Outsourcing Home Network Authoritative Naming Service
draft-ietf-homenet-front-end-naming-delegation-10
The information below is for an old version of the document.
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| Authors | Daniel Migault , Ralf Weber , Michael Richardson , Ray Hunter , Chris Griffiths , Wouter Cloetens | ||
| Last updated | 2020-03-09 (Latest revision 2019-11-16) | ||
| Replaces | draft-mglt-homenet-front-end-naming-delegation | ||
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draft-ietf-homenet-front-end-naming-delegation-10
Homenet D. Migault
Internet-Draft Ericsson
Intended status: Informational R. Weber
Expires: September 10, 2020 Nominum
M. Richardson
Sandelman Software Works
R. Hunter
Globis Consulting BV
C. Griffiths
W. Cloetens
SoftAtHome
March 09, 2020
Outsourcing Home Network Authoritative Naming Service
draft-ietf-homenet-front-end-naming-delegation-10
Abstract
The Homenet Naming authority is responsible for making devices within
the home network accessible by name within the home network as well
as from outside the home network (e.g. the Internet). The names of
the devices accessible from the Internet are stored in the Public
Homenet Zone, served by a DNS authoritative server. It is unlikely
that home networks will contain sufficiently robust platforms
designed to host a service such as the DNS on the Internet and as
such would expose the home network to DDoS attacks.
This document describes a mechanism that enables the Home Network
Authority (HNA) to outsource the naming service to the Outsourcing
Infrastructure via a Distribution Master (DM).
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."
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This Internet-Draft will expire on September 10, 2020.
Copyright Notice
Copyright (c) 2020 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
1.1. Alternative solutions . . . . . . . . . . . . . . . . . . 5
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Architecture Description . . . . . . . . . . . . . . . . . . 8
3.1. Architecture Overview . . . . . . . . . . . . . . . . . . 8
3.2. Distribution Master Communication Channels . . . . . . . 10
4. Control Channel between HNA and DM . . . . . . . . . . . . . 11
4.1. Information to build the Public Homenet Zone. . . . . . . 11
4.2. Information to build the DNSSEC chain of trust. . . . . . 12
4.3. Information to set the Synchronization Channel, . . . . . 12
4.4. Deleting the delegation . . . . . . . . . . . . . . . . . 13
4.5. Messages Exchange Description . . . . . . . . . . . . . . 13
4.5.1. Retrieving information for the Public Homenet Zone. . 13
4.5.2. Providing information for the DNSSEC chain of trust . 14
4.5.3. Providing information for the Synchronization Channel 14
4.5.4. HNA instructing deleting the delegation . . . . . . . 15
4.6. Securing the Control Channel between HNA and DM . . . . . 15
4.7. Implementation Tips . . . . . . . . . . . . . . . . . . . 16
5. DM Synchronization Channel between HNA and DM . . . . . . . . 17
5.1. Securing the Synchronization Channel between HNA and DM . 18
6. DM Distribution Channel . . . . . . . . . . . . . . . . . . . 18
7. HNA Security Policies . . . . . . . . . . . . . . . . . . . . 18
8. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 19
9. Homenet Reverse Zone . . . . . . . . . . . . . . . . . . . . 19
10. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 20
10.1. Hidden Primary . . . . . . . . . . . . . . . . . . . . . 21
10.2. Distribution Master . . . . . . . . . . . . . . . . . . 22
11. Operational considerations for Offline/Disconnected
resolution . . . . . . . . . . . . . . . . . . . . . . . . . 22
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12. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22
13. Security Considerations . . . . . . . . . . . . . . . . . . . 23
13.1. HNA DM channels . . . . . . . . . . . . . . . . . . . . 23
13.2. Names are less secure than IP addresses . . . . . . . . 24
13.3. Names are less volatile than IP addresses . . . . . . . 24
13.4. DNS Reflection Attacks . . . . . . . . . . . . . . . . . 24
13.5. Reflection Attack involving the Hidden Primary . . . . . 25
13.6. Reflection Attacks involving the DM . . . . . . . . . . 26
13.7. Reflection Attacks involving the Public Authoritative
Servers . . . . . . . . . . . . . . . . . . . . . . . . 27
13.8. Flooding Attack . . . . . . . . . . . . . . . . . . . . 27
13.9. Replay Attack . . . . . . . . . . . . . . . . . . . . . 27
14. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
15. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 28
16. Annex . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
16.1. Envisioned deployment scenarios . . . . . . . . . . . . 29
16.1.1. CPE Vendor . . . . . . . . . . . . . . . . . . . . . 29
16.1.2. Agnostic CPE . . . . . . . . . . . . . . . . . . . . 29
16.2. Example: Homenet Zone . . . . . . . . . . . . . . . . . 30
16.3. Example: HNA necessary parameters for outsourcing . . . 32
17. References . . . . . . . . . . . . . . . . . . . . . . . . . 33
17.1. Normative References . . . . . . . . . . . . . . . . . . 33
17.2. Informative References . . . . . . . . . . . . . . . . . 37
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37
1. Introduction
The Homenet Naming authority is responsible for making devices within
the home network accessible by name within the home network as well
as from outside the home network (e.g. the Internet). IPv6
connectivity provides the possibility of global end to end IP
connectivity. End users will be able to transparently make use of
this connectivity if they can use names to access the services they
want from their home network.
The use of a DNS zone for each home network is a reasonable and
scalable way to make the set of public names visible. There are a
number of ways to populate such a zone. This specification proposes
a way to do with based upon a number of assumptions about typical
home networks.
1. The names of the devices accessible from the Internet are stored
in the Public Homenet Zone, served by a DNS authoritative server.
2. It is unlikely that home networks will contain sufficiently
robust platforms designed to host a service such as the DNS on
the Internet and as such would expose the home network to DDoS
attacks.
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3. [RFC7368] emphazes that the home network is subject to
connectivity disruptions with the ISP. But, names used within
the home MUST be resilient against such disruption.
So a goal of this specification is to make the public names
resolvable within both the home network and on the Internet, even
when there are disruptions.
This is achieved by having a device inside the home network that
builds, publishes, and manages a Public Homenet Zone, thus providing
bindings between public names, IP addresses, and other RR types.
The management of the names can be a role that the Customer Premises
Equipment (CPE) does. Other devices in the home network could
fulfill this role e.g. a NAS server, but for simplicity, this
document assumes the function is located on one of the CPE devices.
The homenet architecture [RFC7368] makes it clear that a home network
may have multiple CPEs. The management of the Public Homenet Zone
involves DNS specific mechanisms that cannot be distributed over
multiple servers (primary server), when multiple nodes can
potentially manage the Public Homenet Zone, a single node needs to be
selected per outsourced zone. This selected node is designated as
providing the Homenet Naming Authority (HNA) function.
The process by which a single HNA is selected per zone is not in
scope for this document. It is envisioned that a future document
will describe an HNCP mechanism to elect the single HNA.
CPEs, which may host the HNA function, as well as home network
devices, are usually low powered devices not designed for terminating
heavy traffic. As a result, hosting an authoritative DNS service
visible to the Internet may expose the home network to resource
exhaustion and other attacks. On the other hand, if the only copy of
the public zone is on the Internet, then Internet connectivity
disruptions would make the names unavailable inside the homenet.
In order to avoid resource exhaustion and other attacks, this
document describes an architecture that outsources the authoritative
naming service of the home network. More specifically, the HNA
builds the Public Homenet Zone and outsources it to an Outsourcing
Infrastructure via a Distribution Master (DM). The Outsourcing
Infrastructure is in charge of publishing the corresponding Public
Homenet Zone on the Internet. The transfer of DNS zone information
is achieved using standard DNS mechanisms involving primary and
secondary DNS servers, with the HNA hosted primary being a stealth
primary, and the Distribution Master a secondary.
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Section 3.1 provides an architecture description that describes the
relation between the HNA and the Outsourcing Architecture. In order
to keep the Public Homenet Zone up-to-date Section 5 describes how
the HNA and the Outsourcing Infrastructure synchronizes the Pubic
Homenet Zone.
The proposed architecture is explicitly designed to enable fully
functional DNSSEC, and the Public Homenet Zone is expected to be
signed with a secure delegation. DNSSEC key management and zone
signing is handled by the HNA.
Section 9 discusses management of one or more reverse zones. It
shows that management of the reverse zones can be entirely automated
and benefit from a pre-established relation between the ISP and the
home network. Note that such scenarios may also be met for the
Public Homenet Zone, but not necessarily.
Section 10 discusses how renumbering should be handled. Finally,
Section 12 and Section 13 respectively discuss privacy and security
considerations when outsourcing the Public Homenet Zone.
The Public Homenet Zone is expected to contain public information
only in a single universal view. This document does not define how
the information required to construct this view is derived.
