Internet Engineering Task Force (IETF) L. Song, Ed.
Internet-Draft D. Liu, Ed.
Intended status: Informational Beijing Internet Institute
Expires: May 3, 2018 P. Vixie, Ed.
TISF
Kato, Ed.
Keio University/WIDE Project
S. Kerr
October 30, 2017
Yeti DNS Testbed
draft-song-yeti-testbed-experience-05
Abstract
The Internet's Domain Name System (DNS) is built upon the foundation
provided by the Root Server System -- that is, the critical
infrastructure that serves the DNS root zone.
Yeti DNS is an experimental, non-production testbed that aims to
provide an environment where technical and operational experiments
can safely be performed without risk to production infrastructure.
This testbed has been used by a broad community of participants to
perform experiments that aim to inform operations and future
development of the production DNS. Yeti DNS is an independently-
coordinated project and is not affiliated with ICANN, IANA or any
Root Server Operator.
The Yeti DNS testbed implementation includes various novel and
experimental components including IPv6-only transport, independent,
autonomous Zone Signing Key management, large cryptographic keys and
a large number of component Yeti-Root Servers. These differences
from the Root Server System have operational consequences such as
large responses to priming queries and the coordination of a large
pool of independent operators; by deploying such a system globally
but outside the production DNS system, the Yeti DNS project provides
an opportunity to gain insight into those consequences without
threatening the stability of the DNS.
This document neither addresses the relevant policies under which the
Root Server System is operated nor makes any proposal for changing
any aspect of its implementation or operation. This document aims
solely to document technical and operational findings following the
deployment of a system which is similar but different from the Root
Server System.
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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 https://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."
This Internet-Draft will expire on May 3, 2018.
Copyright Notice
Copyright (c) 2017 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
(https://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
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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Areas of Study . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Implementation of a Root Server System-like Testbed . . . 5
2.2. Yeti-Root Zone Distribution . . . . . . . . . . . . . . . 5
2.3. Yeti-Root Server Names and Addressing . . . . . . . . . . 5
2.4. IPv6-Only Yeti-Root Servers . . . . . . . . . . . . . . . 5
2.5. DNSSEC in the Yeti-Root Zone . . . . . . . . . . . . . . 5
3. Yeti DNS Testbed Infrastructure . . . . . . . . . . . . . . . 6
3.1. Root Zone Retrieval . . . . . . . . . . . . . . . . . . . 7
3.2. Transformation of Root Zone to Yeti-Root Zone . . . . . . 8
3.2.1. ZSK and KSK Key Sets Shared Between DMs . . . . . . . 8
3.2.2. Unique ZSK per DM; No Shared KSK . . . . . . . . . . 9
3.2.3. Preserving Root Zone NSEC Chain and ZSK RRSIGs . . . 11
3.3. Yeti-Root Zone Distribution . . . . . . . . . . . . . . . 11
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3.4. Synchronization of Service Metadata . . . . . . . . . . . 11
3.5. Yeti-Root Server Naming Scheme . . . . . . . . . . . . . 12
3.6. Yeti-Root Servers . . . . . . . . . . . . . . . . . . . . 13
3.7. Traffic Capture and Analysis . . . . . . . . . . . . . . 15
4. Operational Experience with Yeti DNS Testbed . . . . . . . . 15
4.1. Automated Hints File Maintenance . . . . . . . . . . . . 15
4.2. IPv6-only root operation . . . . . . . . . . . . . . . . 16
4.2.1. Impact of IPv6 fragmentation . . . . . . . . . . . . 16
4.2.2. How IPv6-only Root serve IPv4 users? . . . . . . . . 18
4.3. Experience on Multiple Signers . . . . . . . . . . . . . 19
4.3.1. IXFR fallback to AXFR . . . . . . . . . . . . . . . . 19
4.3.2. Latency of Root Zone update . . . . . . . . . . . . . 20
4.4. Root Label Compression in Knot . . . . . . . . . . . . . 20
4.5. Increased ZSK Key Size . . . . . . . . . . . . . . . . . 21
4.6. KSK Rollover . . . . . . . . . . . . . . . . . . . . . . 21
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 21
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
Appendix A. Yeti-Root Hints File . . . . . . . . . . . . . . . . 25
Appendix B. Controversy . . . . . . . . . . . . . . . . . . . . 26
Appendix C. About This Document . . . . . . . . . . . . . . . . 27
C.1. Venue . . . . . . . . . . . . . . . . . . . . . . . . . . 27
C.2. Revision History . . . . . . . . . . . . . . . . . . . . 28
C.2.1. draft-song-yeti-testbed-experience-00 through -03 . . 28
C.2.2. draft-song-yeti-testbed-experience-04 . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28
1. Introduction
The Domain Name System (DNS), as originally specified in [RFC1034]
and [RFC1035], has proved to be an enduring and important platform
upon which almost every user of Internet services relies. Despite
its longevity, extensions to the protocol, new implementations and
refinements to DNS operations continue to emerge both inside and
outside the IETF.
The Root Server System in particular has seen technical innovation
and development in recent years, for example in the form of wide-
scale anycast deployment, the mitigation of unwanted traffic on a
global scale, the widespread deployment of Response Rate Limiting
[RRL], the introduction of IPv6 transport, the deployment of DNSSEC,
changes in DNSSEC key sizes and preparations to roll the root zone's
trust anchor. Together, even the projects listed in this brief
summary imply tremendous operational change, all the more impressive
when considered the necessary caution when managing Internet critical
infrastructure, and the context of the adjacent administrative
changes involved in root zone management and the (relatively
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speaking) massive increase in the the number of delegations in the
root zone itself.
Aspects of the operational structure of the Root Server System have
been described in such documents as [TNO2009], [ISC-TN-2003-1],
[RSSAC001] and [RFC7720]. Such references, considered together,
provide sufficient insight into the operations of the system as a
whole that it is straightforward to imagine structural changes to the
root server system's infrastructure, and to wonder what the
operational implications of such changes might be.
The Yeti DNS Project was conceived in May 2015 to provide a captive,
non-production testbed upon which the technical community could
propose and run experiments designed to answer these kinds of
questions. Coordination for the project was provided by TISF, the
WIDE Project and the Beijing Internet Institute. Many volunteers
collaborated to build a distributed testbed that at the time of
writing includes 25 Yeti root servers with 16 operators and handles
experimental traffic from individual volunteers, universities, DNS
vendors and distributed measurement networks.
By design, the Yeti testbed system serves the root zone published by
the IANA with only those structural modifications necessary to ensure
that it is able to function usefully in the Yeti testbed system
instead of the production Root Server system. In particular, no
delegation for any top-level zone is changed, added or removed from
the IANA-published root zone to construct the root zone served by the
Yeti testbed system. In this document, for clarity, we refer to the
zone derived from the IANA-published root zone as the Yeti-Root zone.
