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Versions: 00 01 02 03

Network Working Group                                          W. Kumari
Internet-Draft                                                    Google
Updates: 6304 (if approved)                                 W. Sotomayor
Intended status: Informational                                  NRC-CNRC
Expires: August 29, 2013                                        J. Abley
                                                                   ICANN
                                                               R. Bellis
                                                              Nominet UK
                                                       February 25, 2013


                        Omniscient AS112 Servers
                draft-wkumari-dnsop-omniscient-as112-02

Abstract

   The AS112 Project loosely coordinates Domain Name System (DNS)
   servers to which DNS zones corresponding to private use addresses are
   delegated.  Queries for names within those zones have no useful
   responses in a global context.  The purpose of this project is to
   reduce the load of such junk queries on the authoritative name
   servers that would otherwise receive them, and instead direct the
   load to name servers operated within the AS112 project.

   Adding and dropping zones from the AS112 servers is difficult, due to
   the loosely-coordinated nature of the project.  This document
   proposes a mechanism by which AS112 name servers could answer
   authoritatively for all possible zones.  This eliminates the add/drop
   problem, changing it to a matter of delegation within the DNS and
   requiring no operational changes on the servers themselves.

   This document updates RFC 6304.

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 August 29, 2013.

Copyright Notice

   Copyright (c) 2013 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
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



































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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  Protocol Considerations  . . . . . . . . . . . . . . . . . . .  5
   4.  Operational Considerations . . . . . . . . . . . . . . . . . .  6
   5.  Addressing Considerations  . . . . . . . . . . . . . . . . . .  7
   6.  Updates to RFC 6304  . . . . . . . . . . . . . . . . . . . . .  7
     6.1.  Changes to Section 3.4, Routing Software . . . . . . . . .  7
     6.2.  Changes to Section 3.5, DNS Software . . . . . . . . . . .  9
     6.3.  Changes to Section 3.6, Testing a Newly Installed Node . .  9
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  9
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . .  9
   9.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 10
     10.2. Informative References . . . . . . . . . . . . . . . . . . 10
   Appendix A.  Implementation / "Running Code" . . . . . . . . . . . 10
   Appendix B.  Document Notes  . . . . . . . . . . . . . . . . . . . 11
     B.1.  Venue  . . . . . . . . . . . . . . . . . . . . . . . . . . 11
     B.2.  Textual Substitutions  . . . . . . . . . . . . . . . . . . 11
     B.3.  Open Questions . . . . . . . . . . . . . . . . . . . . . . 11
     B.4.  Change History . . . . . . . . . . . . . . . . . . . . . . 11
       B.4.1.  draft-wkumari-dnsop-omniscient-as112-00  . . . . . . . 12
       B.4.2.  draft-wkumari-omniscient-as112-00  . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13

























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1.  Introduction

   The AS112 Project loosely coordinates Domain Name System (DNS)
   servers [RFC1034] to which DNS zones corresponding to private use
   addresses are delegated.  Queries for names within those zones have
   no useful responses in a global context.  The purpose of the project
   is to reduce the load of such junk queries on the authoritative name
   servers that would otherwise receive them, directing the load instead
   to name servers operated within the AS112 project.

   To date, AS112 nameservers have been used exclusively for names
   corresponding to the reverse mapping for private-use IPv4 addresses.
   A description of current advice for AS112 operators, including
   motivations and guidance for technical deployment and operations can
   be found in [RFC6304].

   Other DNS domains have analogously local significance.  Examples
   corresponding to the reverse-mapping of special-use IPv4 and IPv6
   addresses can be found in [RFC6303].

   It is to be expected that new domains will be identified from time to
   time that fit the use pattern for which delegation to AS112 servers
   might be desirable.  There is currently no mechanism by which
   particular zones can be reliably added to or dropped from AS112
   servers, however.  This is principally a consequence of the loosely-
   coordinated nature of the project, coupled with a desire to avoid
   lame delegations which might have unforeseen operational
   consequences.

   This document proposes a mechanism by which AS112 servers could
   provide consistent, reliable negative responses for all DNS queries,
   eliminating the operational requirement to add or drop particular
   zones from all AS112 servers.