It is also not in the scope of this document to define names for
exclusive use within the boundaries of the local home network.
Instead, local scope information is expected to be provided to the
home network using local scope naming services. mDNS [RFC6762] DNS-SD
[RFC6763] are two examples of these services. Currently mDNS is
limited to a single link network. However, future protocols and
architectures [I-D.ietf-homenet-simple-naming] are expected to
leverage this constraint as pointed out in [RFC7558].
1.1. Alternative solutions
An alternative existing solution in IPv4 is to have a single zone,
where a host uses a RESTful HTTP service to register a single name
into a common public zone. This is often called "Dynamic DNS", and
there are a number of commercial providers, including Dyn, Gandi etc.
These solutions were typically used by a host behind the CPE to make
it's CPE IPv4 address visible, usually in order to enable incoming
connections.
For a small number (one to three) of hosts, use of such a system
provides an alternative to the architecture described in this
document.
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The alternative does suffer from some severe limitations:
o the CPE/HNA router is unaware of the process, and cannot respond
to queries for these names when there are disruptions in
connectivity. This makes the home user or application dependent
on having to resolve different names in the event of outages or
disruptions.
o the CPE/HNA router cannot control the process. Any host can do
this regardless of whether or not the home network administrator
wants the name published or not. There is therefore no possible
audit trail.
o the credentials for the dynamic DNS server need to be securely
transferred to all hosts that wish to use it. This is not a
problem for a technical user to do with one or two hosts, but it
does not scale to multiple hosts and becomes a problem for non-
technical users.
o "all the good names are taken" - current services put everyone's
names into some small set of zones, and there are often conflicts.
Distinguishing similar names by delegation of zones was among the
primary design goals of the DNS system.
o The RESTful services do not always support all RR types. The
homenet user is dependent on the service provider supporting new
types. By providing full DNS delegation, this document enables
all RR types and also future extensions.
There is no technical reason why a RESTful cloud service could not
provide solutions to many of these problems, but this document
describes a DNS based solution.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
o Customer Premises Equipment: (CPE) is a router providing
connectivity to the home network.
o Homenet Zone: is the DNS zone for use within the boundaries of the
home network: home.arpa, see [RFC8375]). This zone is not
considered public and is out of scope for this document.
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o Registered Homenet Domain: is the Domain Name associated with the
home network.
o Public Homenet Zone: contains the names in the home network that
are expected to be publicly resolvable on the Internet.
o Homenet Naming Authority: (HNA) is a function responsible for
managing the Public Homenet Zone. This includes populating the
Public Homenet Zone, signing the zone for DNSSEC, as well as
managing the distribution of that Homenet Zone to the Outsourcing
Infrastructure.
o Outsourcing Infrastructure: is the infrastructure responsible for
receiving the Public Homenet Zone and publishing it on the
Internet. It is mainly composed of a Distribution Master and
Public Authoritative Servers.
o Public Authoritative Servers: are the authoritative name servers
for the Public Homenet Zone. Name resolution requests for the
Homenet Domain are sent to these servers. For resiliency the
Public Homenet Zone SHOULD be hosted on multiple servers.
o Homenet Authoritative Servers: are authoritative name servers
within the Homenet network.
o Distribution Master (DM): is the (set of) server(s) to which the
HNA synchronizes the Public Homenet Zone, and which then
distributes the relevant information to the Public Authoritative
Servers.
o Homenet Reverse Zone: The reverse zone file associated with the
Public Homenet Zone.
o Reverse Public Authoritative Servers: equivalent to Public
Authoritative Servers specifically for reverse resolution.
o Reverse Distribution Master: equivalent to Distribution Master
specifically for reverse resolution.
o Homenet DNSSEC Resolver: a resolver that performs a DNSSEC
resolution on the home network for the Public Homenet Zone. The
resolution is performed requesting the Homenet Authoritative
Servers.
o DNSSEC Resolver: a resolver that performs a DNSSEC resolution on
the Internet for the Public Homenet Zone. The resolution is
performed requesting the Public Authoritative Servers.
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3. Architecture Description
This section provides an overview of the architecture for outsourcing
the authoritative naming service from the HNA to the Outsourcing
Infrastructure in Section 3.1. Section Section 16.2 and Section 16.3
illustrates this architecture with the example of a Public Homenet
Zone as well as necessary parameter to configure the HNA.
3.1. Architecture Overview
Figure Figure 1 illustrates the architecture where the HNA outsources
the publication of the Public Homenet Zone to the Outsourcing
Infrastructure.
The Public Homenet Zone is identified by the Registered Homenet
Domain Name - example.com.
".local" as well as ".home.arpa" are explicitly not considered as
Public Homenet zones.
The HNA SHOULD build the Public Homenet Zone in a single view
populated with all resource records that are expected to be published
on the Internet.
How the Public Homenet Zone is populated is out of the scope of this
document. The node providing the HNA function may also host or
interact with multiple services to determine name-to-address
mappings, such as a web GUI, DHCP [RFC6644] or mDNS [RFC6762]. These
services may coexist and may be used to populate the Public Homenet
Zone.
The HNA also signs the Public Homenet Zone. The HNA handles all
operations and keying material required for DNSSEC, so there is no
provision made in this architecture for transferring private DNSSEC
related keying material between the HNA and the DM.
Once the Public Homenet Zone has been built, the HNA outsources it to
the Outsourcing Infrastructure as described in Figure 1.
The HNA acts as a hidden primary while the DM behaves as a secondary
responsible to distribute the Public Homenet Zone to the multiple
Public Authoritative Servers that Outsourcing Infrastructure is
responsible for.
The DM has 3 communication channels: * a DM Control Channel (see
section Section 4) to configure the HNA and the Outsourcing
Infrastructure, * a DM Synchronization Channel (see section Section 5
to synchronize the Public Homenet Zone on the HNA and on the DM. *
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one or more Distribution Channels (see section Section 6 that
distributes the Public Homenet Zone from the DM to the Public
Authoritative Server serving the Public Homenet Zone on the Internet.
There MAY be multiple DM's, and multiple servers per DM. This text
assumes a single DM server for simplicity, but there is no reason why
each channel need to be implemented on the same server, or indeed use
the same code base.
It is important to note that while the HNA is configured as an
authoritative server, it is not expected to answer to DNS requests
from the public Internet for the Public Homenet Zone. The function
of the HNA is limited to building the zone and synchronization with
the DM.
The addresses associated with the HNA SHOULD NOT be mentioned in the
NS records of the Public Homenet zone, unless additional security
provisions necessary to protect the HNA from external attack have
been taken.
The Outsourcing Infrastructure is also responsible for ensuring the
DS record has been updated in the parent zone.
Resolution is performed by the DNSSEC resolvers. When the resolution
is performed outside the home network, the DNSSEC Resolver resolves
the DS record on the Global DNS and the name associated to the Public
Homenet Zone (example.com) on the Public Authoritative Servers.
When the resolution is performed from within the home network, the
Homenet DNSSEC Resolver may proceed similarly. On the other hand, to
provide resilience to the Public Homenet Zone in case of disruption,
the Homenet DNSSEC Resolver SHOULD be able to perform the resolution
on the authoritative name service of the home network implemented by
the Homenet Authoritative Servers. These servers are not expected to
be mentioned in the Public Homenet Zone, nor to be accessible from
the Internet. As such their information as well as the corresponding
signed DS record MAY be provided by the HNA to the Homenet DNSSEC
Resolvers e.g. using HNCP. Such configuration is outside the scope
of this document.
How the Homenet Authoritative Servers are provisioned is also out of
scope of this specification. It could be implemented using primary
secondaries servers, or via rsync. In some cases, the HNA and
Homenet Authoritative Servers may be combined together which would
result in a common instantiation of an authoritative server on the
WAN and inner interface. Other mechanisms may also be used.
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Home network | Internet
|
| +----------------------------+
| | Outsourcing Infrastructure |
Control | | |
+-----------------------+Channel | | +-----------------------+ |
| HNA |<-------------->| Distribution Master | |
|+---------------------+| | | |+---------------------+| |
|| Public Homenet Zone ||Synchronization || Public Homenet Zone || |
|| (example.com) ||Channel | | || (example.com) || |
|+---------------------+|<-------------->|+---------------------+| |
+----------------------+| | | +-----------------------+ |
| | ^ Distribution |
| | | Channel |
+-----------------------+ | | v |
| Homenet Authoritative | | | +-----------------------+ |
| Server(s) | | | | Public Authoritative | |
|+---------------------+| | | | Server(s) | |
||Public Homenet Zone || | | |+---------------------+| |
|| (example.com) || | | || Public Homenet Zone || |
|+---------------------+| | | || (example.com) || |
+-----------------------+ | | |+---------------------+| |
^ | | | +-----------------------+ |
| | | +----------^---|-------------+
| | | | |
| | name resolution | |
| v | | v
+----------------------+ | +-----------------------+
| Homenet | | | Internet |
| DNSSEC Resolver | | | DNSSEC Resolver |
+----------------------+ | +-----------------------+
Figure 1: Homenet Naming Architecture Name Resolution
3.2. Distribution Master Communication Channels
This section details the interfaces and channels of the DM, that is
the Control Channel, the Synchronization Channel and the Distribution
Channel.