The Yeti DNS testbed serves a similar function to the Root Server
System in the sense that they both serve similar zones (the Yeti-Root
zone and the Root zone, respectively). However, the Yeti DNS testbed
only serves clients that are explicitly configured to participate in
the experiment, whereas the Root Server System serves the whole
Internet. The known set of clients has allowed structural changes to
be deployed in the Yeti DNS testbed whose impact on clients can be
measured and analysed.
2. Areas of Study
Examples of topics that the Yeti DNS Testbed was built to address are
included below, each illustrated with indicative questions.
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2.1. Implementation of a Root Server System-like Testbed
o How can a captive testbed be constructed and deployed on the
Internet, allowing useful public participation without any risk of
disruption of the Root Server System?
o How can representative traffic be introduced into such a captive
testbed such that insights into the impact of specific differences
between the testbed and the Root Server System can be observed?
2.2. Yeti-Root Zone Distribution
o What are the scaling properties of Yeti-Root zone distribution as
the number of Yeti-Root servers, Yeti-Root server instances or
intermediate distribution points increase?
2.3. Yeti-Root Server Names and Addressing
o What naming schemes other than those closely analogous to the use
of ROOT-SERVERS.NET in the production root zone are practical, and
what are their respective advantages and disadvantages?
o What are the risks and benefits of signing the zone that contains
the names of the Yeti-Root servers?
o What automatic mechanisms might be useful to improve the rate at
which clients of Yeti-Root servers are able to react to a Yeti-
Root server renumbering event?
2.4. IPv6-Only Yeti-Root Servers
o Are there negative operational effects in the use of IPv6-only
Yeti-Root servers, compared to the use of servers that are dual-
stack?
o What effect does the IPv6 fragmentation model have on the
operation of Yeti-Root servers, compared with that of IPv4?
2.5. DNSSEC in the Yeti-Root Zone
o Is it practical to sign the Yeti-Root zone using multiple,
independently-operated DNSSEC signers and multiple corresponding
ZSKs?
o To what extent is [RFC5011] supported by resolvers?
o Does the KSK Rollover plan designed and in the process of being
implemented by ICANN work as expected on the Yeti testbed?
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o What is the operational impact of using much larger RSA key sizes
in the ZSKs used in the Yeti-Root?
o What are the operational consequences of choosing DNSSEC
algorithms other than RSA to sign the Yeti-Root zone?
3. Yeti DNS Testbed Infrastructure
The purpose of the testbed is to allow DNS queries from stub
resolvers, mediated by recursive resolvers, to be delivered to Yeti-
Root servers, and for corresponding responses generated on the Yeti-
Root servers to be returned, as illustrated in Figure 1.
,----------. ,-----------. ,------------.
| stub +------> | recursive +------> | Yeti-Root |
| resolver | <------+ resolver | <------+ nameserver |
`----------' `-----------' `------------'
^ ^ ^
| appropriate | Yeti-Root hints; | Yeti-Root zone
`- resolver `- Yeti-Root trust `- with DNSKEY RRSet,
configured anchor signed by Yeti-KSK
Figure 1: High-Level Testbed Components
To use the Yeti DNS testbed, a stub resolver must be explicitly
configured to use recursive resolvers that have themselves been
configured to use the Yeti-Root servers. On the resolvers, that
configuration consists of a list of names and addresses for the Yeti-
Root servers (often referred to as a "hints file") that replaces the
normal Internet DNS hints. Resolvers also need to be configured with
a DNSSEC trust anchor that corresponds to a KSK used in the Yeti DNS
Project, in place of the normal trust anchor for the root zone.
The need for a Yeti-specific trust anchor in the resolver stems from
the need to make minimal changes to the root zone, as retrieved from
the IANA, to transform it into the Yeti-Root that can be used in the
testbed. Those changes would be properly rejected by any validator
using an accurate root zone trust anchor as bogus. Corresponding
changes are required in the Yeti-Root hints file Appendix A.
The data flow from IANA to stub resolvers through the Yeti testbed is
illustrated in Figure 2 and are described in more detail in the
sections that follow.
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,----------------.
,-- / IANA Root Zone / ---.
| `----------------' |
| | |
| | | Root Zone
,--------------. ,---V---. ,---V---. ,---V---.
| Yeti Traffic | | BII | | WIDE | | TISF |
| Collection | | DM | | DM | | DM |
`----+----+----' `---+---' `---+---' `---+---'
| | ,-----' ,-------' `----.
| | | | | Yeti-Root
^ ^ | | | Zone
| | ,---V---. ,---V---. ,---V---.
| `---+ Yeti | | Yeti | . . . . . . . | Yeti |
| | Root | | Root | | Root |
| `---+---' `---+---' `---+---'
| | | | DNS
| | | | Response
| ,--V----------V-------------------------V--.
`---------+ Yeti Resolvers |
`--------------------+---------------------'
| DNS
| Response
,--------------------V---------------------.
| Yeti Stub Resolvers |
`------------------------------------------'
Figure 2: Testbed Data Flow
3.1. Root Zone Retrieval
Since Yeti DNS servers cannot receive DNS NOTIFY [RFC1996] messages
from the Root Server System, a polling approach is used. Each Yeti
Distribution Master (DM) requests the root zone SOA record from a
nameserver that permits unauthenticated zone transfers of the root
zone, and performs a zone transfer from that server if the retrieved
value of SOA.SERIAL is greater than that of the last retrieved zone.
At the time of writing, unauthenticated zone transfers of the root
zone are available directly from B-Root, C-Root, F-Root, G-Root and
K-Root, and from L-Root via the two servers XFR.CJR.DNS.ICANN.ORG and
XFR.LAX.DNS.ICANN.ORG, as well as via FTP from sites maintained by
the Root Zone Maintainer and the IANA Functions Operator. The Yeti
DNS Testbed retrieves the root zone from using zone transfers from
F-Root. The schedule on which F-Root is polled by each Yeti DM is as
follows:
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+-------------+-----------------------+
| DM Operator | Time |
+-------------+-----------------------+
| BII | UTC hour + 00 minutes |
| WIDE | UTC hour + 20 minutes |
| TISF | UTC hour + 40 minutes |
+-------------+-----------------------+
The Yeti DNS testbed uses multiple DMs, each of which acts
autonomously and equivalently to its siblings. Any single DM can act
to distribute new revisions of the Yeti-Root zone, and is also
responsible for signing the RRSets that are changed as part of the
transformation of the Root Zone into the Yeti-Root zone described in
Section 3.2. This shared control over the processing and
distribution of the Yeti-Root zone approximates some of the ideas
around shared zone control explored in [ITI2014].
3.2. Transformation of Root Zone to Yeti-Root Zone
Two distinct approaches have been deployed in the Yeti-DNS Testbed,
separately, to transform the Root Zone into the Yeti-Root Zone. At a
high level both approaches are equivalent in the sense that they
replace a minimal set of information in the Root Zone with
corresponding data corresponding to the Yeti DNS Testbed; the
mechanisms by which the transforms are executed are different,
however. Each is discussed in turn in Section 3.2.1 and
Section 3.2.2, respectively.
