Internet-Draft public-names September 2022
Migault, et al. Expires 24 March 2023 [Page]
Intended Status:
Standards Track
D. Migault
R. Weber
M. Richardson
Sandelman Software Works
R. Hunter
Globis Consulting BV

Simple Provisioning of Public Names for Residential Networks


Home network owners often have devices and services that they wish to access outside their home network - i.e., from the Internet using their names. To do so, these names need to be made publicly available in the DNS.

This document describes how a Homenet Naming Authority (HNA) can instruct a DNS Outsourcing Infrastructure (DOI) to publish a Public Homenet Zone on its behalf.

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

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 24 March 2023.

Table of Contents

1. Introduction

Home network owners often have devices and services that they wish to access outside their home network - i.e., from the Internet using their names. To do so, these names needs to be made publicly available in the DNS.

This document describes how a Homenet Naming Authority (HNA) can instruct a DNS Outsourcing Infrastructure (DOI) to publish a Public Homenet Zone on its behalf.

The document introduces the Synchronization Channel and the Control Channel between the HNA and the Distribution Manager (DM) that belongs to the DOI.

The Synchronization Channel (see Section 5) is used to synchronize the Public Homenet Zone. The HNA is configured as a primary, while the DM is configured as a secondary.

The Control Channel (see Section 4) is used to set the Synchronization Channel. For example, to build the Public Homenet Zone, the HNA needs the authoritative servers (and associated IP addresses) of the servers of the DOI actually serving the zone. Similarly, the DOI needs to know the IP address of the primary (HNA) as well as potentially the hash of the KSK (DS RRset) to secure the DNSSEC delegation with the parent zone.

The remaining of the document is as follows. Section 3 provides an architectural view of the HNA, DM and DOI as well as its different communication channels (Control Channel, Synchronization Channel, DM Distribution Channel) respectively described in Section 4, Section 5 and Section 6. Section 7 and Section 9 respectively details HNA security policies as well as DNSSEC compliance within the home network. Section 10 discusses how renumbering should be handled. Finally, Section 11 and Section 12 respectively discuss privacy and security considerations when outsourcing the Public Homenet Zone.

The appendices discuss several management (see Section 8) provisioning (see Section 8), configurations (see Appendix B) and deployment (see Section 1.3 and Appendix C) aspects.

1.1. Selecting Names to Publish

While this document does not create any normative mechanism to select the names to publish, this document anticipates that the home network administrator (a human being), will be presented with a list of current names and addresses.

The administrator would mark which devices and services (by name), are to be published. The HNA would then collect the IPv6 address(es) associated with that device or service, and put the name into the Public Homenet Zone. The address of the device or service can be collected from a number of places: mDNS [RFC6762], DHCP [RFC8415], UPnP, PCP [RFC6887], or manual configuration.

A device or service may have Global Unicast Addresses (GUA) (IPv6 [RFC3787] or IPv4), Unique Local IPv6 Addresses (ULA) [RFC4193], as well IPv6-Link-Local addresses[RFC4291][RFC7404], IPv4-Link-Local Addresses [RFC3927] (LLA), and private IPv4 addresses [RFC1918]. Of these the link-local are never useful for the Public Zone, and should be omitted. The IPv6 ULA and the private IPv4 addresses may be useful to publish, if the home network environment features a VPN that would allow the home owner to reach the network.

The IPv6 ULA addresses are safer to publish with a significantly lower probability of collision than RFC1918 addresses.

In general, one expects the GUA to be the default address to be published. However, publishing the ULA and private IPv4 addresses may enable local communications within the home network. A direct advantage of enabling local communication is to enable communications even in case of Internet disruption. However, since communications are established with names which remains a global identifier, the communication can be protected by TLS the same way it is protected on the global Internet.

1.2. Dynamic DNS Alternative solutions

An alternative existing solution 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" [DDNS], and there are a number of commercial providers. While the IETF has defined Dynamic Update [RFC3007], in many - as far as the co-authors know in all cases - case commercial "Dynamic Update" solutions are implemented via a HTTPS RESTful API.

These solutions were typically used by a host behind the CPE and since the CPE implements some NAT, the host can only be reached from the global Internet via its CPE IPv4 address. This is the most common scenario considered in this section, while some variant may also consider the client being hosted in the CPE.