The Control Channel and the Synchronization Channel are the
interfaces used between the HNA and the Outsourcing Infrastructure.
The entity within the Outsourcing Infrastructure responsible to
handle these communications is the DM and communications between the
HNA and the DM SHOULD be protected and mutually authenticated. While
section Section 4.6 discusses in more depth the different security
protocols that could be used to secure, this specification RECOMMENDS
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the use of TLS with mutually authentication based on certificates to
secure the channel between the HNA and the DM.
The Control Channel is used to set up the Synchronization Channel.
We assume that the HNA initiates the Control Channel connection with
the DM and as such has a prior knowledge of the DM identity (X509
certificate), the IP address and port to use and protocol to set
secure session. We also assume the DM has knowledge of the identity
of the HNA (X509 certificate) as well as the Registered Homenet
Domain.
The information exchanged between the HNA and the DM is using DNS
messages. DNS messages can be protected using various kind of
transport layers, among others, UDP:53/DTLS, TLS/TCP:53, HTTPS:443.
There was consideration to using a standard TSIG [RFC2845] or SIG(0)
[RFC2931] to perform a dynamic DNS update to the DM. There are a
number of issues with this. The main one is that the Dynamic DNS
update would also update the zone's NS records, while the goal is to
update the Distribution Master's configuration files. The visible NS
records SHOULD remain pointing at the cloud provider's anycast
addresses. Revealing the address of the HNA in the DNS is not
desireable.
This specification also assumes the same transport protocol and ports
used by the DM to serve the Control Channel and by the HNA to serve
the Synchronization Channel are the same.
The Distribution Channel is internal to the Outsourcing
Infrastructure and as such is not the primary concern of this
specification.
4. Control Channel between HNA and DM
The DM Control Channel is used by the HNA and the Outsourcing
Infrastructure to exchange information related to the configuration
of the delegation which includes:
4.1. Information to build the Public Homenet Zone.
More specifically, the Public Homenet Zone contains information that
is related to the infrastructure serving the zone. In our case, the
infrastructure serving the Public Homenet Zone is the Outsourcing
Infrastructure, so this information MUST reflect that Outsourcing
Infrastructure and MUST be provided to the HNA.
The information includes at least names and IP addresses of the
Public Authoritative Servers. In term of RRset information this
corresponds, for the Registered Homenet Domain the MNAME of the SOA,
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the NS and associated A and AAA RRsets. Optionally the Outsourcing
Infrastructure MAY also provide operational parameters such as other
fields of SOA (SERIAL, RNAME, REFRESH, RETRY, EXPIRE and MINIMUM).
As the information is necessary for the HNA to proceed and the
information is associated to the Outsourcing Infrastructure, this
information exchange is mandatory.
4.2. Information to build the DNSSEC chain of trust.
The HNA SHOULD provide the hash of the KSK (DS RRset), so the that
Outsourcing Infrastructure provides this value to the parent zone. A
common deployment use case is that the Outsourcing Infrastructure is
the registrar of the Registered Homenet Domain, and as such, its
relationship with the registry of the parent zone enables it to
update the parent zone. When such relation exists, the HNA should be
able to request the Outsourcing Infrastructure to update the DS RRset
in the parent zone. A direct update is especially necessary to
initialize the chain of trust.
Though the HNA may also later directly update the values of the DS
via the Control Channel, it is RECOMMENDED to use other mechanisms
such as CDS and CDNSKEY [RFC7344] are used for key roll overs.
As some deployment may not provide an Outsourcing Infrastructure that
will be able to update the DS in the parent zone, this information
exchange is OPTIONAL.
By accepting the DS, the DM commits in taking care of advertising the
DS to the parent zone. Upon refusal, the DM MUST clearly indicate
the DM does not have the capacity to proceed to the update.
4.3. Information to set the Synchronization Channel,
That information sets the primary/secondary relation between the HNA
and the DM. The HNA works as a primary authoritative DNS server, and
MUST provide the corresponding IP address.
The specified IP address on the HNA side and the currently used IP
address of the DM defines the IP addresses involved in the
Synchronization Channel. Ports and transport protocol are the same
as those used by the Control Channel. By default, the same IP
address used by the HNA is considered by the DM. Exchange of this
information is OPTIONAL.
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4.4. Deleting the delegation
The purpose of the previous sections were to exchange information in
order to set a delegation. The HNA MUST also be able to delete a
delegation with a specific DM. Upon an instruction of deleting the
delegation, the DM MUST stop serving the Public Homenet Zone.
4.5. Messages Exchange Description
There are multiple ways these information could be exchanged between
the HNA and the DM. This specification defines a mechanism that re-
use the DNS exchanges format. The intention is to reuse standard
libraries especially to check the format of the exchanged fields as
well as to minimize the additional libraries needed for the HNA. The
re-use of DNS exchanges achieves these goals. Note that while
information is provided using DNS exchanges, the exchanged
information is not expected to be set in any zone file, instead this
information is expected to be processed appropriately.
The Control Channel is not expected to be a long term session. After
a predefined timer the Control Channel is expected to be terminated.
The Control Channel MAY Be re-opened at any time later.
The provisioning process SHOULD provide a method of securing the
control channel, so that the content of messages can be
authenticated. This authentication MAY be based on certificates for
both the DM and each HNA. The DM may also create the initial
configuration for the delegation zone in the parent zone during the
provisioning process.
4.5.1. Retrieving information for the Public Homenet Zone.
The information provided by the DM to the HNA is retrieved by the HNA
with a AXFR exchange. The AXFR message enables the response to
contain any type of RRsets. The response might be extended in the
future if additional information will be needed. Alternatively, the
information provided by the HNA to the DM is pushed by the HNA via a
DNS update exchange.
To retrieve the necessary information to build the Public Homenet
Zone, the HNA MUST send an DNS request of type AXFR associated to the
Registered Homenet Domain. The DM MUST respond with a zone template.
The zone template MUST contain a RRset of type SOA, one or multiple
RRset of type NS and at least one RRset of type A or AAAA. The SOA
RR is used to indicate to the HNA the value of the MNAME of the
Public Homenet Zone. The NAME of the SOA RR MUST be the Registered
Homenet Domain. The MNAME value of the SOA RDATA is the value
provided by the Outsourcing Infrastructure to the HNA. Other RDATA
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values (RNAME, REFRESH, RETRY, EXPIRE and MINIMUM) are provided by
the Outsourcing Infrastructure as suggestions. The NS RRsets are
used to carry the Public Authoritative Servers of the Outsourcing
Infrastructure. Their associated NAME MUST be the Registered Homenet
Domain. The TTL and RDATA are those expected to be published on the
Public Homenet Zone. The RRsets of Type A and AAAA MUST have their
NAME matching the NSDNAME of one of the NS RRsets.
Upon receiving the response, the HNA MUST validate the conditions on
the SOA, NS and A or AAAA RRsets. If an error occurs, the HNA MUST
stop proceeding and MUST report an error. Otherwise, the HNA builds
the Public Homenet Zone by setting the MNAME value of the SOA as
indicated by the SOA provided by the AXFR response. The HNA SHOULD
set the value of NAME, REFRESH, RETRY, EXPIRE and MINIMUM of the SOA
to those provided by the AXFR response. The HNA MUST insert the NS
and corresponding A or AAAA RRset in its Public Homenet Zone. The
HNA MUST ignore other RRsets. If an error message is returned by the
DM, the HNA MUST proceed as a regular DNS resolution. Error messages
SHOULD be logged for further analysis. If the resolution does not
succeed, the outsourcing operation is aborted and the HNA MUST close
the Control Channel.
4.5.2. Providing information for the DNSSEC chain of trust
To provide the DS RRset to initialize the DNSSEC chain of trust the
HNA MAY send a DNS UPDATE [RFC2136] message. The NAME in the SOA
MUST be set to the parent zone of the Registered Homenet Domain -
that is where the DS records should be inserted. The DS RRset MUST
be placed in the Update section of the UPDATE query, and the NAME
SHOULD be set to the Registered Homenet Domain. The rdata of the DS
RR SHOULD correspond to the DS record to be inserted in the parent
zone.
A NOERROR response from the MD is a commitment to update the parent
zone with the provided DS. An error indicates the MD will not update
the DS, and other method should be used by the HNA.