A third approach has also been proposed, but not yet implemented.
The motivations and changes implied by that approach are also
described in Section 3.2.3.
3.2.1. ZSK and KSK Key Sets Shared Between DMs
The approach described here was the first to be implemented. It
features entirely autonomous operation of each DM, but also requires
secret key material (the private parts of all Yeti-Root KSK and ZSK
key-pairs) to be distributed and maintained on each DM in a
coordinated way.
The Root Zone is transformed as follows to produce the Yeti-Root
Zone. This transformation is carried out autonomously on each Yeti
DNS Project DM. Each DM carries an authentic copy of the current set
of Yeti KSK and ZSK key pairs, synchronised between all DMs (see
Section 3.4).
1. SOA.MNAME is set to www.yeti-dns.org.
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2. SOA.RNAME is set to <dm-operator>.yeti-dns.org. where <dm-
operator> is currently one of "wide", "bii" or "tisf".
3. All DNSKEY, RRSIG and NSEC records are removed.
4. The apex NS RRSet is removed, with the corresponding root server
glue RRSets.
5. A Yeti DNSKEY RRSet is added to the apex, comprising the public
parts of all Yeti KSK and ZSKs.
6. A Yeti NS RRSet is added to the apex that includes all Yeti-Root
servers.
7. Glue records (AAAA, since Yeti-Root servers are v6-only) for all
Yeti-Root servers are added.
8. The Yeti-Root Zone is signed: the NSEC chain is regenerated; the
Yeti KSK is used to sign the DNSKEY RRSet, and the DM's local ZSK
to generate every other RRSet.
Note that the SOA.SERIAL value published in the Yeti-Root Zone is
identical to that found in the Root Zone.
3.2.2. Unique ZSK per DM; No Shared KSK
The approach described here was the second to be implemented. Each
DM is provisioned with its own, dedicated ZSK key pairs that are not
shared with other DMs. A Yeti-Root DNSKEY RRSet is constructed and
signed upstream of all DMs as the union of the set of active KSKs and
the set of active ZSKs for every individual DM. Each DM now only
requires the secret part of its own dedicated ZSK key pairs to be
available locally, and no other secret key material is shared. The
high-level approach is illustrated in Figure 3.
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,----------. ,-----------.
.--------> BII ZSK +---------> Yeti-Root |
| signs `----------' signs `-----------'
|
,-----------. | ,----------. ,-----------.
| Yeti KSK +-+--------> TISF ZSK +---------> Yeti-Root |
`-----------' | signs `----------' signs `-----------'
|
| ,----------. ,-----------.
`--------> WIDE ZSK +---------> Yeti-Root |
signs `----------' signs `-----------'
Figure 3: Unique ZSK per DM
The process of retrieving the Root Zone from the Root Server System
and replacing and signing the apex DNSKEY RRSet no longer takes place
on the DMs, and instead takes place on a central Hidden Master. The
production of signed DNSKEY RRSets is analogous to the use of Signed
Key Responses (SKR) produced during ICANN KSK key ceremonies.
Each DM now retrieves source data (with pre-modified and Yeti-signed
DNSKEY RRset, but otherwise unchanged) from the Yeti DNS Hidden
Master instead of from the Root Server System.
Each DM carries out a similar transformation to that described in
Section 3.2.1, except that DMs no longer need to modify or sign the
DNSKEY RRSet.
The Yeti-Root Zone served by any particular Yeti-Root Server will
include signatures generated using the ZSK from the DM that served
the Yeti-Root Zone to that Yeti-Root Server. Signatures cached at
resolvers might be retrieved from any Yeti-Root Server, and hence are
expected to be a mixture of signatures generated by different ZSKs.
Since all ZSKs can be trusted through the signature by the Yeti KSK
over the DNSKEY RRSet, which includes all ZSKs, the mixture of
signatures was predicted not to be a threat to reliable validation.
Deployment and experimentation confirms this to be the case, even
when individual ZSKs are rolled on different schedules.
A consequence of this approach is that the apex DNSKEY RRSet in the
Yeti-Root zone is much larger than the corresponding DNSKEY RRSet in
the Root Zone.
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3.2.3. Preserving Root Zone NSEC Chain and ZSK RRSIGs
A change to the transformation described in Section 3.2.2 has been
proposed that would preserve the NSEC chain from the Root Zone and
all RRSIG RRs generated using the Root Zone's ZSKs. The DNSKEY RRSet
would continue to be modified to replace the Root Zone KSKs, and the
Yeti KSK would be used to generate replacement signatures over the
apex DNSKEY and NS RRSets. Source data would continue to flow from
the Root Server System through the Hidden Master to the set of DMs,
but no DNSSEC operations would be required on the DMs and the source
NSEC and most RRSIGs would remain intact.
This approach has been suggested in order to provide
cryptographically-verifiable confidence that no owner name in the
root zone had been changed in the process of producing the Yeti-Root
zone from the Root Zone, addressing one of the concerns described in
Appendix B in a way that can be verified automatically.
3.3. Yeti-Root Zone Distribution
Each Yeti DM is configured with a full list of Yeti-Root Server
addresses to send NOTIFY messages to, and to form the basis for an
address-based access-control list for zone transfers. Authentication
by address could be replaced with more rigourous mechanisms (e.g.
using Transaction Signatures (TSIG) [RFC2845]); this has not been
done at the time of writing since the use of address-based controls
avoid the need for the distribution of shared secrets amongst the
Yeti-Root Server Operators.
Individual Yeti-Root Servers are configured with a full set of Yeti
DM addresses to which SOA and AXFR requests may be sent in the
conventional manner.
3.4. Synchronization of Service Metadata
Changes in the Yeti-DNS Testbed infrastructure such as the addition
or removal of Yeti-Root servers, renumbering Yeti-Root Servers or
DNSSEC key rollovers require coordinated changes to take place on all
DMs. The Yeti-DNS Testbed is subject to more frequent changes than
are observed in the Root Server System and includes substantially
more Yeti-Root Servers than there are Root Servers, and hence a
manual change process in the Yeti Testbed would be more likely to
suffer from human error. An automated process was consequently
implemented.
A repository of all service metadata involved in the operation of
each DM was implemented as a separate git repository hosted at
github.com, since this provided a simple, transparent and familiar
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mechanism for participants to review. Requests to change the service
metadata for a DM are submitted as pull requests from a fork of the
corresponding repository; each DM operator reviews pull requests and
merges them to indicate approval. Once merged, changes are pulled
automatically to individual DMs and promoted to production.
3.5. Yeti-Root Server Naming Scheme
The current naming scheme for Root Servers was normalized to use
single-character host names (A through M) under the domain ROOT-
SERVERS.NET, as described in [RSSAC023]). The principal benefit of
this naming scheme is that DNS label compression can be used to
produce a priming response that will fit within 512 bytes, the
maximum DNS message size using UDP transport without EDNS0 [RFC6891].