2.  Terminology

   An "Existing AS112 Server" is a DNS name server configured according
   to the guidance provided in [RFC6304] and listening on the IPv4
   addresses 192.175.48.1 (PRISONER.IANA.ORG), 192.175.48.6 (BLACKHOLE-
   1.IANA.ORG) and 192.175.48.42 (BLACKHOLE-2.IANA.ORG).

   An "Omniscient AS112 Server" is a DNS nameserver configured according
   to the guidance provided in [RFC6304], as extended by this document.
   Such servers listen on the same addresses as Existing AS112 Servers,
   but also additional addresses as described in Section 5.

   Where discussions apply equally to Existing AS112 Servers and



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   Omniscient AS112 Servers, the unqualified phrase "AS112 Server" is
   used.

   An "AS112 Zone" is a DNS zone which has been delegated to an AS112
   Server.

   An "Existing AS112 Zone" is an AS112 Zone which has been delegated to
   an existing AS112 Server.


3.  Protocol Considerations

   Familiarity with [RFC1034] and [RFC1035] is assumed.

   In order to safely cache the response, DNS implementations require
   the closest-enclosing SOA to be returned.  An omniscient AS112 server
   (which is not configured with a specific list of zones, and hence
   zone cuts) cannot necessarily know where that is.  Removing labels
   and guessing (whether to the extreme case of removing all labels, or
   returning one, or anything in between) cannot be guaranteed to be
   appropriate, since the answers might clash with authentic answers
   already present in client caches.  A client that has followed a
   referral to an omniscient AS112 server is guaranteed not to have a
   cached SOA that matches the QNAME, however, so Omniscient AS112
   servers use the QNAME as the SOA and owner name.

   Please see Appendix A for information on an implementation ("running
   code") that does this.

   AS112 Servers do not respond to AXFR (QTYPE=252) or IXFR (QTYPE=251)
   requests.

   A TYPE=6 (SOA) resource record for Omniscient AS112 servers contains:
   o  MNAME = "a.as112.net."
   o  RNAME = "hostmaster.as112.net."
   o  SERIAL = 1
   o  REFRESH =604800 (7 days)
   o  RETRY = 2592000 (30 days)
   o  EXPIRE = 604800 (7 days)
   o  MINIMUM = 604800 (7 days, negative caching TTL)

   For all queries with QTYPE=2 (NS) an AS112 Server responds with an
   authoritative (AA=1) answer with NXDomain (RCODE=3), the owner name
   copied from the QNAME and two resource records of TYPE=2 (NS), one
   containing "B.AS112.NET." and the containing "C.AS112.NET.".

   For all queries with QTYPE=6 (SOA) an AS112 Server responds with an
   authoritative (AA=1) answer with NXDomain (RCODE=3), the owner name



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   copied from the QNAME and one (ANCOUNT=1) resource record of TYPE=6
   (SOA).

   For all queries with QTYPE= 255 (*, also known as ANY) an AS112
   Server responds with an authoritative (AA=1) answer with NXDomain
   (RCODE=3) the owner name copied from the QNAME and three (ANCOUNT=3)
   resource records, one containing the SOA (as described above), and
   two containing NS (also as described above).

   For all other queries an AS112 Server responds with an authoritative
   (AA=1) NoError (RCODE=0) with the owner name copied from the QNAME in
   the request and no answers (ANCOUNT=0).  The resource record of
   TYPE=6 (SOA) (as described above) should be returned in the authority
   section.  The presence of the SOA is to allow the negative cache TTL
   to be set(see [RFC2308]).


4.  Operational Considerations

   Existing AS112 Servers address the protocol considerations described
   in Section 3 by serving each existing AS112 Zone explicitly.  In each
   case the zone contents are identical, containing only required apex
   SOA and NS records.  Adding or dropping a delegation for an Existing
   AS112 Zone requires coordination amongst all deployed Existing AS112
   Server operators.

