Decreasing Access Time to Root Servers by Running One on Loopback
draft-wkumari-dnsop-root-loopback-01

The information below is for an old version of the document
Document Type Active Internet-Draft (individual)
Authors Warren Kumari  , Paul Hoffman 
Last updated 2014-11-11
Replaced by draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, draft-ietf-dnsop-root-loopback, RFC 7706, RFC 7706, RFC 7706
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Network Working Group                                          W. Kumari
Internet-Draft                                                    Google
Intended status: Informational                                P. Hoffman
Expires: May 15, 2015                                     VPN Consortium
                                                       November 11, 2014

   Decreasing Access Time to Root Servers by Running One on Loopback
                  draft-wkumari-dnsop-root-loopback-01

Abstract

   Some DNS recursive resolvers have longer-than-desired round trip
   times to the closest DNS root server.  Such resolvers can greatly
   decrease the round trip time by running a copy of the full root zone
   on a loopback address (such as 127.0.0.1).  This document shows how
   to start and maintain such a copy of the root zone in a manner that
   is secure for the operator of the recursive resolver and does not
   pose a threat to other users of the DNS.

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on May 15, 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
   to this document.  Code Components extracted from this document must

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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
     1.1.  Requirements Notation . . . . . . . . . . . . . . . . . .   3
   2.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Operation of the Root Zone on the Loopback Address  . . . . .   3
   4.  Using the Root Zone Server on the Loopback Address  . . . . .   4
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Appendix A.  Current Sources of the Root Zone . . . . . . . . . .   5
   Appendix B.  Example Configurations of Common Implementations . .   5
     B.1.  Example Configuration: BIND 9.9 . . . . . . . . . . . . .   5
     B.2.  Example Configuration: Unbound 1.4 and NSD 4  . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   DNS recursive resolvers have to answer all queries from their
   customers, even those which are for domain names that do not exist.
   For each queried name that has a top level domain (TLD) that is not
   in the recursive resolver's cache, the resolver must send a query to
   a root server to get the information for that TLD, or to find out
   that the TLD does not exist.  If there is a slow path between the
   recursive resolver and the closest root server, getting slow
   responses to these queries has a negative effect on the resolver's
   customers.

   This document describes a method for the operator of a recursive
   resolver to greatly speed these queries.  The basic idea is to create
   an up-to-date root zone server on a loopback address on the same host
   as the recursive server, and that server is used when the recursive
   resolver uses for looking up root information.  The recursive
   resolver validates all responses from the root server on the loopback
   address, just as it would all responses from a remote root server.

   The primary goal of this design is to provide faster negative
   responses to stub resolver queries that contain junk queries.  This
   design will probably have little effect on getting faster positive
   responses to stub resolver for good queries on TLDs, because the data
   for those zones is usually long-lived and already in the cache of the
   recursive resolver; thus, getting faster positive responses is a non-
   goal of this design.

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   This design explicitly only allows the new root zone server to be run
   on a loopback address.  This prevents the server from serving
   authoritative answers to any system other than the recursive
   resolver.

   This design requires the addition of authoritative name server
   software running on the same machine as the recursive resolver.
   Thus, recursive resolver software such as BIND will not need to add
   much new functionality, but recursive resolver software such as
   Unbound will need to be able to talk to an authoritative server (such
   as NSD) running on the same host.

1.1.  Requirements Notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

2.  Requirements

   In the discussion below, the term "legacy operation" means the way
   that a recursive resolver acts when it is not using the mechanism
   describe in this document, namely as a normal validating recursive
   resolver with no other special features.

   In order to implement the mechanism described in this document:

   o  The system MUST be able to validate a zone with DNSSEC.

   o  The system MUST have an up-to-date copy of the DNS root key.

   o  The system MUST be able to retrieve a copy of the entire root zone
      (including all DNSSEC-related records).

   o  The system MUST be able to run an authoritative server on one of
      the IPv4 loopback addresses (that is, an address in the range
      127/8).

3.  Operation of the Root Zone on the Loopback Address

   The operation of an authoritative server for the root in the system
   described here can be done separately from the operation of the
   recursive resolver.