Yeti-Root Servers do not use this optimisation, but rather use free-
form nameserver names chosen by their respective operators -- in
other words, no attempt is made to minimise the size of the priming
response through the use of label compression. This approach aims to
challenge the need for a minimally-sized priming response in a modern
DNS ecosystem where EDNS(0) is prevalent.
Priming responses from Yeti-Root Servers do not always include server
addresses in the additional section, as is the case with priming
responses from Root Servers. In particular, Yeti-Root Servers
running BIND9 return an empty additional section, forcing resolvers
to complete the priming process with a set of conventional recursive
lookups in order to resolve addresses for each Yeti-Root server.
Yeti-Root Servers running NSD appeared to return a fully-populated
additional section.
Various approaches to normalise the composition of the priming
response were considered, including:
o Require use of DNS implementations that exhibit the desired
behaviour in the priming response (e.g. NSD) in favour of BIND9;
o Modification of BIND9 (and any other server with similar
behaviour) for use by Yeti-Root Servers;
o Isolate the names of Yeti-Root Servers in one or more zones that
could be slaved on each Yeti-Root Server, renaming servers as
necessary, giving each a source of authoritative data with which
the authority section of a priming response could be fully
populated. This is the approach used in the Root Server System.
The potential mitigation of renaming all Yeti-Root Servers using a
scheme that would allow their names to exist in the balliwick of the
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root zone was not considered, since that approach implies the
invention of new top-level labels not present in the Root Zone.
Given the relative infrequency of priming queries by individual
resolvers and the additional complexity or other compromises implied
by each of those mitigations, the decision was made to make no effort
to ensure that the composition of priming responses was identical
across servers. Even the empty additional sections generated by
Yeti-Root Servers running BIND9 seem to be sufficient for all
resolver software tested; resolvers simply perform a new recursive
lookup for each authoritative server name they need to resolve.
3.6. Yeti-Root Servers
Various volunteers have donated authoritative servers to act as Yeti-
Root servers. At the time of writing there are 25 Yeti-Root servers
distributed globally, one of which is named using an IDNA2008
[RFC5890] label, shown in the following list in punycode.
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+-------------------------------------+---------------+-------------+
| Name | Operator | Location |
+-------------------------------------+---------------+-------------+
| bii.dns-lab.net | BII | CHINA |
| yet-ns.tsif.net | TSIF | USA |
| yeti-ns.wide.ad.jp | WIDE Project | Japan |
| yeti-ns.as59715.net | as59715 | Italy |
| dahu1.yeti.eu.org | Dahu Group | France |
| ns-yeti.bondis.org | Bond Internet | Spain |
| | Systems | |
| yeti-ns.ix.ru | Russia | MSK-IX |
| yeti.bofh.priv.at | CERT Austria | Austria |
| yeti.ipv6.ernet.in | ERNET India | India |
| yeti-dns01.dnsworkshop.org | dnsworkshop | Germany |
| | /informnis | |
| yeti-ns.conit.co | CONIT S.A.S | Colombia |
| dahu2.yeti.eu.org | Dahu Group | France |
| yeti.aquaray.com | Aqua Ray SAS | France |
| yeti-ns.switch.ch | SWITCH | Switzerland |
| yeti-ns.lab.nic.cl | CHILE NIC | Chile |
| yeti-ns1.dns-lab.net | BII | China |
| yeti-ns2.dns-lab.net | BII | China |
| yeti-ns3.dns-lab.net | BII | China |
| ca...a23dc.yeti-dns.net | Yeti-ZA | South |
| | | Africa |
| 3f...374cd.yeti-dns.net | Yeti-AU | Australia |
| yeti1.ipv6.ernet.in | ERNET India | India |
| xn--r2bi1c.xn--h2bv6c0a.xn--h2brj9c | ERNET India | India |
| yeti-dns02.dnsworkshop.org | dnsworkshop | USA |
| | /informnis | |
| yeti.mind-dns.nl | Monshouwer | Netherlands |
| | Internet | |
| | Diensten | |
| yeti-ns.datev.net | DATEV | Germany |
+-------------------------------------+---------------+-------------+
The current list of Yeti-Root server is made available to a
participating resolver first using a substitute hints file Appendix A
and subsequently by the usual resolver priming process
[I-D.ietf-dnsop-resolver-priming]. All Yeti-Root servers are
IPv6-only, foreshadowing a future IPv6-only Internet, and hence the
Yeti-Root hints file contains no IPv4 addresses and the Yeti-Root
zone contains no IPv4 glue.
At the time of writing, all root servers within the Root Server
System serve the ROOT-SERVERS.NET zone in addition to the root zone,
and all but one also serve the ARPA zone. Yeti-Root servers serve
the Yeti-Root zone only.
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Significant software diversity exists across the set of Yeti-Root
servers, as reported by their volunteer operators:
o Platform: 20 of 25 Yeti-Root servers are implemented on a VPS
rather than bare metal.
o Operating System: 6 Yeti-Root servers run on on Linux (Ubuntu,
Debian, CentOS, and ArchLinux); 5 run on FreeBSD and 1 on NetBSD.
o DNS software: 18 of 25 Yeti-Root servers use BIND9 (versions
varying between 9.9.7 and 9.10.3); four use NSD (4.10 and 4.15);
two use Knot (2.0.1 and 2.1.0) and one uses Bundy (1.2.0).
3.7. Traffic Capture and Analysis
Query and response traffic capture is available in the testbed in
both Yeti resolvers and Yeti-Root servers in anticipation of
experiments that require packet-level visibility into DNS traffic.
Traffic capture is performed on Yeti-Root servers using either dnscap
<https://www.dns-oarc.net/tools/dnscap> or pcapdump (part of the
pcaputils Debian package <https://packages.debian.org/sid/pcaputils>,
with a patch to facilitate triggered file upload
<https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=545985>. PCAP-
format files containing packet captures are uploaded using rsync to
central storage.
4. Operational Experience with Yeti DNS Testbed
The following sections provide commentary on the operation and impact
analyses of the Yeti-DNS Testbed described in Section 3. More
detailed descriptions of observed phenomena are available in Yeti DNS
mailing list archives and on the Yeti DNS blog.
4.1. Automated Hints File Maintenance
Renumbering events in the Root Server System are relatively rare.
Although each such event is accompanied by the publication of an
updated hints file in standard locations, the task of updating local
copies of that file used by DNS resolvers is manual, and the process
has an observably-long tail: for example, in 2015 J-Root was still
receiving traffic at its old address some thirteen years after
renumbering [Wessels2015].
The observed impact of these old, deployed hints file is minimal,
likely due to the very low frequency of such renumbering events.
Even the oldest of hints file would still contain some accurate root
server addresses from which priming responses could be obtained.
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By contrast, due to the experimental nature of the system and the
fact that it is operated mainly by volunteers, Yeti-Root Servers are
added, removed and renumbered with much greater frequency. A tool to
facilitate automatic maintenance of hints files was therefore
created, [hintUpdate].