   There is no practical expectation that AS112 Server operators
   coordinate the configuration of their infrastructure or even make
   their existence known in any systematic way.  Delegation of new zones
   to Existing AS112 Servers is hence problematic; there is an
   expectation that such delegations would be lame for a significant
   client population.  Since the predictable behaviour of AS112 Servers
   from clients is desirable, and it is possible that significant
   variation would have operational consequences, no new zones should be
   delegated to existing AS112 Servers.

   Omniscient AS112 Servers generate a response (as described in
   Section3 (Section 3)) as though they are authoritative for everything
   (".").  Adding or dropping a delegation for an AS112 Zone therefore
   imposes no operational requirements on Omniscient AS112 Server
   operators.

   Delegation of new AS112 Zones should only be made to Omniscient AS112
   Servers.  Omniscient AS112 Servers, therefore, must listen on
   additional addresses to those used by existing AS112 Servers.
   Addressing is discussed in Section 5.

   By ensuring that Omniscient AS112 Servers listen on Existing AS112



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   Servers' addresses as well as the new addresses specified in
   Section 5 a smooth migration is possible, allowing Existing AS112
   Servers to be reconfigured as Omniscient AS112 Servers.  Omniscient
   AS112 Servers are therefore a superset of AS112 Servers.


5.  Addressing Considerations

   Omniscient AS112 Servers listen on the following addresses:

   o  IPv4-TBA1 (A.AS112.NET)
   o  IPv6-TBA1 (A.AS112.NET)
   o  IPv4-TBA2 (B.AS112.NET)
   o  IPv6-TBA2 (B.AS112.NET)
   o  IPv4-TBA3 (C.AS112.NET)
   o  IPv6-TBA3 (C.AS112.NET)

   IPv4-TBA1, IPv4-TBA2 and IPv4-TBA3 are covered by a single IPv4
   prefix, IPv4-PREFIX-TBA.  Similarly, IPv6-TBA1, IPv6-TBA2 and IPv6-
   TBA3 are covered by a single IPv6 prefix, IPv6-PREFIX-TBA.

   The addresses specified for Omniscient AS112 Servers are deliberately
   different from those assigned to Existing AS112 Servers for reasons
   discussed in Section 4.


6.  Updates to RFC 6304

6.1.  Changes to Section 3.4, Routing Software

   Omniscient AS112 Nodes with IPv4 connectivity should originate the
   IPv4 service prefix associated with Existing AS112 Nodes,
   192.175.48.0/24, and also the IPv4 service prefix associated with
   Omniscient AS112 Nodes, IPv4-PREFIX.

   Omniscient AS112 Nodes with IPv6 connectivity should originate the
   IPv6 service prefix IPv6-PREFIX-TBA.

   Applying this direction to the "bgpd.conf" file included as an
   example in this section results in the configuration shown in
   Figure 1.

      ! bgpd.conf
      !
      hostname as112-bgpd
      password <something>
      enable password <supersomething>
      !



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      ! Note that all AS112 nodes use the local Autonomous System
      ! Number 112, and originate IPv4 and IPv6 prefixes (where IPv4
      ! and IPv6 connectivity is available) as follows:
      !
      !   IPv4:  192.175.48.0/24
      !          IPv4-PREFIX-TBA
      !
      !   IPv6:  IPv6-PREFIX-TBA
      !
      ! All other addresses shown below are illustrative, and
      ! actual numbers will depend on local circumstances.
      !
      router bgp 112
       bgp router-id 203.0.113.1
       !
       address-family ipv4
         network 192.175.48.0
         neighbor 192.0.2.1 remote-as 64496
         neighbor 192.0.2.1 next-hop-self
         neighbor 192.0.2.1 prefix-list AS112-v4 out
         neighbor 192.0.2.1 filter-list 1 out
         neighbor 192.0.2.2 remote-as 64497
         neighbor 192.0.2.2 next-hop-self
         neighbor 192.0.2.2 prefix-list AS112-v4 out
         neighbor 192.0.2.2 filter-list 1 out
         network 192.175.48.0/24
         network IPv4-PREFIX-TBA
       !
       address-family ipv6 unicast
         neighbor 2001:db8::1 remote-as 64496
         neighbor 2001:db8::1 next-hop-self
         neighbor 2001:db8::1 prefix-list AS112-v6 out
         neighbor 2001:db8::1 filter-list 1 out
         neighbor 2001:db8::2 remote-as 64497
         neighbor 2001:db8::2 next-hop-self
         neighbor 2001:db8::2 prefix-list AS112-v6 out
         neighbor 2001:db8::2 filter-list 1 out
         network IPv6-PREFIX-TBA
      !
      ip prefix-list AS112-v4 permit 192.175.48.0/24
      ip prefix-list AS112-v4 permit IPv4-PREFIX-TBA
      !
      ipv6 prefix-list AS112-v6 permit IPv6-PREFIX-TBA
      !
      ip as-path access-list 1 permit ^$