4.5.3. Providing information for the Synchronization Channel
To provide the IP address of the primary, the HNA MAY send a DNS
UPDATE message. The NAME in the SOA MUST be the parent zone of the
Registered Homenet Domain. The Update section MUST be a RRset of
Type NS. The NAME associated to the NS RRSet MUST be the Registered
Domain Name. The RDATA MUST be a FQDN that designates the IP
addresses associated to the primary. There may be multiple IP
addresses. These IP addresses MUST be provided in the additional
section. The reason to provide these IP addresses is that it is NOT
RECOMMENDED to publish these IP addresses. As a result, it is not
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expected to resolve them. IP addresses are provided via RRsets of
type A or AAAA. The NAME associated to RRsets of type A and AAAA
MUST be the Registered Homenet Domain.
A NOERROR response indicates the DM has configured the secondary and
is committed to serve as a secondary. An error indicates the DM is
not configured as a secondary.
The regular DNS error message SHOULD be returned to the HNA when an
error occurs. In particular a FORMERR is returned when a format
error is found, this error includes when unexpected RRSets are added
or when RRsets are missing. A SERVFAIL error is returned when a
internal error is encountered. a NOTZONE error is returned when
update and Zone sections are not coherent, a NOTAUTH error is
returned when the DM is not authoritative for the Zone section. A
REFUSED error is returned when the DM refuses to proceed to the
configuration and the requested action.
4.5.4. HNA instructing deleting the delegation
To instruct to delete the delegation the HNA MAY send a DNS UPDATE
Delete message. The NAME in the SOA MUST be the parent zone of the
Registered Homenet Domain. The Update section MUST be a RRset of
Type NS. The NAME associated to the NS RRSet MUST be the Registered
Domain Name. As indictaed by [RFC2136] section 2.5.2 the delete
instruction is set by setting the TTL to 0, the CLass to ANY, the
RDLENGTH to 0 and the RDATA MUST be empty.
4.6. Securing the Control Channel between HNA and DM
The control channel between the HNA and the DM MUST be secured at
both the HNA and the DM.
Secure protocols (like TLS [RFC5246] / DTLS [RFC6347]) SHOULD be used
to secure the transactions between the DM and the HNA.
The advantage of TLS/DTLS is that this technology is widely deployed,
and most of the devices already embed TLS/DTLS libraries, possibly
also taking advantage of hardware acceleration. Further, TLS/DTLS
provides authentication facilities and can use certificates to
authenticate the DM and the HNA. On the other hand, using TLS/DTLS
requires implementing DNS exchanges over TLS/DTLS, as well as a new
service port. This document RECOMMENDS this option.
The HNA SHOULD authenticate inbound connections from the DM using
standard mechanisms, such as a public certificate with baked-in root
certificates on the HNA, or via DANE {!RFC6698}}.
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The DM SHOULD authenticate the HNA and check that inbound messages
are from the appropriate client. The DM MAY use a self-signed CA
certificate mechanism per HNA, or public certificates for this
purpose.
IPsec [RFC4301] IKEv2 [RFC7296] MAY also be used to secure
transactions between the HNA and the DM. Similarly to TLS/DTLS, most
HNAs already embed an IPsec stack, and IKEv2 supports multiple
authentication mechanisms via the EAP framework. In addition, IPsec
can be used to protect DNS exchanges between the HNA and the DM
without any modifications of the DNS server or client. DNS
integration over IPsec only requires an additional security policy in
the Security Policy Database (SPD). One disadvantage of IPsec is
that NATs and firewall traversal may be problematic. However, in our
case, the HNA is connected to the Internet, and IPsec communication
between the HNA and the DM should not be impacted by middle boxes.
How the PSK can be used by any of the TSIG, TLS/DTLS or IPsec
protocols: Authentication based on certificates implies a mutual
authentication and thus requires the HNA to manage a private key, a
public key, or certificates, as well as Certificate Authorities.
This adds complexity to the configuration especially on the HNA side.
For this reason, we RECOMMEND that the HNA MAY use PSK or certificate
based authentication, and that the DM MUST support PSK and
certificate based authentication.
Note also that authentication of message exchanges between the HNA
and the DM SHOULD NOT use the external IP address of the HNA to index
the appropriate keys. As detailed in Section 10, the IP addresses of
the DM and the Hidden Primary are subject to change, for example
while the network is being renumbered. This means that the necessary
keys to authenticate transaction SHOULD NOT be indexed using the IP
address, and SHOULD be resilient to IP address changes.
4.7. Implementation Tips
The Hidden Primary Server on the HNA differs from a regular
authoritative server for the home network due to:
o Interface Binding: the Hidden Primary Server will almost certainly
listen on the WAN Interface, whereas a regular authoritative
server for the home network would listen on the internal home
network interface.
o Limited exchanges: the purpose of the Hidden Primary Server is to
synchronize with the DM, not to serve any zones to end users, or
the public Internet.
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As a result, exchanges are performed with specific nodes (the DM).
Further, exchange types are limited. The only legitimate exchanges
are: NOTIFY initiated by the Hidden Primary and IXFR or AXFR
exchanges initiated by the DM. On the other hand, regular
authoritative servers would respond to any hosts, and any DNS query
would be processed. The HNA SHOULD filter IXFR/AXFR traffic and drop
traffic not initiated by the DM. The HNA MUST listen for DNS on TCP
and UDP and MUST at least allow SOA lookups of the Homenet Zone.
5. DM Synchronization Channel between HNA and DM
The DM Synchronization Channel is used for communication between the
HNA and the DM for synchronizing the Public Homenet Zone. Note that
the Control Channel and the Synchronization Channel are by
construction different channels even though there they MAY use the
same IP addresses. In fact the Control Channel is set between the
HNA working as a client using port YYYY (a high range port) toward a
service provided by the MD at port XX (well known port). On the
other hand, the Synchronization Channel is set between the MD working
as a client using port ZZZZ ( a high range port) toward a service a
service provided by the HNA at port XX. As a result, even though the
same couple of IP addresses may be involved the Control Channel and
the Synchronization Channel are always disc tint channels.
Uploading and dynamically updating the zone file on the DM can be
seen as zone provisioning between the HNA (Hidden Primary) and the DM
(Secondary Server). This can be handled via AXFR + DNS UPDATE.
This document RECOMMENDS use of a primary / secondary mechanism
instead of the use of DNS UPDATE. The primary / secondary mechanism
is RECOMMENDED as it scales better and avoids DoS attacks. Note that
even when UPDATE messages are used, these messages are using a
distinct channel as those used to set the configuration.
Note that there is no standard way to distribute a DNS primary
between multiple devices. As a result, if multiple devices are
candidate for hosting the Hidden Primary, some specific mechanisms
should be designed so the home network only selects a single HNA for
the Hidden Primary. Selection mechanisms based on HNCP [RFC7788] are
good candidates.
The HNA acts as a Hidden Primary Server, which is a regular
authoritative DNS Server listening on the WAN interface.
The DM is configured as a secondary for the Homenet Domain Name.
This secondary configuration has been previously agreed between the
end user and the provider of the Outsourcing Infrastructure as part
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of either the provisioning or due to receipt of UPDATE messages on
the DM Control Channel.
The Homenet Reverse Zone MAY also be updated either with DNS UPDATE
[RFC2136] or using a primary / secondary synchronization.
5.1. Securing the Synchronization Channel between HNA and DM
The Synchronization Channel used standard DNS request.
First the primary notifies the secondary that the zone must be
updated and eaves the secondary to proceed with the update when
possible/ convenient.
Then, a NOTIFY message is sent by the primary, which is a small
packet that is less likely to load the secondary.
Finally, the AXFR [RFC1034] or IXFR [RFC1995] query performed by the
secondary is a small packet sent over TCP (section 4.2 [RFC5936]),
which mitigates reflection attacks using a forged NOTIFY.
The AXFR request from the DM to the HNA SHOULD be secured. DNS over
TLS [RFC7858] is RECOMMENDED.
When using TLS, the HNA MAY authenticate inbound connections from the
DM using standard mechanisms, such as a public certificate with
baked-in root certificates on the HNA, or via DANE {!RFC6698}}
The HNA MAY apply a simple IP filter on inbound AXFR requests to
ensure they only arrive from the DM Synchronization Channel. In this
case, the HNA SHOULD regularly check (via DNS resolution) that the
address of the DM in the filter is still valid.
6. DM Distribution Channel
The DM Distribution Channel is used for communication between the DM
and the Public Authoritative Servers. The architecture and
communication used for the DM Distribution Channels is outside the
scope of this document, and there are many existing solutions
available e.g. rsynch, DNS AXFR, REST, DB copy.
7. HNA Security Policies
This section details security policies related to the Hidden Primary
/ Secondary synchronization.