For a very few numbers of hosts, the use of such a system provides an alternative to the architecture described in this document. Dynamic DNS - even adapted to IPv6 and ignoring those associated to an IPv4 development - does suffer from some severe limitations:

  • the CPE/HNA router is unaware of the process, and cannot respond to queries for these names and communications to these names require an Internet connectivity is order to perform the DNS resolution. Such dependence does not meet the requirement for internal communications to be resilient to ISP connectivity disruptions [RFC7368].
  • 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.
  • 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.
  • "all the good names are taken" - current services provide a small set of zones shared by all hosts across all home networks. More especially, there is no notion of a domain specific home network. As there are some commonalities provided by individual home networks, there are often conflicts. This makes the home user or application dependent on having to resolve different names in the event of outages or disruptions. Distinguishing similar names by delegation of zones was among the primary design goals of the DNS system.
  • 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.
  • Dynamic Updates solution are not interoperable and each provider has its own way to implement it. [RFC3007] is the standard solution to update a DNS RRset, but most Dynamic Update providers use HTTPS RESTful API.

There is no technical reason why a RESTful service could not provide solutions to many of these problems, but this document describes a DNS-based solution.

1.3. Envisioned deployment scenarios

A number of deployment have been envisioned, this section aims at providing a brief description. The use cases are not limitations and this section is not normative.

1.3.1. 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 DOI 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.

1.3.2. Agnostic CPE

An CPE that is not preconfigured may also take advantage 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 DOI is the registrar, it has by design a proof of ownership of the domain name by the homenet owner. In this case, it is expected the DOI provides the necessary parameters to the home network owner to configure the HNA. A good way to provide the parameters would be the home network be able to copy/paste a JSON object - see Appendix B. What matters at that point is the DOI being able to generate authentication credentials for the HNA to authenticate itself to the DOI. This obviously requires the home network to provide the public key generated by the HNA in a CSR.
  • If the DOI is not the registrar, then the proof of ownership needs to be established using protocols like ACME [RFC8555] 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 DOI. With that being done, the DOI has a roof of ownership and can proceed as above.

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.

Customer Premises Equipment:
(CPE) is a router providing connectivity to the home network.
Homenet Zone:
is the DNS zone for use within the boundaries of the home network: '' (see [RFC8375]). This zone is not considered public and is out of scope for this document.
Registered Homenet Domain:
is the domain name that is associated with the home network.
Public Homenet Zone:
contains the names in the home network that are expected to be publicly resolvable on the Internet. A home network can have multiple Public Homenet Zones.

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 DNS Outsourcing Infrastructure (DOI).

DNS Outsourcing Infrastructure (DOI):
is the infrastructure responsible for receiving the Public Homenet Zone and publishing it on the Internet. It is mainly composed of a Distribution Manager and Public Authoritative Servers.
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.
Homenet Authoritative Servers:
are authoritative name servers for the Homenet Zone within the Homenet network.
Distribution Manager (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.
Homenet Reverse Zone:
The reverse zone file associated with the Public Homenet Zone.
Reverse Public Authoritative Servers:
equivalent to Public Authoritative Servers specifically for reverse resolution.
Reverse Distribution Manager:
equivalent to Distribution Manager specifically for reverse resolution.
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.
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.

3. Architecture Description

This section provides an overview of the architecture for outsourcing the authoritative naming service from the HNA to the DOI. Note that Appendix B defines necessary parameter to configure the HNA.

3.1. Architecture Overview

       Home network                 |         Internet
                                    | +----------------------------+
                                    | |          DOI               |
                          Control   | |                            |
+-----------------------+ Channel   | |  +-----------------------+ |
|         HNA           |<-------------->| Distribution Manager  | |
|+---------------------+|           | |  |+---------------------+| |
|| Public Homenet Zone ||Synchronization || Public Homenet Zone || |
||   (myhome.example)  || Channel   | |  ||  (myhome.example)   || |
|+---------------------+|<-------------->|+---------------------+| |
+-----------^-----------+           | |  +-----------------------+ |
            .                       | |           ^ Distribution   |
            .                       | |           | Channel        |
+-----------v-----------+           | |           v                |
| Homenet Authoritative |           | |  +-----------------------+ |
| Server(s)             |           | |  | Public Authoritative  | |
|+---------------------+|           | |  | Server(s)             | |
||Public Homenet Zone  ||           | |  |+---------------------+| |
||  (myhome.example)   ||           | |  || Public Homenet Zone || |
|+---------------------+|           | |  ||  (myhome.example)   || |
||     Homenet Zone    ||           | |  |+---------------------+| |
||     (     ||           | |  +-----------------------+ |
|+---------------------+|           | +----------^---|-------------+
+----------^---|--------+           |            |   |
           |   |           name resolution       |   |
           |   v                    |            |   v
 +----------------------+           | +-----------------------+
 |       Homenet        |           | |       Internet        |
 |    DNSSEC Resolver   |           | |    DNSSEC Resolver    |
 +----------------------+           | +-----------------------+
Figure 1: Homenet Naming Architecture