The automated procedure followed by the hintUpdate tool is as
follows.
1. Use the local resolver to obtain a response to the query ./IN/NS;
2. Use the local resolver to obtain a set of IPv4 and IPv6 addresses
for each nameserver;
3. Validate all signatures obtained from the local resolvers, and
confirm that all data is signed;
4. Compare the data obtained to that contained within the currently-
active hints file; if there are differences, rotate the old one
way and replace it with a new one.
This tool would not function unmodified when used in the Root Server
System, since the names of individual Root Servers (e.g. A.ROOT-
SERVERS.NET) are not signed. All Yeti-Root Server names are signed,
however, and hence this tool functions as expected in that
environment.
4.2. IPv6-only root operation
Yeti DNS testbed was designed to explore whether it can survive in
pure IPv6 environment or not. So every root server required to run
only with non-EUI64 IPv6 addressed. There are mainly two questions
in designers' mind when constructing this testbed: 1) is there any
gap between IPv6-only Root and IPv4 Root to provide full function of
root server. 2) is it possible that IPv6-only root can serve the
Internet, even part of which still only speak IPv4. There are some
findings and impacts which IPv6-only property bring to Root system.
4.2.1. Impact of IPv6 fragmentation
In the Root Server System, structural changes with the potential to
increase response sizes (and hence fragmentation, fallback to TCP
transport or both) have been exercised with great care, since the
impact on clients has been difficult to predict or measure. The Yeti
DNS Testbed is experimental and has the luxury of a known client
base, making it far easier to make such changes and measure their
impact.
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Many of the experimental design choices described in this document
were expected to trigger larger responses. For example, the choice
of naming scheme for Yeti-Root Servers described in Section 3.5
defeats label compression the priming response which introduce a
large priming response (up to 1754 octets with 25 NS server and their
glue) ; the Yeti-Root zone transformation approach described in
Section 3.2.2 greatly enlarges the apex DNSKEY RRSet especially
during the KSK rollover (up to 1975 octets with 3 ZSK and 2 KSK). An
increased incidence of fragmentation was therefore expected.
The Yeti-DNS Testbed provides service on IPv6 only. IPv6 has a
fragmentation model that is different from IPv4 -- in particular,
fragmentation always takes place on a sending end-host, and not on an
intermediate router.
Fragmentation may cause serious issues; if a single fragment is lost,
it results in the loss of the entire datagram of which the fragment
was a part, and in the DNS frequently triggers a timeout. It is
known at this moment that only a limited number of security middle-
box implementations support IPv6 fragments. Some public measurements
and reports [I-D.taylor-v6ops-fragdrop] [RFC7872] shows that there is
notable packets drop rate due to the mistreatment of middle-box on
IPv6 fragment. One APNIC study [IPv6-frag-DNS] reported that 37% of
endpoints using IPv6-capable DNS resolver cannot receive a fragmented
IPv6 response over UDP.
To study the impact, RIPE Atlas probes are used to spot failures like
timeout for DNSKEY queries via UDP. For each Yeti server, a Atlas
measurement was setup asking for 100 IPv6-enabled probes from 5
regions, in each 2 hours sending DNS query for DNSKEY via UDP with DO
bit set. An monitoring report during Yeti KSK rollover shows that
statistically large packets will trigger higher failure rate (up to
7%) due to IPv6 fragmentation issues, which accordingly increase
probability of retries and TCP fallback. Even within 1500 bytes,
when response size reaches 1414 bytes, the failure rate reaches
around 2%. Note that ICANN KSK rollover will produce packets
exceeding 1414 Bytes.
Regarding the large DNS response via UDP, some existing root
servers(A, B, G and J) truncating the response once the large IPv6
packet surpasses 1280 octets. In Yeti DNS Testbed, there are two
proposals are discussed and implemented in Yeti experiments.One
proposal is called DNS fragments [I-D.muks-dns-message-fragments]
which is to fragment the large response in DNS level. Another
proposal is called DNS ATR [I-D.song-atr-large-resp] which introduces
an simple improvement on authoritative server by replying additional
truncated response just after the normal large response.
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The consequences of fragmentation were not limited to DNS using UDP
transport. There are two cases reported where some Yeti root servers
failed to transfer the Yeti-Root zone from a DM. When checking the
DM log file, it is found that some root servers experienced " socket
is not connected" errors when they pulled the zone file. Further
experimentation revealed that combinations of NetBSD 6.1, NetBSD
7.0RC1, FreeBSD 10.0, Debian 3.2 and VMWare ESXI 5.5 resulted in a
high TCP MSS value of 1440 octets being negotiated between client and
server despite the presence of the IPV6_USE_MIN_MTU socket option, as
described in [I-D.andrews-tcp-and-ipv6-use-minmtu]. The mismatch
appears to cause outbound segments greater in size than 1280 octets
to be dropped before sending.
One proposal to handle this issue is to change the Local TCP MSS to
be 1220 (1280-ip6/tcp header)and advise it if IPV6_USE_MINMTU=1.
Yeti root from WIDE and SWITCH set this during the test one year ago.
Now at the time of writing, 11 out of 25 change the MSS setting in
Yeti DNS Testbed.
4.2.2. How IPv6-only Root serve IPv4 users?
Although It is straightforward to setup the IPv6-only root, but it is
unknown if it is practical for IPv6-only root to serve the production
networks which are still largely speak only in IPv4. In Yeti DNS
Testbed it is demonstrated that IPv6-only root can serve the Internet
in a incremental approach, even for IPv4 network and users.
It is intuitive to propose to update the resolver to dual-stack and
configured it with hint file including IPv6 glues. The dual-stack
resolver connects IPv6 root with IPv4-only or dual-stack end users.
However, when we approached some partners who agreed to try IPv6-only
root in experimental network, they normally do not want to give up
the IPv4 root for redundancy reason due to unstable IPv6 network
performance. So it is adopted in campuses that one IPv4 resolver
address (using current IPv4 addresses of A-M root) and one IPv6
resolver address (using Yeti root) are configured for their customer
via DHCPv4 and DHCPv6 respectively. The end users can choose which
DNS they use (normally IPv6 first or using Happy eyeballs). Ideally,
the end users DNS traffic will largely be sent to the resolver
consuming IPv6-only root when IPv6 is widely deployed.
For resolvers who resident in IPv4 only networks, they can forward
the query to dual stack resolvers they have trust in. Or they can
configure the resolver with a hint file containing a set of IPv4
addresses which are mapped to IPv6 addresses of root in a IPv4/IPv6
translation devices. The query will be routed to the translation
devices and forward in IPv6 to IPv6-only root. It is designed and
going to be implemented in CERNET2 using IVI [RFC6219] technology.
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4.3. Experience on Multiple Signers
In Section 3 it is introduced how three Distributor Masters (DM)
works and how they share the control over the Yeti root zone. This
section will describe some findings and experiences on its operation.