The Hidden Primary, as described in this document SHOULD drop any
queries from the home network. This could be implemented via port
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binding and/or firewall rules. The precise mechanism deployed is out
of scope of this document. The Hidden Primary SHOULD drop any DNS
queries arriving on the WAN interface that are not issued from the
DM. The Hidden Primary SHOULD drop any outgoing packets other than
DNS NOTIFY query, SOA response, IXFR response or AXFR responses. The
Hidden Primary SHOULD drop any incoming packets other than DNS NOTIFY
response, SOA query, IXFR query or AXFR query. The Hidden Primary
SHOULD drop any non protected IXFR or AXFR exchange,depending on how
the synchronization is secured.
8. DNSSEC compliant Homenet Architecture
[RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on both
the authoritative server and the resolver. The resolver side is out
of scope of this document, and only the authoritative part of the
server is considered.
This document assumes the HNA signs the Public Homenet Zone.
Secure delegation is achieved only if the DS RRset is properly set in
the parent zone. Secure delegation is performed by the HNA or the
Outsourcing Infrastructures.
The DS RRset can be updated manually with nsupdate for example. This
requires the HNA or the Outsourcing Infrastructure to be
authenticated by the DNS server hosting the parent of the Public
Homenet Zone. Such a trust channel between the HNA and the parent
DNS server may be hard to maintain with HNAs, and thus may be easier
to establish with the Outsourcing Infrastructure. In fact, the
Public Authoritative Server(s) may use Automating DNSSEC Delegation
Trust Maintenance [RFC7344].
9. Homenet Reverse Zone
The Public Homenet Zone is associated to a Registered Homenet Domain
and the ownership of that domain requires a specific registration
from the end user as well as the HNA being provisioned with some
authentication credentials . Such steps are mandatory unless the
Outsourcing Infrastructure has some other means to authenticate the
HNA. Such situation may occur, for example, when the ISP provides
the Homenet Domain as well as the Outsourcing Infrastructure. In
this case, the HNA may be authenticated by the physical link layer,
in which case the authentication of the HNA may be performed without
additional provisioning of the HNA. While this may be not so common
for the Public Homenet Zone, this situation is expected to be quite
common for the Reverse Homenet Zone.
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More specifically, a common case is that the upstream ISP provides
the IPv6 prefix to the Homenet with a IA_PD [RFC8415] option and
manages the Outsourcing Infrastructure of the associated reverse
zone. This leave place for setting up automatically the relation
between HNA and the Outsourcing infrastructure as described in
[I-D.ietf-homenet-naming-architecture-dhc-options].
With this relation automatically configured, the synchronization
between the Home network and the Outsourcing infrastructure happens
similarly as for the Public Homenet Zone described earlier in this
document.
Note that for home networks hosted by multiple ISPs, each ISP
provides only the Outsourcing Infrastructure of the reverse zones
associated to the delegated prefix.
It is also likely that the DNS exchanges will need to be performed on
dedicated interfaces as to be accepted by the ISP. More
specifically, the reverse zone associated to prefix 1 will not be
possible to be performs by the HNA using an IP address that belongs
to prefix 2. Such constraints does not raise major concerns either
for hot standby or load sharing configuration.
With IPv6, the domain space for IP addresses is so large that reverse
zone may be confronted with scalability issues. How the reverse zone
is generated is out of scope of this document.
[I-D.howard-dnsop-ip6rdns] provides guidance on how to address
scalability issues.
10. Renumbering
This section details how renumbering is handled by the Hidden Primary
server or the DM. Both types of renumbering are discussed i.e.
"make-before-break" and "break-before-make".
In the make-before-break renumbering scenario, the new prefix is
advertised, the network is configured to prepare the transition to
the new prefix. During a period of time, the two prefixes old and
new coexist, before the old prefix is completely removed. In the
break-before-make renumbering scenario, the new prefix is advertised
making the old prefix obsolete.
Renumbering has been extensively described in [RFC4192] and analyzed
in [RFC7010] and the reader is expected to be familiar with them
before reading this section.
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10.1. Hidden Primary
In a renumbering scenario, the Hidden Primary is informed it is being
renumbered. In most cases, this occurs because the whole home
network is being renumbered. As a result, the Public Homenet Zone
will also be updated. Although the new and old IP addresses may be
stored in the Public Homenet Zone, we recommend that only the newly
reachable IP addresses be published.
To avoid reachability disruption, IP connectivity information
provided by the DNS SHOULD be coherent with the IP plane. In our
case, this means the old IP address SHOULD NOT be provided via the
DNS when it is not reachable anymore. Let for example TTL be the TTL
associated with a RRset of the Public Homenet Zone, it may be cached
for TTL seconds. Let T_NEW be the time the new IP address replaces
the old IP address in the Homenet Zone, and T_OLD_UNREACHABLE the
time the old IP is not reachable anymore.
In the case of the make-before-break, seamless reachability is
provided as long as T_OLD_UNREACHABLE - T_NEW > 2 * TTL. If this is
not satisfied, then devices associated with the old IP address in the
home network may become unreachable for 2 * TTL - (T_OLD_UNREACHABLE
- T_NEW). In the case of a break-before-make, T_OLD_UNREACHABLE =
T_NEW, and the device may become unreachable up to 2 * TTL.
Once the Public Homenet Zone file has been updated on the Hidden
Primary, the Hidden Primary needs to inform the Outsourcing
Infrastructure that the Public Homenet Zone has been updated and that
the IP address to use to retrieve the updated zone has also been
updated. Both notifications are performed using regular DNS
exchanges. Mechanisms to update an IP address provided by lower
layers with protocols like SCTP [RFC4960], MOBIKE [RFC4555] are not
considered in this document.
The Hidden Primary SHOULD inform the DM that the Public Homenet Zone
has been updated by sending a NOTIFY payload with the new IP address.
In addition, this NOTIFY payload SHOULD be authenticated using SIG(0)
or TSIG. When the DM receives the NOTIFY payload, it MUST
authenticate it. Note that the cryptographic key used for the
authentication SHOULD be indexed by the Registered Homenet Domain
contained in the NOTIFY payload as well as the RRSIG. In other
words, the IP address SHOULD NOT be used as an index. If
authentication succeeds, the DM MUST also notice the IP address has
been modified and perform a reachability check before updating its
primary configuration. The routability check MAY performed by
sending a SOA request to the Hidden Primary using the source IP
address of the NOTIFY. This exchange is also secured, and if an
authenticated response is received from the Hidden Primary with the
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new IP address, the DM SHOULD update its configuration file and
retrieve the Public Homenet Zone using an AXFR or a IXFR exchange.
Note that the primary reason for providing the IP address is that the
Hidden Primary is not publicly announced in the DNS. If the Hidden
Primary were publicly announced in the DNS, then the IP address
update could have been performed using the DNS as described in
Section 10.2.
10.2. Distribution Master
Renumbering of the Distribution Master results in it changing its IP
address. As the DM is a secondary, the destination of DNS NOTIFY
payloads MUST be changed, and any configuration/firewalling that
restricts DNS AXFR/IXFR operations MUST be updated.
If the DM is configured in the Hidden Primary configuration file
using a FQDN, then the update of the IP address is performed by DNS.
More specifically, before sending the NOTIFY, the Hidden Primary
performs a DNS resolution to retrieve the IP address of the
secondary.
As described in Section 10.1, the DM DNS information SHOULD be
coherent with the IP plane. The TTL of the Distribution Master name
SHOULD be adjusted appropriately prior to changing the IP address.
Some DNS infrastructure uses the IP address to designate the
secondary, in which case, other mechanisms must be found. The reason
for using IP addresses instead of names is generally to reach an
internal interface that is not designated by a FQDN, and to avoid
potential bootstrap problems. Such scenarios are considered as out
of scope in the case of home networks.
11. Operational considerations for Offline/Disconnected resolution
This section is non-normative. It provides suggestions on
operational consideration. TBD.
12. Privacy Considerations
Outsourcing the DNS Authoritative service from the HNA to a third
party raises a few privacy related concerns.
The Public Homenet Zone contains a full description of the services
hosted in the network. These services may not be expected to be
publicly shared although their names remain accessible through the
Internet. Even though DNS makes information public, the DNS does not
expect to make the complete list of services public. In fact, making
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information public still requires the key (or FQDN) of each service
to be known by the resolver in order to retrieve information about
the services. More specifically, making mywebsite.example.com public
in the DNS, is not sufficient to make resolvers aware of the
existence web site. However, an attacker may walk the reverse DNS
zone, or use other reconnaissance techniques to learn this
information as described in [RFC7707].