Figure 1 illustrates the architecture where the HNA outsources the publication of the Public Homenet Zone to the DOI. The DOI will serve every DNSSEC request of the Public Homenet Zone coming from outside the home network. When the request is coming within the home network, the resolution is expected to be handled by the Homenet Resolver as detaille din further details below.

The Public Homenet Zone is identified by the Registered Homenet Domain Name - myhome.example. The ".local" as well as "" are explicitly not considered as Public Homenet zones and represented as Homenet Zone in Figure 1.

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. 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 communicates and synchronizes it with the DOI using a primary/secondary setting as described in Figure 1. The HNA acts as a hidden primary [RFC8499] while the DM behaves as a secondary responsible to distribute the Public Homenet Zone to the multiple Public Authoritative Servers that DOI is responsible for. The DM has three communication channels:

  • DM Control Channel (Section 4) to configure the HNA and the DOI. This includes necessary parameters to configure the primary/secondary relation as well as some information provided by the DOI that needs to be included by the HNA in the Public Homenet Zone.
  • DM Synchronization Channel (Section 5) to synchronize the Public Homenet Zone on the HNA and on the DM with the appropriately configured primary/secondary.
  • one or more Distribution Channels (Section 6 that distribute the Public Homenet Zone from the DM to the Public Authoritative Server serving the Public Homenet Zone on the Internet.

There might be multiple DM's, and multiple servers per DM. This document assumes a single DM server for simplicity, but there is no reason why each channel needs to be implemented on the same server or 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. More specifically, 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 DOI 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 (myhome.example) 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 WAN connectivity disruption, the Homenet DNSSEC Resolver SHOULD be able to perform the resolution on 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 [RFC7788] or a by configuring a trust anchor [I-D.ietf-dnsop-dnssec-validator-requirements]. Such configuration is outside the scope of this document. Since the scope of the Homenet Authoritative Servers is limited to the home network, these servers are expected to serve the Homenet Zone as represented in Figure 1.

How the Homenet Authoritative Servers are provisioned is also out of scope of this specification. It could be implemented using primary and secondary 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 homenet interface. Note that [RFC6092] REC-8 states this must not be the default configuration. Other mechanisms may also be used.

3.2. Distribution Manager Communication Channels

This section details the DM channels, 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 DOI. The entity within the DOI responsible to handle these communications is the DM and communications between the HNA and the DM MUST be protected and mutually authenticated. While Section 4.6 discusses in more depth the different security protocols that could be used to secure, it is RECOMMENDED to use TLS with mutually authentication based on certificates to secure the channel between the HNA and the DM.

The information exchanged between the HNA and the DM uses DNS messages protected by DNS over TLS (DoT) [RFC7858]. In the future, other specifications may consider protecting DNS messages with other transport layers, among others, DNS over DTLS [RFC8094], or DNS over HTTPs (DoH) [RFC8484] or DNS over QUIC [RFC9250].

The main issue is that the Dynamic DNS update would also update the parent zone's (NS, DS and associated A or AAAA records) while the goal is to update the DM configuration files. The visible NS records SHOULD remain pointing at the cloud provider's server IP address - which in many cases will be an anycast addresses. Revealing the address of the HNA in the DNS is not desirable. Refer to Section 4.2 for more details.

This specification assumes:

  • the DM serves both the Control Channel and Synchronization Channel on a single IP address, single port and using a single transport protocol.
  • By default, the HNA uses a single IP address for both the Control and Synchronization channel. However, the HNA MAY use distinct IP addresses for the Control Channel and the Synchronization Channel - see Section 5 and Section 4.3 for more details.

The Distribution Channel is internal to the DOI and as such is not the primary concern of this specification.

4. Control Channel

The DM Control Channel is used by the HNA and the DOI to exchange information related to the configuration of the delegation which includes information to build the Public Homenet Zone (Section 4.1), information to build the DNSSEC chain of trust (Section 4.2) and information to set the Synchronization Channel (Section 4.3). While information is carried from the DOI to the HNA and from the HNA to the DOI, the HNA is always initiating the exchange in both directions.