4.3.1. IXFR fallback to AXFR
In DNS specifications authoritative name server uses full zone
transfer (AXFR) [RFC5936], incremental Zone Transfer (IXFR)[RFC1995],
and NOTIFY [RFC1996] to achieve coherency of the zone contents. IXFR
is an optimization for large DNS zone transfer, which allows server
only transfer the changed portion(s) to client. AXFR fallback
usually happens at server side by simply returning IXFR client the
entire new zone in condition that IXFR server cannot fulfill the
given delta-update request.
One experiment in Yeti is designed to test multiple signers with
Multiple ZSKs (MZSK). It is required that all public ZSKs used by
DMs are included in the zone as a key set; and resolver can validate
the message by picking one key from the key set. From DNSSEC point
of view, it is technically workable. However, different signers do
produce different RRSIG RR which introduces zone inconsistency from
beginning in this case. In current setting of Yeti experiment, it is
possible that one client does AXFR/IXFR from one server and later
asks for IXFR from another server.
It is observed that when the IXFR client switched from one IXFR
server to another, it received a IXFR response deleting RRSIG record
that does not exist. One IXFR client running NSD 4.1.7 rejected IXFR
response, made a log indicating a bad data and then asked for full
zone transfer. Luckily, Yeti root zone is relatively small (691K),
so the fallback to AXFR does not cause significant performance
degeneration. But if operator does host big zone with MZSK model, it
will cause problem based on current IXFR.
Another observation is that another IXFR client running Knot 2.1.0 in
similar situation just accepts the IXFR response, ignores the
differences and generates a merged zone with two RRSIG RRs. It not
only produces larger response, but also causes DNSSEC failure when a
new zone is generated given that old RRSIG is the signature of old
zone RRs.
One possible solutions is asking for development of RRSIG-aware IXFR
format in which the RRSIG is treated as a special and RRSIG RR should
always be transfered in full (like it does in AXFR). Another
solution is adopting the behavior of NSD 4.1.7 as a improvement for
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IXFR protocol in which an IXFR client should fall back to AXFR
automatically in the event of an IXFR incoherence error.
4.3.2. Latency of Root Zone update
Regarding the timing of Root Zone fetch and soa update, Each Yeti DM
checks the root zone serial hourly (in 20 minutes interval) to see if
the IANA root zone has changed . A new version of the Yeti root zone
is generated if the IANA root zone has changed. In this model, root
servers is expected pull the zone from one DM for each new update,
because 20 min is expected to be enough for root zone publication.
But it is not the true in Yeti testbed in a monitoring test.
It once was reported that one server running on Bundy 1.2.0 on
FreeBSD 10.2-RELEASE had some bugs on SOA update with more than 10
hours delay. Besides that server, half of Yeti servers has more than
20 min delay, some even with 40 min delay. One possible reason may
be that the server failed to pull the Zone on one DM due to network
failure(for example IPv6 fragmentation issue introduce previously)
and turn to another DM which introduces the delay. It is also
observed that even in the same 20-minutes time frame, not all servers
pull from a single DM. It is possible that some servers not use FCFS
strategy to pull the zone after they receive the notify. They may
pull the zone based on other metrics like the rtt , or manual
preference.
4.4. Root Label Compression in Knot
[RFC1035] specifies that domain names can be compressed when encoded
in DNS messages, being represented as one of
1. a sequence of labels ending in a zero octet;
2. a pointer; or
3. a sequence of labels ending with a pointer.
The purpose of this flexibility is to reduce the size of domain names
encoded in DNS messages.
It was observed that Yeti-Root Servers running knot 2.0 would
compress the zero-length label (the root domain, often represented as
".") using a pointer to an earlier example. Although legal, this
encoding increases the encoded size of the root label from one octet
to two; it was also found to break some client software, in
particular the Go DNS library. Bug reports were filed against both
knot and the Go DNS library, and both were resolved in subsequent
releases.
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4.5. Increased ZSK Key Size
The ZSK key size used in the Yeti-DNS Testbed was initially 1024
bits, consistent with the size of the ZSK used in the Root Zone at
the time the Yeti DNS Project was started. It later became clear
that the ZSK key size in the Root Zone was to be increased.
The ZSK key size in the Yeti-Root zone was subsequently increased in
an attempt to identify any unexpected operational effects of doing
so.
XXX Note to reviewers: observations following that change to be
inserted here. XXX
The ZSK key size in the Root Zone was increased from 1024 bits to
2048 bits in October 2016. [Verisign2016].
4.6. KSK Rollover
The Root Zone KSK is expected to undergo a carefully-orchestrated
rollover as described in [ICANN2016]. ICANN has commissioned various
tests and has published an external test plan [ICANN2017].
The planned approach was also modelled in the Yeti-DNS Testbed.
XXX Note to reviewers: observations about the KSK rollover in the
Yeti-Root zone to be inserted here. XXX
5. IANA Considerations
This document requests no action of the IANA.
6. Acknowledgments
The editors would like to acknowledge the contributions of the
various and many subscribers to the Yeti DNS Project mailing lists,
including the following people who were involved in the
implementation and operation of the Yeti DNS testbed itself:
Tomohiro Ishihara, Antonio Prado, Stephane Bortzmeyer, Mickael
Jouanne, Pierre Beyssac, Joao Damas, Pavel Khramtsov, Ma Yan,
Otmar Lendl, Praveen Misra, Carsten Strotmann, Edwin Gomez, Remi
Gacogne, Guillaume de Lafond, Yves Bovard, Hugo Salgado-Hernandez,
Li Zhen, Daobiao Gong, Runxia Wan.
The editors also acknowledge the contributions of the Independent
Submissions Editorial Board, and of the following reviewers whose
opinions helped improve the clarity of this document:
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Subramanian Moonesamy, Joe Abley.
7. References
[hintUpdate]
"Hintfile Auto Update", 2015,
<https://github.com/BII-Lab/Hintfile-Auto-Update>.
[I-D.andrews-tcp-and-ipv6-use-minmtu]
Andrews, M., "TCP Fails To Respect IPV6_USE_MIN_MTU",
draft-andrews-tcp-and-ipv6-use-minmtu-04 (work in
progress), October 2015.
[I-D.ietf-dnsop-resolver-priming]
Koch, P., Larson, M., and P. Hoffman, "Initializing a DNS
Resolver with Priming Queries", draft-ietf-dnsop-resolver-
priming-07 (work in progress), March 2016.
[I-D.muks-dns-message-fragments]
Sivaraman, M., Kerr, S., and D. Song, "DNS message
fragments", draft-muks-dns-message-fragments-00 (work in
progress), July 2015.
[I-D.song-atr-large-resp]
Song, L., "ATR: Additional Truncated Response for Large
DNS Response", draft-song-atr-large-resp-00 (work in
progress), September 2017.
[I-D.taylor-v6ops-fragdrop]
Jaeggli, J., Colitti, L., Kumari, W., Vyncke, E., Kaeo,
M., and T. Taylor, "Why Operators Filter Fragments and
What It Implies", draft-taylor-v6ops-fragdrop-02 (work in
progress), December 2013.
