performed on .com, and the root (".")

      Root (.)              <======
          |                       ||
          |                       ||<======>+----+----+     DNSSEC
          |                       ||        |Recursive|    Validation
      TLD (com)             <=====||        |Resolver | <==============>
          |                        +<------>+---------+
          |                        |                       DNS NTA
          |                        |                 (zone1.example.com)
  SUB TLD (example.com)     <------|                    <-------------->
          |                        |
          |                        |
          |                        |
          (zone1.example.com <-----|

                  Figure 1: Negative Trust Anchor Diagram

9.  Managing Negative Trust Anchors

   This tool is unlikely to be and probably should not be used over the
   long-term since DNSSEC-related domain administration practices will
   naturally improve over time.  In addition, however, continued and
   frequent use of Negative Trust Anchors is not scalable since it
   requires investigation by technical personnel and may involve manual



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   processes, resulting in increased operational overhead (and therefore
   cost).

   While Negative Trust Anchors have proven useful during the early
   stages of DNSSEC adoption, domain owners are ultimately responsible
   for managing and ensuring their DNS records are configured correctly
   Section 7.

   Most current implementations of DNS validating resolvers currently
   follow [RFC4033] on defining the implementation of Trust Anchor as
   either using Delegation Signer (DS), Key Signing Key (KSK), or Zone
   Signing Key (ZSK).  A Negative Trust Anchor should use domain name
   formatting that signifies where in a delegation a validation process
   should be stopped.

   Different DNS recursive resolvers may have different configuration
   names for a Negative Trust Anchor.  For example, Unbound calls their
   configuration "domain-insecure" [Unbound-Configuration]

10.  Removal of a Negative Trust Anchor

   As explored in Section 13.1, if a Negative Trust Anchor is still in
   place after the point in time when the DNS misconfiguration that
   caused validation to break has been fixed, this could be problematic.
   It is therefore recommended that implementors should periodically or
   even continuously attempt to validate the domain in question, for the
   period of time that the Negative Trust Anchor is in place, until such
   validation is again successful.  (Obviously a Negative Trust Anchor
   could be removed prior to validation succeeding again, alleviating an
   implementor of the need to continuing to test validation separate
   from their normal operations.)

   Once validation is again successful, a Negative Trust Anchor should
   be removed as soon as is reasonably possible.  Optimally this is
   automatic, though it may also be achieved via other systems or
   supporting processes.

11.  Comparison to Other DNS Misconfigurations

   As noted in Section 7 domain administrators are ultimately
   responsible for managing and ensuring their DNS records are
   configured correctly.  ISPs or other DNS recursive resolver operators
   cannot and should not correct misconfigured A, CNAME, MX, or other
   resource records of domains for which they are not authoritative.
   Expecting non-authoritative entities to protect domain administrators
   from any misconfiguration of resource records is therefore
   unrealistic and unreasonable, and in the long-term is harmful to the




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   delegated design of the DNS and could lead to extensive operational
   instability and/or variation.

12.  Intentionally Broken Domains

   Some domains, such as dnssec-failed.org, have been intentionally
   broken for testing purposes
   [Measuring-DNSSEC-Validation-of-Website-Visitors] [Netalyzr].  For
   example, dnssec-failed.org is a DNSSEC-signed domain that is broken.
   If an end user is querying a validating DNS recursive resolver, then
   this or other similarly intentionally broken domains should fail to
   resolve and should result in a SERVFAIL error.  If such a domain
   resolved successfully, then it is a sign that the DNS recursive
   resolver is not fully validating.

   Organizations that utilize Negative Trust Anchors should not add a
   Negative Trust Anchor for any intentionally broken domain.

   Organizations operating an intentionally broken domain may wish to
   consider adding a TXT record for the domain to the effect of "This
   domain is purposely DNSSEC broken for testing purposes".

13.  Other Considerations

13.1.  Security Considerations

   End to end DNSSEC validation will be disabled during the time that a
   Negative Trust Anchor is used.  In addition, the Negative Trust
   Anchor may be in place after the point in time when the DNS
   misconfiguration that caused validation to break has been fixed.
   Thus, there may be a gap between when a domain has have been re-
   secured and when a Negative Trust Anchor is removed.  In addition, a
   Negative Trust Anchor may be put in place by DNS recursive resolver
   operators without the knowledge of the authoritative domain
   administrator for a given domain name.

   End users of a DNS recursive resolver or other people may wonder why
   a domain that fails DNSSEC validation resolves with a supposedly
   validating resolver.  As a result, implementors should consider
   transparently disclosing those Negative Trust Anchors which are
   currently in place or were in place in the past, such as on a website
   [Disclosure-Example].  This is particularly important since there is
   currently no special DNS query response code that could indicate to
   end users or applications that a Negative Trust Anchor is in place.
   Such disclosures should optimally include both the data and time that
   the Negative Trust Anchor was put in place and when it was removed.





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13.2.  Privacy Considerations

   There are no privacy considerations in this document.

13.3.  IANA Considerations

   There are no IANA considerations in this document.