                                 Figure 1




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6.2.  Changes to Section 3.5, DNS Software

   Omniscient AS112 Servers should be configured to listen on the
   addresses Pv6-TBA1, IPv6-TBA, IPv6-TBA3, IPv4-TBA1, IPv4-TBA2 and
   IPv4-TBA3 in addition to the addresses used for Existing AS112
   Servers.

   Omniscient AS112 Servers generate an answer as described in Section 3
   instead of explicitly serving the zones specified in [RFC6304].

   As ISC BIND [BIND] does not provide the required functionality a
   custom nameserver implementation needs to be deployed, and so the
   example "named.conf" file in this section can be disregarded.

6.3.  Changes to Section 3.6, Testing a Newly Installed Node

   Testing should include all configured service addresses for an
   Omniscient AS112 Server (IPv4 or IPv6 or both, as appropriate).  Note
   that the IPv4 service addresses include those described in [RFC6304]
   for Existing AS112 Servers.


7.  IANA Considerations

   This document describes infrastructure which could be used in the
   future to direct the IANA to delegate or redelegate infrastructure
   zones under its administrative control.

   However, this document makes no request of the IANA.


8.  Security Considerations

   The contents of the Security Considerations section of [RFC6304]
   should be reviewed, since that discussion is pertinent to the
   operation of Omniscient AS112 Servers as well as Existing AS112
   Servers.

   The deployment of Omniscient AS112 Servers enables new delegations to
   AS112 Servers.

   Queries received by an AS112 Server might reveal operational data for
   which there is an expectation of privacy.  For example, leaked
   queries for an organisation's internal DNS names which are sent to an
   AS112 Server might reveal the existence of those names to the AS112
   Server operator.  The delegation of new zones to AS112 Servers has
   the potential to increase opportunities for such unintentional
   information leakage.



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   The delegation of new zones to AS112 Servers has the potential to
   increase the traffic received by those servers.  AS112 Server
   operators are encouraged to monitor traffic levels, and to take
   appropriate steps if traffic levels threaten the stability of their
   networks.


9.  Acknowledgements

   The authors thank and acknowledge the contributions of Dr Paul Vixie,
   Bill Manning, George Michaelson, Mark Andrews, Shane Kerr, Brian
   Dickson, S. Moonesamy, Chris Thompson, Nick Hilliard and all the folk
   on the AS112 Project mailing lists in the preparation of this
   document.


10.  References

10.1.  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.

   [RFC2308]  Andrews, M., "Negative Caching of DNS Queries (DNS
              NCACHE)", RFC 2308, March 1998.

   [RFC6304]  Abley, J. and W. Maton, "AS112 Nameserver Operations",
              RFC 6304, July 2011.

10.2.  Informative References

   [BIND]     Nominet UK, "Internet Systems Consortium, "BIND"",
              <http://www.isc.org/>.

   [RFC6303]  Andrews, M., "Locally Served DNS Zones", BCP 163,
              RFC 6303, July 2011.

   [evldns]   Bellis, R., "evldns", <http://code.google.com/p/evldns/>.


Appendix A.  Implementation / "Running Code"

   The "evldns" [evldns] library (written by Ray Bellis, Nominet UK)
   includes an Omniscient AS112 Server implementation in the file
   "oas112d.c"



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Appendix B.  Document Notes

   This section (and sub-sections) contain information useful for
   development and review of this document, and should be removed prior
   to publication.