[ICANN2016]
"Root Zone KSK Rollover Plan", 2016,
<https://www.iana.org/reports/2016/
root-ksk-rollover-design-20160307.pdf>.
[ICANN2017]
"2017 KSK Rollover External Test Plan", July 2016,
<https://www.icann.org/en/system/files/files/
ksk-rollover-external-test-plan-22jul16-en.pdf>.
[IPv6-frag-DNS]
"Dealing with IPv6 fragmentation in the DNS", August 2017,
<https://blog.apnic.net/2017/08/22/
dealing-ipv6-fragmentation-dns>.
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[ISC-TN-2003-1]
Abley, J., "Hierarchical Anycast for Global Service
Distribution", March 2003,
<http://ftp.isc.org/isc/pubs/tn/isc-tn-2003-1.txt>.
[ITI2014] "Identifier Technology Innovation Report", May 2014,
<https://www.icann.org/en/system/files/files/
iti-report-15may14-en.pdf>.
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
<https://www.rfc-editor.org/info/rfc1034>.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
November 1987, <https://www.rfc-editor.org/info/rfc1035>.
[RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995,
DOI 10.17487/RFC1995, August 1996,
<https://www.rfc-editor.org/info/rfc1995>.
[RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone
Changes (DNS NOTIFY)", RFC 1996, DOI 10.17487/RFC1996,
August 1996, <https://www.rfc-editor.org/info/rfc1996>.
[RFC2826] Internet Architecture Board, "IAB Technical Comment on the
Unique DNS Root", RFC 2826, DOI 10.17487/RFC2826, May
2000, <https://www.rfc-editor.org/info/rfc2826>.
[RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.
Wellington, "Secret Key Transaction Authentication for DNS
(TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000,
<https://www.rfc-editor.org/info/rfc2845>.
[RFC5011] StJohns, M., "Automated Updates of DNS Security (DNSSEC)
Trust Anchors", STD 74, RFC 5011, DOI 10.17487/RFC5011,
September 2007, <https://www.rfc-editor.org/info/rfc5011>.
[RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
RFC 5890, DOI 10.17487/RFC5890, August 2010,
<https://www.rfc-editor.org/info/rfc5890>.
[RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol
(AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010,
<https://www.rfc-editor.org/info/rfc5936>.
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[RFC6219] Li, X., Bao, C., Chen, M., Zhang, H., and J. Wu, "The
China Education and Research Network (CERNET) IVI
Translation Design and Deployment for the IPv4/IPv6
Coexistence and Transition", RFC 6219,
DOI 10.17487/RFC6219, May 2011,
<https://www.rfc-editor.org/info/rfc6219>.
[RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms
for DNS (EDNS(0))", STD 75, RFC 6891,
DOI 10.17487/RFC6891, April 2013,
<https://www.rfc-editor.org/info/rfc6891>.
[RFC7720] Blanchet, M. and L-J. Liman, "DNS Root Name Service
Protocol and Deployment Requirements", BCP 40, RFC 7720,
DOI 10.17487/RFC7720, December 2015,
<https://www.rfc-editor.org/info/rfc7720>.
[RFC7872] Gont, F., Linkova, J., Chown, T., and W. Liu,
"Observations on the Dropping of Packets with IPv6
Extension Headers in the Real World", RFC 7872,
DOI 10.17487/RFC7872, June 2016,
<https://www.rfc-editor.org/info/rfc7872>.
[RRL] Vixie, P. and V. Schryver, "Response Rate Limiting (RRL)",
June 2012, <http://www.redbarn.org/dns/ratelimits>.
[]
"Service Expectations of Root Servers", December 2015,
<https://www.icann.org/en/system/files/files/
rssac-001-root-service-expectations-04dec15-en.pdf>.
[]
"History of the Root Server System", November 2016,
<https://www.icann.org/en/system/files/files/
rssac-023-04nov16-en.pdf>.
[TNO2009] Gijsen, B., Jamakovic, A., and F. Roijers, "Root Scaling
Study: Description of the DNS Root Scaling Model",
September 2009,
<https://www.icann.org/en/system/files/files/
root-scaling-model-description-29sep09-en.pdf>.
[Verisign2016]
Wessels, D., "Increasing the Strength of the Zone Signing
Key for the Root Zone", May 2016,
<https://blog.verisign.com/security/increasing-the-
strength-of-the-zone-signing-key-for-the-root-zone/>.
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[Wessels2015]
Wessels, D., "Thirteen Years of "Old J-Root"", 2015,
<https://indico.dns-
oarc.net/event/24/session/10/contribution/10/material/
slides/0.pdf>.
Appendix A. Yeti-Root Hints File
The following hints file (complete and accurate at the time of
writing) causes a DNS resolver to use the Yeti DNS testbed in place
of the production Root Server System and hence participate in
experiments running on the testbed.
Note that some lines have been wrapped in the text that follows in
order to fit within the production constraints of this document.
Wrapped lines are indicated with a blackslash character ("\"),
following common convention.