As such the HNA has a prior knowledge of the DM identity (X509 certificate), the IP address and port number to use and protocol to set secure session. The DM acquires knowledge of the identity of the HNA (X509 certificate) as well as the Registered Homenet Domain. For more detail to see how this can be achieved, please see Appendix A.1.

4.1. Information to Build the Public Homenet Zone

The HNA builds the Public Homenet Zone based on information retrieved from the DM.

The information includes at least names and IP addresses of the Public Authoritative Name Servers. In term of RRset information this includes:

  • the MNAME of the SOA,
  • the NS and associated A and AAA RRsets of the name servers.

The DM 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 DM, 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 DOI provides this value to the parent zone. A common deployment use case is that the DOI 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 DOI 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] for transparent updates during key roll overs.

As some deployments may not provide a DOI that will be able to update the DS in the parent zone, this information exchange is OPTIONAL.

By accepting the DS RR, the DM commits in taking care of advertising the DS to the parent zone. Upon refusal, the DM clearly indicates it does not have the capacity to proceed to the update.

4.3. Information to set the Synchronization Channel

The HNA works as a primary authoritative DNS server, while the DM works like a secondary. As a result, the HNA must provide the IP address the DM is using to reach the HNA. The synchronization Channel will be set between that IP address and the IP address of the DM. By default, the IP address used by the HNA in the Control Channel is considered by the DM and the specification of the IP by the HNA is only OPTIONAL. The transport channel (including port number) is the same as the one used between the HNA and the DM for the Control Channel.

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.

The decision to delete an inactive HNA by the DM is part of the commercial agreement between DOI and HNA.

4.5. Messages Exchange Description

There are multiple ways this information could be exchanged between the HNA and the DM. This specification defines a mechanism that re-use the DNS exchanges format, while the exchange in itself is not a DNS exchange involved in any any DNS operations such as DNS resolution. 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 used as commands between the HNA and the DM.

The Control Channel is not expected to be a long-term session. After a predefined timer - similar to those used for TCP - the Control Channel is expected to be terminated - by closing the transport channel. 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 an AXFR exchange [RFC1034]. AXFR 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 [RFC2136].

To retrieve the necessary information to build the Public Homenet Zone, the HNA MUST send a 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 zero or more RRset of type A or AAAA.

  • The SOA RR indicates 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 DOI to the HNA.
  • Other RDATA values (RNAME, REFRESH, RETRY, EXPIRE and MINIMUM) are provided by the DOI as suggestions.

The NS RRsets carry the Public Authoritative Servers of the DOI. 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 format and properties of the SOA, NS and A or AAAA RRsets. If an error occurs, the HNA MUST stop proceeding and MUST log 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 DNS update message is composed of a Header section, a Zone section, a Pre-requisite section, and Update section and an additional section. The Zone section MUST set the ZNAME to the parent zone of the Registered Homenet Domain - that is where the DS records should be inserted. As described [RFC2136], ZTYPE is set to SOA and ZCLASS is set to the zone's class. The Pre-requisite section MUST be empty. The Update section is a DS RRset with its NAME set to the Registered Homenet Domain and the associated RDATA corresponds to the value of the DS. The Additional Data section MUST be empty.

Though the pre-requisite section MAY be ignored by the DM, this value is fixed to remain coherent with a standard DNS update.

Upon receiving the DNS update request, the DM reads the DS RRset in the Update section. The DM checks ZNAME corresponds to the parent zone. The DM SHOULD ignore non-empty the Pre-requisite and Additional Data section. The DM MAY update the TTL value before updating the DS RRset in the parent zone. Upon a successful update, the DM should return a NOERROR response as a commitment to update the parent zone with the provided DS. An error indicates the MD does not update the DS, and other method should be used by the HNA.

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 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.

4.5.3. Providing information for the Synchronization Channel

The default IP address used by the HNA for the Synchronization Channel is the IP address of the Control Channel. To provide a different IP address, the HNA MAY send a DNS UPDATE message.

Similarly to the Section 4.5.2, the HNA MAY specify the IP address using a DNS update message. The Zone section sets its ZNAME to the parent zone of the Registered Homenet Domain, ZTYPE is set to SOA and ZCLASS is set to the zone's type. Pre-requisite is empty. The Update section is a RRset of type NS. The Additional Data section contains the RRsets of type A or AAAA that designates the IP addresses associated to the primary (or the HNA).