B.1.  Venue

   This document is an individual submission, and is not the product of
   an IETF working group.  However, a suitable venue for discussion is
   the dnsop working group mailing list.

B.2.  Textual Substitutions

   The strings "IPv4-TBA1", "IPv4-TBA2" and "IPv4-TBA3" should be
   replaced in this document should be replaced with IPv4 addresses
   assigned for the purpose described.  The covering IPv4 prefix for all
   three addresses should replace the string "IPv4-PREFIX-TBA".

   Similarly, the strings "IPv6-TBA1", "IPv6-TBA2", "IPv6-TBA3" and
   "IPv6-PREFIX-TBA" should be substituted in the text with assigned
   production values.

B.3.  Open Questions

   1.  Where to get IPv4 and IPv6 assignments from?  There has already
       been an assignment to DNS-OARC by ARIN for v6 service for AS112
       servers.

B.4.  Change History

   Template:

   o  Initial draft
   o  Initial draft, circulated privately, not submitted.

   -00:

   o  Rewrote much of the document (especially Section 3 to explain how
      (and why) resonses should be generated.
   o  Updated "Updates to RFC 6304" section to explain the BIND does not
      currently implement this, and so named.conf, etc should be
      ignored.
   o  Removed example "empty" zone.
   o  Changed the addressing bit at the suggestion of SM.

   -01:




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   o  Document title changed to include the dnsop keyword, so that IETF
      document automation can send courtesy notifications of document
      actions to the dnsop working group.
   o  Abstract and introduction expanded.
   o  RFC2119 requirements notation removed, since this is an
      informational document and any normative language would be
      toothless.
   o  Discussion broken out into Protocol Considerations, Operational
      Considerations and Addressing Considerations.
   o  Reverted to the custom sowftware / synthesized answers.
   o  Added in the Ray Bellis evldns stuff.

   -01 to -02:

   o  s/NoError/NXDomain/ -- Suggestion from Paul Vixie (and others).
      "Nxd says there is no such name, no matter what the type was, and
      there are no children.  No data/noerror says there are either
      other types or children or both.  We know what the truth must be
      and we know which implications we want the requestor to follow.
      Right?" -- Paul.
   o  Need to retest with empty root zone, and "minimal responses".
      Initial test didn't seem to suppress the 'Negative Answers from
      Authoritative Servers' (rfc2308)
   o  Removed the ''Editor note: [NoError was chosen instead of NXDOMAIN
      because we did not think that we could reasonably return an SOA RR
      which clearly indicates that the QNAME does exist, and also return
      an NXDOMAIN.]" as we are now using NXDomain :-P
   o  This version submitted by Warren, with no real discussion with co-
      authors.  Trying to squeeze things under the -01 cutoff.

B.4.1.  draft-wkumari-dnsop-omniscient-as112-00

   Document title changed to include the dnsop keyword, so that IETF
   document automation can send courtesy notifications of document
   actions to the dnsop working group.

   Abstract and introduction expanded.

   RFC2119 requirements notation removed, since this is an informational
   document and any normative language would be toothless.

   Discussion broken out into Protocol Considerations, Operational
   Considerations and Addressing Considerations.

   Detailed updates to [RFC6304] added.






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B.4.2.  draft-wkumari-omniscient-as112-00


Authors' Addresses

   Warren Kumari
   Google
   1600 Ampitheatre Parkway
   Mountain View, CA  94043
   USA

   Email: warren@kumari.net


   William F. Maton Sotomayor
   National Research Council of Canada
   1200 Montreal Road
   Ottawa, ON  K1A 0R6
   Canada

   Phone: +1 613 993 0880
   Email: wfms@ryouko.imsb.nrc.ca


   Joe Abley
   ICANN
   12025 Waterfront Drive, Suite 300
   Los Angeles, CA  90094-2536
   USA

   Phone: +1 519 670 9327
   Email: joe.abley@icann.org


   Ray Bellis
   Nominet UK
   Edmund Halley Road
   Oxford,   OX4 4DQ
   United Kingdom

   Phone: +44 1865 332211
   Email: ray.bellis@nominet.org.uk









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