In order to prevent the complete Public Homenet Zone being published
on the Internet, AXFR queries SHOULD be blocked on the Public
Authoritative Server(s). Similarly, to avoid zone-walking NSEC3
[RFC5155] SHOULD be preferred over NSEC [RFC4034]. When the Public
Homenet Zone is outsourced, the end user should be aware that it
provides a complete description of the services available on the home
network. More specifically, names usually provides a clear
indication of the service and possibly even the device type, and as
the Public Homenet Zone contains the IP addresses associated with the
service, they also limit the scope of the scan space.
In addition to the Public Homenet Zone, the third party can also
monitor the traffic associated with the Public Homenet Zone. This
traffic may provide an indication of the services an end user
accesses, plus how and when they use these services. Although,
caching may obfuscate this information inside the home network, it is
likely that outside your home network this information will not be
cached.
13. Security Considerations
The Homenet Naming Architecture described in this document solves
exposing the HNA's DNS service as a DoS attack vector.
13.1. HNA DM channels
The HNA DM channels are specified to include their own security
mechanisms that are designed to provide the minimum attacke surface,
and to authenticate transactions where necessary.
Note that in the case of the Reverse Homenet Zone, the data is less
subject to attacks than in the Public Homenet Zone. In addition, the
HNA and the DM MAY belong to the same administrative domain, i.e. the
ISP. More specifically, the WAN interface is located in the ISP
network. As a result, if provisioned using DHCPv6, the security
credential may not even transit in the home network. On the other
hand, if the HNA is not hosted at the border of the home network, the
credential may rely on the security associated to DHCPv6. Even if
HNA and DM are in the same administrative domain it is strongly
RECOMMENDED to use a secure channel.
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13.2. Names are less secure than IP addresses
This document describes how an end user can make their services and
devices from his home network reachable on the Internet by using
names rather than IP addresses. This exposes the home network to
attackers, since names are expected to include less entropy than IP
addresses. In fact, with IP addresses, the Interface Identifier is
64 bits long leading to up to 2^64 possibilities for a given
subnetwork. This is not to mention that the subnet prefix is also of
64 bits long, thus providing up to 2^64 possibilities. On the other
hand, names used either for the home network domain or for the
devices present less entropy (livebox, router, printer, nicolas,
jennifer, ...) and thus potentially exposes the devices to dictionary
attacks.
13.3. Names are less volatile than IP addresses
IP addresses may be used to locate a device, a host or a service.
However, home networks are not expected to be assigned a time
invariant prefix by ISPs. As a result, observing IP addresses only
provides some ephemeral information about who is accessing the
service. On the other hand, names are not expected to be as volatile
as IP addresses. As a result, logging names over time may be more
valuable than logging IP addresses, especially to profile an end
user's characteristics.
PTR provides a way to bind an IP address to a name. In that sense,
responding to PTR DNS queries may affect the end user's privacy. For
that reason end users may choose not to respond to PTR DNS queries
and MAY instead return a NXDOMAIN response.
13.4. DNS Reflection Attacks
An attacker performs a reflection attack when it sends traffic to one
or more intermediary nodes (reflectors), that in turn send back
response traffic to the victim. Motivations for using an
intermediary node might be anonymity of the attacker, as well as
amplification of the traffic. Typically, when the intermediary node
is a DNSSEC server, the attacker sends a DNSSEC query and the victim
is likely to receive a DNSSEC response. This section analyzes how
the different components may be involved as a reflector in a
reflection attack. Section 13.5 considers the Hidden Primary,
Section 13.6 the Synchronization Server, and Section 13.7 the Public
Authoritative Server(s).
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13.5. Reflection Attack involving the Hidden Primary
With the specified architecture, the Hidden Primary is only expected
to receive DNS queries of type SOA, AXFR or IXFR. This section
analyzes how these DNS queries may be used by an attacker to perform
a reflection attack.
DNS queries of type AXFR and IXFR use TCP and as such are less
subject to reflection attacks. This makes SOA queries the only
remaining practical vector of attacks for reflection attacks, based
on UDP.
SOA queries are not associated with a large amplification factor
compared to queries of type "ANY" or to query of non existing FQDNs.
This reduces the probability a DNS query of type SOA will be involved
in a DDoS attack.
SOA queries are expected to follow a very specific pattern, which
makes rate limiting techniques an efficient way to limit such
attacks, and associated impact on the naming service of the home
network.
Motivations for such a flood might be a reflection attack, but could
also be a resource exhaustion attack performed against the Hidden
Primary. The Hidden Primary only expects to exchange traffic with
the DM, that is its associated secondary. Even though secondary
servers may be renumbered as mentioned in Section 10, the Hidden
Primary is likely to perform a DNSSEC resolution and find out the
associated secondary's IP addresses in use. As a result, the Hidden
Primary is likely to limit the origin of its incoming traffic based
on the origin IP address.
With filtering rules based on IP address, SOA flooding attacks are
limited to forged packets with the IP address of the secondary
server. In other words, the only victims are the Hidden Primary
itself or the secondary. There is a need for the Hidden Primary to
limit that flood to limit the impact of the reflection attack on the
secondary, and to limit the resource needed to carry on the traffic
by the HNA hosting the Hidden Primary. On the other hand, mitigation
should be performed appropriately, so as to limit the impact on the
legitimate SOA sent by the secondary.
The main reason for the DM sending a SOA query is to update the SOA
RRset after the TTL expires, to check the serial number upon the
receipt of a NOTIFY query from the Hidden Primary, or to re-send the
SOA request when the response has not been received. When a flood of
SOA queries is received by the Hidden Primary, the Hidden Primary may
assume it is involved in an attack.
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There are few legitimate time slots when the secondary is expected to
send a SOA query. Suppose T_NOTIFY is the time a NOTIFY is sent by
the Hidden Primary, T_SOA the last time the SOA has been queried, TTL
the TTL associated to the SOA, and T_REFRESH the refresh time defined
in the SOA RRset. The specific time SOA queries are expected can be
for example T_NOTIFY, T_SOA + 2/3 TTL, T_SOA + TTL, T_SOA +
T_REFRESH., and. Outside a few minutes following these specific time
slots, the probability that the HNA discards a legitimate SOA query
is very low. Within these time slots, the probability the secondary
may have its legitimate query rejected is higher. If a legitimate
SOA is discarded, the secondary will re-send SOA query every "retry
time" second until "expire time" seconds occurs, where "retry time"
and "expire time" have been defined in the SOA.
As a result, it is RECOMMENDED to set rate limiting policies to
protect HNA resources. If a flood lasts more than the expired time
defined by the SOA, it is RECOMMENDED to re-initiate a
synchronization between the Hidden Primary and the secondaries.
13.6. Reflection Attacks involving the DM
The DM acts as a secondary coupled with the Hidden Primary. The
secondary expects to receive NOTIFY query, SOA responses, AXFR and
IXFR responses from the Hidden Primary.
Sending a NOTIFY query to the secondary generates a NOTIFY response
as well as initiating an SOA query exchange from the secondary to the
Hidden Primary. As mentioned in [RFC1996], this is a known "benign
denial of service attack". As a result, the DM SHOULD enforce rate
limiting on sending SOA queries and NOTIFY responses to the Hidden
Primary. Most likely, when the secondary is flooded with valid and
signed NOTIFY queries, it is under a replay attack which is discussed
in Section 13.9. The key thing here is that the secondary is likely
to be designed to be able to process much more traffic than the
Hidden Primary hosted on a HNA.
This paragraph details how the secondary may limit the NOTIFY
queries. Because the Hidden Primary may be renumbered, the secondary
SHOULD NOT perform permanent IP filtering based on IP addresses. In
addition, a given secondary may be shared among multiple Hidden
Primaries which make filtering rules based on IP harder to set. The
time at which a NOTIFY is sent by the Hidden Primary is not
predictable. However, a flood of NOTIFY messages may be easily
detected, as a NOTIFY originated from a given Homenet Zone is
expected to have a very limited number of unique source IP addresses,
even when renumbering is occurring. As a result, the secondary, MAY
rate limit incoming NOTIFY queries.
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On the Hidden Primary side, it is recommended that the Hidden Primary
sends a NOTIFY as long as the zone has not been updated by the
secondary. Multiple SOA queries may indicate the secondary is under
attack.
13.7. Reflection Attacks involving the Public Authoritative Servers
Reflection attacks involving the Public Authoritative Server(s) are
similar to attacks on any Outsourcing Infrastructure. This is not
specific to the architecture described in this document, and thus are
considered as out of scope.
In fact, one motivation of the architecture described in this
document is to expose the Public Authoritative Server(s) to attacks
instead of the HNA, as it is believed that the Public Authoritative
Server(s) will be better able to defend itself.
13.8. Flooding Attack
The purpose of flooding attacks is mostly resource exhaustion, where
the resource can be bandwidth, memory, or CPU for example.