14.  Acknowledgements

   Several people made contributions of text to this document and/or
   played an important role in the development and evolution of this
   document.  This in some cases included performing a detailed review
   of this document and then providing feedback and constructive
   criticism for future revisions, or engaging in a healthy debate over
   the subject of the document.  All of this was helpful and therefore
   the following individuals merit acknowledgement:

   - Joe Abley

   - John Barnitz

   - Tom Creighton

   - Marco Davids

   - Brian Dickson

   - Patrik Falstrom

   - Tony Finch

   - Chris Ganster

   - Olafur Gudmundsson

   - Peter Hagopian

   - Wes Hardaker

   - Paul Hoffman

   - Shane Kerr

   - Murray Kucherawy

   - Warren Kumari




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   - Rick Lamb

   - Marc Lampo

   - Ted Lemon

   - Ed Lewis

   - Antoin Verschuren

   - Paul Vixie

   - Patrik Wallstrom

   - Nick Weaver

   - Ralf Weber

15.  References

15.1.  Normative References

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, November 1987.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, November 1987.

   [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "DNS Security Introduction and Requirements", RFC
              4033, March 2005.

   [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Resource Records for the DNS Security Extensions",
              RFC 4034, March 2005.

   [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Protocol Modifications for the DNS Security
              Extensions", RFC 4035, March 2005.

   [RFC4398]  Josefsson, S., "Storing Certificates in the Domain Name
              System (DNS)", RFC 4398, March 2006.

   [RFC4509]  Hardaker, W., "Use of SHA-256 in DNSSEC Delegation Signer
              (DS) Resource Records (RRs)", RFC 4509, May 2006.






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   [RFC5155]  Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
              Security (DNSSEC) Hashed Authenticated Denial of
              Existence", RFC 5155, March 2008.

   [RFC5914]  Housley, R., Ashmore, S., and C. Wallace, "Trust Anchor
              Format", RFC 5914, June 2010.

   [RFC6781]  Kolkman, O., Mekking, W., and R. Gieben, "DNSSEC
              Operational Practices, Version 2", RFC 6781, December
              2012.

15.2.  Informative References

   [DNSSEC-Validation-Failure-Analysis]
              Barnitz, J., Creighton, T., Ganster, C., Griffiths, C.,
              and J. Livingood, "Analysis of DNSSEC Validation Failure -
              NASA.GOV", Comcast , January 2012,
              <http://www.dnssec.comcast.net/
              DNSSEC_Validation_Failure_NASAGOV_20120118_FINAL.pdf>.

   [Disclosure-Example]
              Comcast, "faa.gov Failing DNSSEC Validation (Fixed)",
              Comcast , February 2013,
              <http://dns.comcast.net/index.php/entry/
              faa-gov-failing-dnssec-validation-fixed>.

   [Measuring-DNSSEC-Validation-of-Website-Visitors]
              Mens, J., "Is my Web site being used via a DNSSEC-
              validator?", July 2012, <http://jpmens.net/2012/07/30/
              is-my-web-site-being-used-via-dnssec-validator/>.

   [Netalyzr]
              Weaver, N., Kreibich, C., Nechaev, B., and V. Paxson,
              "Implications of Netalyzr's DNS Measurements", Securing
              and Trusting Internet Names, SATIN 2011 SATIN 2011, April
              2011, <http://conferences.npl.co.uk/satin/presentations/
              satin2011slides-Weaver.pdf>.

   [Unbound-Configuration]
              Wijngaards, W., "Unbound: How to Turn Off DNSSEC", June
              2010, <http://unbound.net/documentation/
              howto_turnoff_dnssec.html>.

Appendix A.  Document Change Log

   [RFC Editor: This section is to be removed before publication]

   -00: First version published as an individual draft.



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   -01: Fixed minor typos and grammatical nits.  Closed all open
   editorial items.

   -02: Simple date change to keep doc from expiring.  Substantive
   updates planned.

   -03: Changes to address feedback from Paul Vixie, by adding a new
   section "Limited Time and Scope of Use".  Changes to address issues
   raised by Antoin Verschuren and Patrik Wallstrom, by adding a new
   section "Intentionally Broken Domains" and added two related
   references.  Added text to address the need for manual investigation,
   as suggested by Patrik Falstrom.  Added a suggestion on notification
   as suggested by Marc Lampo.  Made several additions and changes
   suggested by Ralf Weber, Wes Hardaker, Nick Weaver, Tony Finch, Shane
   Kerr, Joe Abley, Murray Kucherawy, Olafur Gudmundsson.

   -04: Moved the section defining a NTA forward, and added new text to
   the Abstract and Introduction per feedback from Paul Hoffman.

   -05: Incorporated feedback from the DNSOP WG list received on 2/17/13
   and 2/18/13.  This is likely the final version before the IETF 86
   draft cutoff date.  Updated references to RFC6781 to RFC6781, per
   March Davids.

   -06: Added more OPEN issues to continue tracking WG discussion.  No
   changes in the main document - just expanded issue tracking.

   -07: Refresh document - needs revision and rework before IETF-91.
   Planning to add more contributors.