   The steps to set up the root zone are:

   1.  Retrieve a copy of the root zone.  (See Appendix A for some
       current locations of sources.)

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   2.  Start the authoritative server with the root zone on a loopback
       address that is not in use.  This would typically be 127.0.0.1,
       but if that address is in use, any address in 127/8 is
       acceptable.

   The contents of the root zone must be refreshed using the timers from
   the SOA record in root zone, as described in [RFC1035].  If the
   contents of the zone cannot be refreshed before the expire time, the
   server MUST return a SERVFAIL error response for all queries until
   the zone can be successfully be set up again.

4.  Using the Root Zone Server on the Loopback Address

   A recursive resolver that wants to use a root zone server operating
   as described in Section 3 simply specifies the local address as the
   place to look when it is looking for information from the root.  All
   responses from the rootserver on localhost must be validated using
   DNSSEC.

   Note that using this configuration will cause the recursive resolver
   to fail if the local root zone server fails.

5.  IANA Considerations

   This document requires no action from the IANA.

6.  Security Considerations

   A system that does not follow the DNSSEC-related requirements given
   in Section 2 can be fooled into giving bad responses in the same way
   as any recursive resolver that does not do DNSSEC validation on
   responses from a remote root server.

7.  Acknowledgements

   The editors fully acknowledge that this is not a new concept, and
   that we have chatted with many people about this.  In fact, this
   concept may already have been implemented without the knowledge of
   the authors.  For example, Bill Manning described something similar
   in his doctoral dissertation in 2013.

   Evan Hunt contributed greatly by finding some flaws in the logic in
   the -00 draft, and by offering a BIND configuration that works with
   the requirements.

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8.  Normative References

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

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

Appendix A.  Current Sources of the Root Zone

   The root zone can be retrieved from anywhere as long as it comes with
   all the DNSSEC records needed for validation.  Currently, there are
   three sources of the root zone supported by ICANN:

   o  From ICANN via FTP at ftp://rs.internic.net/domain/root.zone

   o  From ICANN via HTTP at http://www.internic.net/domain/root.zone

   o  From ICANN by AXFR from DNS servers at xfr.lax.dns.icann.org and
      xfr.cjr.dns.icann.org

   Currently, the root can be retrieved by zone transfer from the
   following root server operators:

   o  b.root-servers.net

   o  c.root-servers.net

   o  f.root-servers.net

   o  g.root-servers.net

   o  k.root-servers.net

Appendix B.  Example Configurations of Common Implementations

   This section shows fragments of configurations for some popular
   recursive server software that is believed to correctly implement the
   requirements given in this document.

B.1.  Example Configuration: BIND 9.9

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   view root {
       match-destinations { 127.12.12.12; };
       zone "." {
           type slave;
           file "rootzone.db";
           notify no;
           masters {
               192.228.79.201; # b.root-servers.net
               192.33.4.12;    # c.root-servers.net
               192.5.5.241;    # f.root-servers.net
               192.112.36.4;   # g.root-servers.net
               193.0.14.129;   # k.root-servers.net
           };
       };
   };

   view recursive {
       dnssec-validation auto;
       allow-recursion { any; };
       recursion yes;
       zone "." {
           type static-stub;
           server-addresses { 127.12.12.12; };
       };
   };

B.2.  Example Configuration: Unbound 1.4 and NSD 4

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   # Configuration for Unbound

   server:
       do-not-query-localhost: no

   stub-zone:
       name: "."
       stub-prime: no
       stub-addr: 127.12.12.12

   # Configuration for NSD
   server:
       ip-address: 127.12.12.12

   zone:
       name: "."
       request-xfr: 192.228.79.201 NOKEY # b.root-servers.net
       request-xfr: 192.33.4.12 NOKEY # c.root-servers.net
       request-xfr: 192.5.5.241 NOKEY # f.root-servers.net
       request-xfr: 192.112.36.4 NOKEY # g.root-servers.net
       request-xfr: 193.0.14.129 NOKEY # k.root-servers.net

Authors' Addresses

   Warren Kumari
   Google

   Email: Warren@kumari.net

   Paul Hoffman
   VPN Consortium

   Email: paul.hoffman@vpnc.org

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