One goal of the architecture described in this document is to limit
the surface of attack on the HNA. This is done by outsourcing the
DNS service to the Public Authoritative Server(s). By doing so, the
HNA limits its DNS interactions between the Hidden Primary and the
DM. This limits the number of entities the HNA interacts with as
well as the scope of DNS exchanges - NOTIFY, SOA, AXFR, IXFR.
The use of an authenticated channel with SIG(0) or TSIG between the
HNA and the DM, enables detection of illegitimate DNS queries, so
appropriate action may be taken - like dropping the queries. If
signatures are validated, then most likely, the HNA is under a replay
attack, as detailed in Section 13.9
In order to limit the resource required for authentication, it is
recommended to use TSIG that uses symmetric cryptography over SIG(0)
that uses asymmetric cryptography.
13.9. Replay Attack
Replay attacks consist of an attacker either resending or delaying a
legitimate message that has been sent by an authorized user or
process. As the Hidden Primary and the DM use an authenticated
channel, replay attacks are mostly expected to use forged DNS queries
in order to provide valid traffic.
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From the perspective of an attacker, using a correctly authenticated
DNS query may not be detected as an attack and thus may generate a
response. Generating and sending a response consumes more resources
than either dropping the query by the defender, or generating the
query by the attacker, and thus could be used for resource exhaustion
attacks. In addition, as the authentication is performed at the DNS
layer, the source IP address could be impersonated in order to
perform a reflection attack.
Section 13.4 details how to mitigate reflection attacks and
Section 13.8 details how to mitigate resource exhaustion. Both
sections assume a context of DoS with a flood of DNS queries. This
section suggests a way to limit the attack surface of replay attacks.
As SIG(0) and TSIG use inception and expiration time, the time frame
for replay attack is limited. SIG(0) and TSIG recommends a fudge
value of 5 minutes. This value has been set as a compromise between
possibly loose time synchronization between devices and the valid
lifetime of the message. As a result, better time synchronization
policies could reduce the time window of the attack.
[](<!- <section title="DNSSEC is recommended to authenticate DNS
hosted data
Deploying DNSSEC is recommended, since in some cases the information
stored in the DNS is used by the ISP or an IT department to grant
access. For example some servers may perform PTR DNS queries to
grant access based on host names. DNSSEC mitigates lack of trust in
DNS, and it is RECOMMENDED to deploy DNSSEC on HNAs.
->)
14. IANA Considerations
This document has no actions for IANA.
15. Acknowledgment
The authors wish to thank Philippe Lemordant for its contributions on
the early versions of the draft; Ole Troan for pointing out issues
with the IPv6 routed home concept and placing the scope of this
document in a wider picture; Mark Townsley for encouragement and
injecting a healthy debate on the merits of the idea; Ulrik de Bie
for providing alternative solutions; Paul Mockapetris, Christian
Jacquenet, Francis Dupont and Ludovic Eschard for their remarks on
HNA and low power devices; Olafur Gudmundsson for clarifying DNSSEC
capabilities of small devices; Simon Kelley for its feedback as
dnsmasq implementer; Andrew Sullivan, Mark Andrew, Ted Lemon, Mikael
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Abrahamson, Michael Richardson and Ray Bellis for their feedback on
handling different views as well as clarifying the impact of
outsourcing the zone signing operation outside the HNA; Mark Andrew
and Peter Koch for clarifying the renumbering.
16. Annex
16.1. Envisioned deployment scenarios
A number of deployment have been envisionned, this section aims at
providing a brief description. The use cases are not limitatives and
this section is not normative.
16.1.1. CPE Vendor
A specific vendor with specific relations with a registrar or a
registry may sell a CPE that is provisioned with provisioned domain
name. Such domain name does not need to be necessary human readable.
One possible way is that the vendor also provisions the HNA with a
private and public keys as well as a certificate. Note that these
keys are not expected to be used for DNSSEC signing. Instead these
keys are solely used by the HNA to proceed to the authentication.
Normally the keys should be necessary and sufficient to proceed to
the authentication. The reason to combine the domain name and the
key is that outsourcing infrastructure are likely handle names better
than keys and that domain names might be used as a login which
enables the key to be regenerated.
When the home network owner plugs the CPE at home, the relation
between HNA and DM is expected to work out-of-the-box.
16.1.2. Agnostic CPE
An CPE that is not preconfigured may also take advanatge to the
protocol defined in this document but some configuration steps will
be needed.
1. The owner of the home network buys a domain name to a registrar,
and as such creates an account on that registrar
2. Either the registrar is also providing the outsourcing
infrastructure or the home network needs to create a specific
account on the outsourcing infrastructure. * If the outsourcing
provider is the registrar, the outsourcing has by design a proof
of ownership of the domain name by the homenet owner. In this
case, it is expected the infrastructure provides the necessary
parameters to the home network owner to configure the HNA. A
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good way to provide the parameters would be the home network be
able to copy/paste a JSON object. What matters at that point is
the outsourcing infrastructure being able to generate
authentication credentials for the HNA to authenticate itself to
the outsourcing infrastructure. This obviously requires the home
network to provide the public key gnerated by the HNA in a CSR.
o If the outsourcing infrastructure is not the registrar, then the
proof of ownership needs to be established using protocols like
ACME for example that will end in the generation of a certificate.
ACME is used here to the purpose of automating the generation of
the certificate, the CA may be a specific CA or the outsourcing
infrastructure. With that being done, the outsourcing
infrastructure has a roof of ownership and can proceed as above.
16.2. Example: Homenet Zone
This section is not normative and intends to illustrate how the HNA
builds the Homenet Zone.
As depicted in Figure 1, the Public Homenet Zone is hosted on the
Public Authoritative Server(s), whereas the Homenet Zone is hosted on
the HNA. This section considers that the HNA builds the zone that
will be effectively published on the Public Authoritative Server(s).
In other words "Homenet to Public Zone transformation" is the
identity also commonly designated as "no operation" (NOP).
In that case, the Homenet Zone should configure its Name Server RRset
(NS) and Start of Authority (SOA) with the values associated with the
Public Authoritative Server(s). This is illustrated in Figure 2.
public.primary.example.net is the FQDN of the Public Authoritative
Server(s), and IP1, IP2, IP3, IP4 are the associated IP addresses.
Then the HNA should add the additional new nodes that enter the home
network, remove those that should be removed, and sign the Homenet
Zone.
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$ORIGIN example.com
$TTL 1h
@ IN SOA public.primary.example.net
hostmaster.example.com. (
2013120710 ; serial number of this zone file
1d ; secondary refresh
2h ; secondary retry time in case of a problem
4w ; secondary expiration time
1h ; maximum caching time in case of failed
; lookups
)
@ NS public.authoritative.servers.example.net
public.primary.example.net A @IP1
public.primary.example.net A @IP2
public.primary.example.net AAAA @IP3
public.primary.example.net AAAA @IP4
Figure 2: Homenet Zone
The SOA RRset is defined in [RFC1033], [RFC1035] and [RFC2308]. This
SOA is specific, as it is used for the synchronization between the
Hidden Primary and the DM and published on the DNS Public
Authoritative Server(s)..
o MNAME: indicates the primary. In our case the zone is published
on the Public Authoritative Server(s), and its name MUST be
included. If multiple Public Authoritative Server(s) are
involved, one of them MUST be chosen. More specifically, the HNA
MUST NOT include the name of the Hidden Primary.
o RNAME: indicates the email address to reach the administrator.
[RFC2142] recommends using hostmaster@domain and replacing the '@'
sign by '.'.
o REFRESH and RETRY: indicate respectively in seconds how often
secondaries need to check the primary, and the time between two
refresh when a refresh has failed. Default values indicated by
[RFC1033] are 3600 (1 hour) for refresh and 600 (10 minutes) for
retry. This value might be too long for highly dynamic content.
However, the Public Authoritative Server(s) and the HNA are
expected to implement NOTIFY [RFC1996]. So whilst shorter refresh
timers might increase the bandwidth usage for secondaries hosting
large number of zones, it will have little practical impact on the
elapsed time required to achieve synchronization between the
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Outsourcing Infrastructure and the Hidden Master. As a result,
the default values are acceptable.
o EXPIRE: is the upper limit data SHOULD be kept in absence of
refresh. The default value indicated by [RFC1033] is 3600000
(approx. 42 days). In home network architectures, the HNA
provides both the DNS synchronization and the access to the home
network. This device may be plugged and unplugged by the end user
without notification, thus we recommend a long expiry timer.
o MINIMUM: indicates the minimum TTL. The default value indicated
by [RFC1033] is 86400 (1 day). For home network, this value MAY
be reduced, and 3600 (1 hour) seems more appropriate.
<<!-- ## Considerations on multiple Registered Homenet Domain Names
## are left for future versions When multiple Registered Homenet
Domains are used -like example.com, example.net, example.org, a DNS
Homenet Zone file per Registered Homenet Domain SHOULD be generated.