The reason to provide these IP addresses is to keep them unpublished and prevent them to be resolved.

Upon receiving the DNS update request, the DM reads the IP addresses and checks the ZNAME corresponds to the parent zone. The DM SHOULD ignore a non-empty Pre-requisite section. The DM configures the secondary with the IP addresses and returns a NOERROR response to indicate it is committed to serve as a secondary.

Similarly to Section 4.5.2, DNS errors are used and an error indicates the DM is not configured as a secondary.

4.5.4. HNA instructing deleting the delegation

To instruct to delete the delegation the HNA sends a DNS UPDATE Delete message.

The Zone section sets its ZNAME to the Registered Homenet Domain, the ZTYPE to SOA and the ZCLASS to zone's type. The Pre-requisite section is empty. The Update section is a RRset of type NS with the NAME set to the Registered Domain Name. As indicated 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. The Additional Data section is empty.

Upon receiving the DNS update request, the DM checks the request and removes the delegation. The DM returns a NOERROR response to indicate the delegation has been deleted. Similarly to Section 4.5.2, DNS errors are used and an error indicates the delegation has not been deleted.

4.6. Securing the Control Channel

The control channel between the HNA and the DM MUST be secured at both the HNA and the DM.

Secure protocols (like TLS [RFC8446]) SHOULD be used to secure the transactions between the DM and the HNA.

The advantage of TLS is that this technology is widely deployed, and most of the devices already embed TLS libraries, possibly also taking advantage of hardware acceleration. Further, TLS provides authentication facilities and can use certificates to mutually authenticate the DM and HNA at the application layer, including available API. On the other hand, using TLS requires implementing DNS exchanges over TLS, as well as a new service port.

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]. The HNA is expected to be provisioned with a connection to the DM by the manufacturer, or during some user-initiated onboarding process, see Appendix A.1.

The DM SHOULD authenticate the HNA and check that inbound messages are from the appropriate client. The HNA certificate needs to provide sufficient trust to the DM that the HNA is legitimate. When certificates are used, it is left to the DM to define what information carried by the certificate is acceptable as well as which CA can issue the certificate. For example, some deployments may use domain validation certificates with the Registered Homenet Domain as a SAN of type FQDN. Other deployments may use specifically formed certificates with additional information such as a user account as a SAN of type URN, signed by a specific CA may be used.

IPsec [RFC4301] and IKEv2 [RFC7296] were considered. They would need to operate in transport mode, and the authenticated end points would need to be visible to the applications, and this is not commonly available at the time of this writing.

A pure DNS solution using TSIG and/or SIG(0) to authenticate message was also considered. Appendix A.1 envisions one mechanism would involve the end user, with a browser, signing up to a service provider, with a resulting OAUTH2 token to be provided to the HNA. A way to translate this OAUTH2 token from HTTPS web space to DNS SIG(0) space seems overly problematic, and so the enrollment protocol using web APIs was determined to be easier to implement at scale.

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 Concerns

The Hidden Primary Server on the HNA differs from a regular authoritative server for the home network due to:

Interface Binding:
the Hidden Primary Server will almost certainly listen on the WAN Interface, whereas a regular Homenet Authoritative Servers would listen on the internal home network interface.
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. This results in a limited number of possible exchanges (AXFR/IXFR) with a small number of IP addresses and an implementation SHOULD enable filtering policies as described in Section 7.

5. Synchronization Channel

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 address. Suppose the HNA and the DM are using a single IP address and let designate by XX, YYYY and ZZZZ the various ports involved in the communications. In fact the Control Channel is set between the HNA working as a client using port number YYYY (a high range port) toward a service provided by the DM at port number XX (well-known port such as 853 for DoT).

On the other hand, the Synchronization Channel is set between the DM working as a client using port ZZZZ ( a high range port) toward a service provided by the HNA at port XX.

As a result, even though the same pair of IP addresses may be involved the Control Channel and the Synchronization Channel are always distinct 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.

The use of a primary / secondary mechanism [RFC1996] is RECOMMENDED instead of the use of DNS UPDATE [RFC2136]. 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 Registered Homenet Domain Name. This secondary configuration has been previously agreed between the end user and the provider of the DOI as part of either the provisioning or due to receipt of DNS 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

The Synchronization Channel uses standard DNS requests.