Appendix B.  Open Issues

   [RFC Editor: This section is to be removed before publication]

   Determine whether RFC 2119 language should be used or not when
   describing things like the duration of a NTA.

   The DNSOP WG should discuss whether a 1 day limit is reasonable,
   whether a different time (more or less than 1 day, such as 1 hour or
   1 week) should be specified, or whether no time should be specified
   (just a recommendation that it SHOULD generally be limited to X).

   Olafur Gudmundsson has suggested that we may want to consider whether
   a non validatable RRSIG should be returned or not when a NTA is in
   place.  This was raised in the context of NLnet Labs' DNSSEC-Trigger,
   which apparently acts like forwarding stub-validator.  He said, "The
   reason for this is if NTA strips signatures the stub-validator thinks
   it is under attack and may a) go into recursive mode to try to



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   resolve the domain, getting to the right answer the long way. b) Give
   the wrong error "Missing signatures" instead of the real error.  If
   all the validator does is not to set the AD bit for RRsets at and
   below the NTA, stub-resolvers (and cascading resolvers) should be
   happy."

   Determine whether an informative reference to X.509 in the
   Introduction is necessary.

   Is it desirable to say that NTAs should not be distributed across
   organizational boundaries?

   Per Warren Kumari on 2/19/2013, add examples to appendix. "it would
   be very helpful to actually show how this is used, with e.g and
   example in an Appendix, for -insert favorite resolver here-. The
   document contains a lot of really useful content about why you might
   use one, how to minimize damage, etc but (IMO) does't do a great job
   of explaining how to actually do so".  Rick Lamb and Joe Abley also
   agreed on the need for this.

   Per Rick Lamb on 2/20/2013, "it might be useful to have section 2
   "Definition .." make that clear for slow people like me - that the
   NTA is not an RR and is more of a configuration.  Maybe simply
   replacing "placed" with "implemented" in section 2?  "This NTA can
   potentially be -placed/implemented- at any level within the chain of
   trust"

   Per Olafur Gudmundsson on 2/18/2013, address fact that ALL
   authoritative name servers must be working. "section 10 you talk
   about possible early removal the NTA when validation succeeds but
   there may be instances where validation succeeds when using a sub-set
   of the authoritative servers thus NTA should only be removed if all
   servers are providing "good" signatures."

   Per Olafur Gudmundsson on 2/18/2013, "Furthermore what to do if some
   names work but others do not, for example I remember a case where the
   records at the apex worked but all names below the apex were signed
   by a key not in the DNSKEY RRset, thus it is possible that either
   human or automated checks may assume there is no problem when there
   actually is one.  What this is bringing to my mind is maybe you want
   a new section with guidelines on how to test for failures and in what
   cases failure justifies NTA and what tests MUST pass before
   preemttive removal of an NTA."

   Per Olafur Gudmundsson on 2/18/2013, "Also should there be guidance
   that removal of NTA should include cleaning the caches of all RRsets
   below the name?"




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   Reference and text per Ed Lewis: One thing that seems to need
   repeating from time to time is this passage in RFC 4033.  ... In the
   final analysis, however, authenticating both DNS keys and data is a
   matter of local policy, which may extend or even override the
   protocol extensions defined in this document set.  See Section 5 for
   further discussion.  A responsibility (one of many) of a caching
   server operator is to "protect the integrity of the cache."  DNSSEC
   is just a tool to help accomplish that.  It carries ancillary data
   that a local cache administrator may use to filter out undesired
   responses.  DNSSEC is not an enforcement mechanism, it's a resource.
   When I see folks voice opinions that DNSSEC's recommended operation
   has to strictly followed, my gut reaction is that these folks have
   forgotten the purpose of all of our efforts.  We don't secure
   protocols to make things work better.  We don't operate the DNS
   because we like to run a well run machine.  We don't run the Internet
   for the fun of it.  (Some might enjoy running it, that's job
   satisfaction to some extent.)  At the end of the day all that matters
   is that what is being done benefits society.  We run the Internet to
   enrich society.  We prefer a well run DNS because it saps less
   resources than a poorly run DNS.  We prefer secure protocols so that
   people don't become victims (in some sense of the word).  Make it
   work.  Do what it takes to make it work.  "Local policy" rules.

   Per David Conrad: I'd suggest that in the BCP/RFC/whatever, in
   addition to recommending that NTAs be time capped and not written to
   permanent storage, it should also recommend NTAs be written as
   specifically as possible.  (Should be obvious, but doesn't hurt to
   reiterate I suppose).

   Per Ralf Weber: Informing the domain owner on the validation failure.
   There should be a section in the document that the operator deploying
   an NTA has to inform the domain owner of the problem.  (JL note:
   would prefer to say operator SHOULD take reasonable steps to notify
   the domain owner, etc.)

Authors' Addresses

   Jason Livingood
   Comcast Cable Communications
   One Comcast Center
   1701 John F. Kennedy Boulevard
   Philadelphia, PA  19103
   US

   Email: jason_livingood@cable.comcast.com
   URI:   http://www.comcast.com





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   Chris Griffiths
   Dyn

















































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