In order to synchronize the zone contents, the HNA may provide all
bindings in each zone files. As a result, any update MUST be
performed on all zone files, i.e. for all Registered Homenet Domains.
To limit thees updates when multiple Registered Homenet Domains are
involved, the HNA MAY fill all bindings in a specific zone file and
redirect all other zones to that zone. This can be achieved with
redirecting mechanisms like CNAME {{RFC2181}}, {{RFC1034}}, DNAME
{{RFC6672}} or CNAME+DNAME {{I-D.sury-dnsext-cname-dname}}. This is
an implementation issue to determine whether redirection mechanisms
MAY be preferred for large Homenet Zones, or when the number of
Registered Homenet Domain becomes quite large. -->>
16.3. Example: HNA necessary parameters for outsourcing
This section specifies the various parameters required by the HNA to
configure the naming architecture of this document. This section is
informational, and is intended to clarify the information handled by
the HNA and the various settings to be done.
DM may be configured with the following parameters. These parameters
are necessary to establish a secure channel between the HNA and the
DM as well as to specify the DNS zone that is in the scope of the
communication:
o DM: The associated FQDNs or IP addresses of the DM. IP addresses
are optional and the FQDN is sufficient. To secure the binding
name and IP addresses, a DNSSEC exchange is required. Otherwise,
the IP addresses should be entered manually.
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o Authentication Method: How the HNA authenticates itself to the DM.
This MAY depend on the implementation but this should cover at
least IPsec, DTLS and TSIG
o Authentication data: Associated Data. PSK only requires a single
argument. If other authentication mechanisms based on
certificates are used, then HNA private keys, certificates and
certification authority should be specified.
o Public Authoritative Server(s): The FQDN or IP addresses of the
Public Authoritative Server(s). It MAY correspond to the data
that will be set in the NS RRsets and SOA of the Homenet Zone. IP
addresses are optional and the FQDN is sufficient. To secure the
binding between name and IP addresses, a DNSSEC exchange is
required. Otherwise, the IP addresses should be entered manually.
o Registered Homenet Domain: The domain name used to establish the
secure channel. This name is used by the DM and the HNA for the
primary / secondary configuration as well as to index the NOTIFY
queries of the HNA when the HNA has been renumbered.
Setting the Homenet Zone requires the following information.
o Registered Homenet Domain: The Domain Name of the zone. Multiple
Registered Homenet Domains may be provided. This will generate
the creation of multiple Public Homenet Zones.
o Public Authoritative Server(s): The Public Authoritative Server(s)
associated with the Registered Homenet Domain. Multiple Public
Authoritative Server(s) may be provided.
Two possible methods of providing the required information would be:
JSON for forward zones should be standardized in a similar way to
zone file layout in RFC1035
DHCP for reverse zones needs a separate draft
17. References
17.1. Normative References
[RFC1033] Lottor, M., "Domain Administrators Operations Guide",
RFC 1033, DOI 10.17487/RFC1033, November 1987,
<https://www.rfc-editor.org/info/rfc1033>.
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[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>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, DOI 10.17487/RFC2136, April 1997,
<https://www.rfc-editor.org/info/rfc2136>.
[RFC2142] Crocker, D., "Mailbox Names for Common Services, Roles and
Functions", RFC 2142, DOI 10.17487/RFC2142, May 1997,
<https://www.rfc-editor.org/info/rfc2142>.
[RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS
Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997,
<https://www.rfc-editor.org/info/rfc2181>.
[RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS
NCACHE)", RFC 2308, DOI 10.17487/RFC2308, March 1998,
<https://www.rfc-editor.org/info/rfc2308>.
[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>.
[RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures
( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September
2000, <https://www.rfc-editor.org/info/rfc2931>.
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[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, DOI 10.17487/RFC4034, March 2005,
<https://www.rfc-editor.org/info/rfc4034>.
[RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for
Renumbering an IPv6 Network without a Flag Day", RFC 4192,
DOI 10.17487/RFC4192, September 2005,
<https://www.rfc-editor.org/info/rfc4192>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, DOI 10.17487/RFC4555, June 2006,
<https://www.rfc-editor.org/info/rfc4555>.
[RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol",
RFC 4960, DOI 10.17487/RFC4960, September 2007,
<https://www.rfc-editor.org/info/rfc4960>.
[RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
Security (DNSSEC) Hashed Authenticated Denial of
Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008,
<https://www.rfc-editor.org/info/rfc5155>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[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>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC6644] Evans, D., Droms, R., and S. Jiang, "Rebind Capability in
DHCPv6 Reconfigure Messages", RFC 6644,
DOI 10.17487/RFC6644, July 2012,
<https://www.rfc-editor.org/info/rfc6644>.
[RFC6672] Rose, S. and W. Wijngaards, "DNAME Redirection in the
DNS", RFC 6672, DOI 10.17487/RFC6672, June 2012,
<https://www.rfc-editor.org/info/rfc6672>.
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[RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762,
DOI 10.17487/RFC6762, February 2013,
<https://www.rfc-editor.org/info/rfc6762>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>.
[RFC7010] Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W.
George, "IPv6 Site Renumbering Gap Analysis", RFC 7010,
DOI 10.17487/RFC7010, September 2013,
<https://www.rfc-editor.org/info/rfc7010>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating
DNSSEC Delegation Trust Maintenance", RFC 7344,
DOI 10.17487/RFC7344, September 2014,
<https://www.rfc-editor.org/info/rfc7344>.
[RFC7368] Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J.
Weil, "IPv6 Home Networking Architecture Principles",
RFC 7368, DOI 10.17487/RFC7368, October 2014,
<https://www.rfc-editor.org/info/rfc7368>.
[RFC7558] Lynn, K., Cheshire, S., Blanchet, M., and D. Migault,
"Requirements for Scalable DNS-Based Service Discovery
(DNS-SD) / Multicast DNS (mDNS) Extensions", RFC 7558,
DOI 10.17487/RFC7558, July 2015,
<https://www.rfc-editor.org/info/rfc7558>.
[RFC7707] Gont, F. and T. Chown, "Network Reconnaissance in IPv6
Networks", RFC 7707, DOI 10.17487/RFC7707, March 2016,
<https://www.rfc-editor.org/info/rfc7707>.
[RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking
Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April
2016, <https://www.rfc-editor.org/info/rfc7788>.
[RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
and P. Hoffman, "Specification for DNS over Transport
Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
2016, <https://www.rfc-editor.org/info/rfc7858>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8375] Pfister, P. and T. Lemon, "Special-Use Domain
'home.arpa.'", RFC 8375, DOI 10.17487/RFC8375, May 2018,
<https://www.rfc-editor.org/info/rfc8375>.
[RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A.,
Richardson, M., Jiang, S., Lemon, T., and T. Winters,
"Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 8415, DOI 10.17487/RFC8415, November 2018,
<https://www.rfc-editor.org/info/rfc8415>.
17.2. Informative References
[I-D.howard-dnsop-ip6rdns]
Howard, L., "Reverse DNS in IPv6 for Internet Service
Providers", draft-howard-dnsop-ip6rdns-00 (work in
progress), June 2014.
[I-D.ietf-homenet-naming-architecture-dhc-options]
Migault, D., Mrugalski, T., Griffiths, C., Weber, R., and
W. Cloetens, "DHCPv6 Options for Homenet Naming
Architecture", draft-ietf-homenet-naming-architecture-dhc-
options-06 (work in progress), June 2018.
[I-D.ietf-homenet-simple-naming]
Lemon, T., Migault, D., and S. Cheshire, "Homenet Naming
and Service Discovery Architecture", draft-ietf-homenet-
simple-naming-03 (work in progress), October 2018.
[I-D.sury-dnsext-cname-dname]
Sury, O., "CNAME+DNAME Name Redirection", draft-sury-
dnsext-cname-dname-00 (work in progress), April 2010.
Authors' Addresses
Daniel Migault
Ericsson
8275 Trans Canada Route
Saint Laurent, QC 4S 0B6
Canada
EMail: daniel.migault@ericsson.com
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Ralf Weber
Nominum
2000 Seaport Blvd
Redwood City 94063
US
EMail: ralf.weber@nominum.com
Michael Richardson
Sandelman Software Works
470 Dawson Avenue
Ottawa, ON K1Z 5V7
Canada
EMail: mcr+ietf@sandelman.ca
Ray Hunter
Globis Consulting BV
Weegschaalstraat 3
Eindhoven 5632CW
NL
EMail: v6ops@globis.net
Chris Griffiths
EMail: cgriffiths@gmail.com
Wouter Cloetens
SoftAtHome
vaartdijk 3 701
Wijgmaal 3018
BE
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Migault, et al. Expires September 10, 2020 [Page 38]