First the HNA (primary) notifies the DM (secondary) that the zone must be updated and leaves the DM (secondary) to proceed with the update when possible/convenient.

More specifically, the HNA sends a NOTIFY message, which is a small packet that is less likely to load the secondary. Then, the DM sends AXFR [RFC1034] or IXFR [RFC1995] request. This request consists in a small packet sent over TCP (Section 4.2 [RFC5936]), which also mitigates reflection attacks using a forged NOTIFY.

The AXFR request from the DM to the HNA SHOULD be secured and the use of TLS is RECOMMENDED [RFC9103]. While [RFC9103] does not consider the protection by TLS of NOTIFY and SOA requests, these MAY still be protected by TLS to provide additional privacy.

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]. In addition, to guarantee the DM remains the same across multiple TLS session, the HNA and DM MAY implement [RFC8672].

The HNA SHOULD apply an ACL on inbound AXFR requests to ensure they only arrive from the DM Synchronization Channel. In this case, the HNA SHOULD regularly check (via a 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 are 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

The HNA as hidden primary processes only a limited message exchanges. This should be enforced using security policies - to allow only a subset of DNS requests to be received by HNA.

The HNA, as Hidden Primary SHOULD drop any DNS queries from the home network - as opposed to return DNS errors. This could be implemented via port binding and/or firewall rules. The precise mechanism deployed is out of scope of this document.

The HNA SHOULD drop any packets arriving on the WAN interface that are not issued from the DM - as opposed to server as an Homenet Authoritative Server exposed on the Internet.

Depending how the communications between the HNA and the DM are secured, only packets associated to that protocol SHOULD be allowed.

The HNA SHOULD NOT send DNS messages other than DNS NOTIFY query, SOA response, IXFR response or AXFR responses. The HNA SHOULD reject any incoming messages other than DNS NOTIFY response, SOA   query, IXFR query or AXFR query.

8. Homenet Reverse Zone

Homenet Reverse Zone works similarly to the Public Homenet Zone. The main difference is that ISP that provides the IP connectivity is likely also owning the corresponding reverse zone and act as a default DOI for it. If so, the configuration and the setting of the Synchronization Channel and Control Channel can largely be automated.

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 DOI 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 DOI.

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 not be so common for the Public Homenet Zone, this situation is expected to be quite common for the Reverse Homenet Zone as the ISP owns the IP address or IP prefix.

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 DOI of the associated reverse zone.

This leaves place for setting up automatically the relation between HNA and the DOI as described in [I-D.ietf-homenet-naming-architecture-dhc-options].

In the case of the reverse zone, the DOI authenticates the source of the updates by IPv6 Access Control Lists. In the case of the reverse zone, the ISP knows exactly what addresses have been delegated. The HNA SHOULD therefore always originate Synchronization Channel updates from an IP address within the zone that is being updated.

For example, if the ISP has assigned 2001:db8:f00d::/64 to the WAN interface (by DHCPv6, or PPP/RA), then the HNA should originate Synchronization Channel updates from, for example, 2001:db8:f00d::2.

An ISP that has delegated 2001:db8:aeae::/56 to the HNA via DHCPv6-PD, then HNA should originate Synchronization Channel updates an IP within that subnet, such as 2001:db8:aeae:1::2.

With this relation automatically configured, the synchronization between the Home network and the DOI happens similarly as for the Public Homenet Zone described earlier in this document.

Note that for home networks connected to by multiple ISPs, each ISP provides only the DOI 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 reverse domain space for IP addresses associated to a subnet such as ::/64 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. [RFC8501] provides guidance on how to address scalability issues.

9. 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.

It is RECOMMENDED 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 can be performed by the HNA or the DOIs and the choice highly depends on which entity is authorized to perform such updates. Typically, the DS RRset can be updated manually in the parent zone with nsupdate for example. This requires the HNA or the DOI 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 DOI. In fact, the Public Authoritative Server(s) may use Automating DNSSEC Delegation Trust Maintenance [RFC7344].

10. Renumbering

During a renumbering of the network, the HNA IP address is changed and the Public Homenet Zone is updated potentially by the HNA. Then, the HNA advertises the DM via a NOTIFY, that the Public Homenet Zone has been updated and that the IP address of the primary has been updated. This corresponds to the standard DNS procedure performed on the Synchronization Channel and no specific actions are expected for the HNA (See Section 4.3).

The remaining of the section provides recommendations regarding the provisioning of the Public Homenet Zone - especially the IP addresses. 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. 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.