. 3600000 IN NS bii.dns-lab.net
bii.dns-lab.net 3600000 IN AAAA 240c:f:1:22::6
. 3600000 IN NS yeti-ns.tisf.net
yeti-ns.tisf.net 3600000 IN AAAA 2001:559:8000::6
. 3600000 IN NS yeti-ns.wide.ad.jp
yeti-ns.wide.ad.jp 3600000 IN AAAA 2001:200:1d9::35
. 3600000 IN NS yeti-ns.as59715.net
yeti-ns.as59715.net 3600000 IN AAAA \
2a02:cdc5:9715:0:185:5:203:53
. 3600000 IN NS dahu1.yeti.eu.org
dahu1.yeti.eu.org 3600000 IN AAAA \
2001:4b98:dc2:45:216:3eff:fe4b:8c5b
. 3600000 IN NS ns-yeti.bondis.org
ns-yeti.bondis.org 3600000 IN AAAA 2a02:2810:0:405::250
. 3600000 IN NS yeti-ns.ix.ru
yeti-ns.ix.ru 3600000 IN AAAA 2001:6d0:6d06::53
. 3600000 IN NS yeti.bofh.priv.at
yeti.bofh.priv.at 3600000 IN AAAA 2a01:4f8:161:6106:1::10
. 3600000 IN NS yeti.ipv6.ernet.in
yeti.ipv6.ernet.in 3600000 IN AAAA 2001:e30:1c1e:1::333
. 3600000 IN NS yeti-dns01.dnsworkshop.org
yeti-dns01.dnsworkshop.org \
3600000 IN AAAA 2001:1608:10:167:32e::53
. 3600000 IN NS yeti-ns.conit.co
yeti-ns.conit.co 3600000 IN AAAA \
2604:6600:2000:11::4854:a010
. 3600000 IN NS dahu2.yeti.eu.org
dahu2.yeti.eu.org 3600000 IN AAAA 2001:67c:217c:6::2
. 3600000 IN NS yeti.aquaray.com
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yeti.aquaray.com 3600000 IN AAAA 2a02:ec0:200::1
. 3600000 IN NS yeti-ns.switch.ch
yeti-ns.switch.ch 3600000 IN AAAA 2001:620:0:ff::29
. 3600000 IN NS yeti-ns.lab.nic.cl
yeti-ns.lab.nic.cl 3600000 IN AAAA 2001:1398:1:21::8001
. 3600000 IN NS yeti-ns1.dns-lab.net
yeti-ns1.dns-lab.net 3600000 IN AAAA 2001:da8:a3:a027::6
. 3600000 IN NS yeti-ns2.dns-lab.net
yeti-ns2.dns-lab.net 3600000 IN AAAA 2001:da8:268:4200::6
. 3600000 IN NS yeti-ns3.dns-lab.net
yeti-ns3.dns-lab.net 3600000 IN AAAA 2400:a980:30ff::6
. 3600000 IN NS \
ca978112ca1bbdcafac231b39a23dc.yeti-dns.net
ca978112ca1bbdcafac231b39a23dc.yeti-dns.net \
3600000 IN AAAA 2c0f:f530::6
. 3600000 IN NS \
3e23e8160039594a33894f6564e1b1.yeti-dns.net
3e23e8160039594a33894f6564e1b1.yeti-dns.net \
3600000 IN AAAA 2803:80:1004:63::1
. 3600000 IN NS \
3f79bb7b435b05321651daefd374cd.yeti-dns.net
3f79bb7b435b05321651daefd374cd.yeti-dns.net \
3600000 IN AAAA 2401:c900:1401:3b:c::6
. 3600000 IN NS \
xn--r2bi1c.xn--h2bv6c0a.xn--h2brj9c
xn--r2bi1c.xn--h2bv6c0a.xn--h2brj9c \
3600000 IN AAAA 2001:e30:1c1e:10::333
. 3600000 IN NS yeti1.ipv6.ernet.in
yeti1.ipv6.ernet.in 3600000 IN AAAA 2001:e30:187d::333
. 3600000 IN NS yeti-dns02.dnsworkshop.org
yeti-dns02.dnsworkshop.org \
3600000 IN AAAA 2001:19f0:0:1133::53
. 3600000 IN NS yeti.mind-dns.nl
yeti.mind-dns.nl 3600000 IN AAAA 2a02:990:100:b01::53:0
Appendix B. Controversy
The Yeti DNS Project, its infrastructure and the various experiments
that have been carried out using that infrastructure, have been
described by people involved in the project in many public meetings
at technical venues since its inception. The mailing lists using
which the operation of the infrastructure has been coordinated are
open to join, and their archives are public. The project as a whole
has been the subject of robust public discussion.
Some commentators have expressed concern that the Yeti DNS Project
is, in effect, operating an "alternate root," challenging the IAB's
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comments published in [RFC2826]. Other such alternate roots are
considered to have caused end-user confusion and instability in the
namespace of the DNS by the introduction of new top-level labels or
the different use of top-level labels present in the Root Server
System. The coordinators of the Yeti DNS Project do not consider the
Yeti DNS Project to be an alternate root in this sense, since by
design the namespace enabled by the Yeti-Root Zone is identical to
that of the Root Zone.
Some commentators have expressed concern that the Yeti DNS Project
seeks to influence or subvert administrative policy relating to the
Root Server System, in particular in the use of DNSSEC trust anchors
not published by the IANA and the use of Yeti-Root Servers in regions
where governments or other organisations have expressed interest in
operating a Root Server. The coordinators of the Yeti-Root project
observe that their mandate is entirely technical and has no ambition
to influence policy directly; they do hope, however, that technical
findings from the Yeti DNS Project might act as a useful resource for
the wider technical community.
Finally, some concern has been expressed about the possible
applications of the Yeti DNS Project to the governments of countries
where access to the Internet is subject to substantial centralised
control, in contrast to most other jurisdictions where such controls
are either lighter or not present. The coordinators of the Yeti DNS
Project have taken care to steer all discussions and related
decisions about the technical work of the project to public venues in
the interests of full transparency, and encourage anybody concerned
about the decision-making process to participate in those venues and
review their archives directly.
Appendix C. About This Document
This section (and sub-sections) has been included as an aid to
reviewers of this document, and should be removed prior to
publication.
C.1. Venue
The authors propose that this document proceeed as an Independent
Submission, since it documents work that, although relevant to the
IETF, has been carried out externally to any IETF working group.
However, a suitable venue for discussion of this document is the
dnsop working group.
Information about the Yeti DNS project and discussion relating to
particular experiments described in this document can be found at
<https://yeti-dns.org/>.
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This document is maintained in GitHub at <https://github.com/BII-Lab/
yeti-testbed-experience>.
C.2. Revision History
C.2.1. draft-song-yeti-testbed-experience-00 through -03
Change history is available in the public GitHub repository where
this document is maintained: <https://github.com/BII-Lab/yeti-
testbed-experience>.
C.2.2. draft-song-yeti-testbed-experience-04
Substantial editorial review and rearrangement of text by Joe Abley
at request of BII.
Added what is intended to be a balanced assessment of the controversy
that has arisen around the Yeti DNS Project, at the request of the
Independent Submissions Editorial Board.
Changed the focus of the document from the description of individual
experiments on a Root-like testbed to the construction and
motivations of the testbed itself, since that better describes the
output of the Yeti DNS Project to date. In the considered opinion of
this reviewer, the novel approaches taken in the construction of the
testbed infrastructure and the technical challenges met in doing so
are useful to record, and the RFC series is a reasonable place to
record operational experiences related to core Internet
infrastructure.
Note that due to draft cut-off deadlines some of the technical
details described in this revision of the document may not exactly
match operational reality; however, this revision provides an
indicative level of detail, focus and flow which it is hoped will be
helpful to reviewers.
Authors' Addresses
Linjian Song (editor)
Beijing Internet Institute
2508 Room, 25th Floor, Tower A, Time Fortune
Beijing 100028
P. R. China
Email: songlinjian@gmail.com
URI: http://www.biigroup.com/
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Dong Liu (editor)
Beijing Internet Institute
2508 Room, 25th Floor, Tower A, Time Fortune
Beijing 100028
P. R. China
Email: dliu@biigroup.com
URI: http://www.biigroup.com/
Paul Vixie (editor)
TISF
11400 La Honda Road
Woodside, California 94062
US
Email: vixie@tisf.net
URI: http://www.redbarn.org/
Akira Kato (editor)
Keio University/WIDE Project
Graduate School of Media Design, 4-1-1 Hiyoshi, Kohoku
Yokohama 223-8526
JAPAN
Email: kato@wide.ad.jp
URI: http://www.kmd.keio.ac.jp/
Shane Kerr
Antoon Coolenlaan 41
Uithoorn 1422 GN
NL
Email: shane@time-travellers.org
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