In a renumbering scenario, the HNA or 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, it is RECOMMENDED that only the newly reachable IP addresses be published. Regarding the Homenet Reverse Zone, the new Homenet Reverse Zone has to be populated as soon as possible, and the old Homenet Reverse Zone will be deleted by the owner of the zone (and the owner of the old prefix which is usually the ISP) once the prefix is no longer assigned to the HNA. The ISP SHOULD ensure that the DNS cache has expired before re-assigning the prefix to a new home network. This may be enforced by controlling the TTL values.

To avoid reachability disruption, IP connectivity information provided by the DNS SHOULD be coherent with the IP in use. 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. Of course if T_NEW >= T_OLD_UNREACHABLE, the disruption is increased.

11. Privacy Considerations

Outsourcing the DNS Authoritative service from the HNA to a third party raises a few privacy related concerns.

The Public Homenet Zone lists the names of services hosted in the home network. Combined with blocking of AXFR queries, the use of NSEC3 [RFC5155] (vs NSEC [RFC4034]) prevents an attacker from being able to walk the zone, to discover all the names. However, recent work [GPUNSEC3] or [ZONEENUM] have shown that the protection provided by NSEC3 against dictionary attacks should be considered cautiously and [RFC9276] provides guidelines to configure NSEC3 properly. In addition, the attacker may be able to walk the reverse DNS zone, or use other reconnaissance techniques to learn this information as described in [RFC7707].

The zone is also exposed during the synchronization between the primary and the secondary. [RFC9103] only specifies the use of TLS for XFR transfers, which leak the existence of the zone and has been clearly specified as out of scope of the threat model of [RFC9103]. Additional privacy MAY be provided by protecting all exchanges of the Synchronization Channel as well as the Control Channel.

In general a home network owner is expected to publish only names for which there is some need to be able to reference externally. Publication of the name does not imply that the service is necessarily reachable from any or all parts of the Internet. [RFC7084] mandates that the outgoing-only policy [RFC6092] be available, and in many cases it is configured by default. A well designed User Interface would combine a policy for making a service public by a name with a policy on who may access it.

In many cases, and for privacy reasons, the home network owner wished publish names only for services that they will be able to access. The access control may consist of an IP source address range, or access may be restricted via some VPN functionality. The main advantages of publishing the name are that service may be access by the same name both within the home and outside the home and that the DNS resolution can be handled similarly within the home and outside the home. This considerably eases the ability to use VPNs where the VPN can be chosen according to the IP address of the service. Typically, a user may configure its device to reach its homenet devices via a VPN while the remaining of the traffic is accessed directly. In such cases, the routing policy is likely to be defined by the destination IP address.

Enterprise networks have generally adopted another strategy designated as split-DNS. While such strategy might appear as providing more privacy at first sight, its implementation remains challenging and the privacy advantages needs to be considered carefully. In split-DNS, names are designated with internal names that can only be resolved within the corporate network. When such strategy is applied to homenet, VPNs needs to be both configured with a naming resolution policies and routing policies. Such approach might be reasonable with a single VPN, but maintaining a coherent DNS space and IP space among various VPNs comes with serious complexities. Firstly, if multiple homenets are using the same domain name -like - it becomes difficult to determine on which network the resolution should be performed. As a result, homenets should at least be differentiated by a domain name. Secondly, the use of split-DNS requires each VPN being associated to a resolver and specific resolutions being performed by the dedicated resolver. Such policies can easily raises some conflicts (with significant privacy issues) while remaining hard to be implemented.

In addition to the Public Homenet Zone, pervasive DNS monitoring 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.

12. Security Considerations

This document exposes a mechanism that prevents the HNA from being exposed to the Internet and served DNS request from the Internet. These requests are instead served by the DOI. While this limits the level of exposure of the HNA, the HNA remains exposed to the Internet with communications with the DOI. This section analyses the attack surface associated to these communications, the data published by the DOI, as well as operational considerations.

12.1. HNA DM channels

The channels between HNA and DM are mutually authenticated and encrypted with TLS [RFC8446] and its associated security considerations apply. To ensure the multiple TLS session are continuously authenticating the same entity, TLS may take advantage of second factor authentication as described in [RFC8672].

At the time of writing TLS 1.2 or TLS 1.3 can be used and TLS 1.3 (or newer) SHOULD be supported. It is RECOMMENDED that all DNS exchanges between the HNA and the DM be protected by TLS to provide integrity protection as well as confidentiality. As noted in [RFC9103], some level of privacy may be relaxed, by not protecting the existence of the zone. This MAY involved a mix of exchanges protected by TLS and exchanges not protected by TLS. This MAY be handled by a off-line agreement between the DM and HNA as well as with the use of RCODES defined in Section 7.8 of [RFC9103].

The DNS protocol is subject to reflection attacks, however, these attacks are largely applicable when DNS is carried over UDP. The interfaces between the HNA and DM are using TLS over TCP, which prevents such reflection attacks. Note that Public Authoritative servers hosted by the DOI are subject to such attacks, but that is out of scope of our document.

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 DM and RDM may be provided by the ISP - as described in [I-D.ietf-homenet-naming-architecture-dhc-options], in which case DM and RDM might be less exposed to attacks - as communications within a network.

12.2. 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.

12.3. 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. In addition IPv6 enables temporary addresses that makes them even more volatile [RFC8981]. 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 PTR DNS queries and MAY instead be configured to return with NXDOMAIN.

12.4. Deployment Considerations

The HNA is expected to sign the DNSSEC zone and as such hold the private KSK/ZSK. To provide resilience against CPE breaks, it is RECOMMENDED to backup these keys to avoid an emergency key roll over when the CPE breaks.

The HNA enables to handle network disruption as it contains the Public Homenet Zone, which is provisioned to the Homenet Authoritative Servers. However, DNSSEC validation requires to validate the chain of trust with the DS RRset that is stored into the parent zone of the Registered Homenet Domain. As currently defined, the handling of the DS RRset is left to the Homenet DNSSEC resolver which retrieves from the parent zone via a DNS exchange and cache the RRset according to the DNS rules, that is respecting the TTL and RRSIG expiration time. Such constraints do put some limitations to the type of disruption the proposed architecture can handle. In particular, the disruption is expected to start after the DS RRset has been resolved and end before the DS RRset is removed from the cache. One possible way to address such concern is to describe mechanisms to provision the DS RRset to the Homenet DNSSEC resolver for example, via HNCP or by configuring a specific trust anchors [I-D.ietf-dnsop-dnssec-validator-requirements]. Such work is out of the scope of this document.

13. IANA Considerations

This document has no actions for IANA.

14. 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 Abrahamson, 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.

At last the authors would like to thank Kiran Makhijani for her in-depth review that contributed in shaping the final version.

15. Contributors

The co-authors would like to thank Chris Griffiths and Wouter Cloetens that provided a significant contribution in the early versions of the document.

16. References

16.1. Normative References

Mockapetris, P., "Domain names - concepts and facilities", STD 13, RFC 1034, DOI 10.17487/RFC1034, , <>.
Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G. J., and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918, , <>.
Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, DOI 10.17487/RFC1995, , <>.
Vixie, P., "A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)", RFC 1996, DOI 10.17487/RFC1996, , <>.
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, DOI 10.17487/RFC4034, , <>.
Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS Security (DNSSEC) Hashed Authenticated Denial of Existence", RFC 5155, DOI 10.17487/RFC5155, , <>.
Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol (AXFR)", RFC 5936, DOI 10.17487/RFC5936, , <>.
Kumari, W., Gudmundsson, O., and G. Barwood, "Automating DNSSEC Delegation Trust Maintenance", RFC 7344, DOI 10.17487/RFC7344, , <>.
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, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
Pfister, P. and T. Lemon, "Special-Use Domain ''", RFC 8375, DOI 10.17487/RFC8375, , <>.
Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, , <>.
Toorop, W., Dickinson, S., Sahib, S., Aras, P., and A. Mankin, "DNS Zone Transfer over TLS", RFC 9103, DOI 10.17487/RFC9103, , <>.

16.2. Informative References

"ddclient", n.d., <>.
Wander, M., Schwittmann, L., Boelmann, C., and T. Weis, "GPU-Based NSEC3 Hash Breaking", n.d., <>.
Migault, D. and D. York, "Recommendations for DNSSEC Resolvers Operators", Work in Progress, Internet-Draft, draft-ietf-dnsop-dnssec-validator-requirements-01, , <>.
Migault, D., Weber, R., and T. Mrugalski, "DHCPv6 Options for Home Network Naming Authority", Work in Progress, Internet-Draft, draft-ietf-homenet-naming-architecture-dhc-options-18, , <>.
Richardson, M., "Provisioning Initial Device Identifiers into Home Routers", Work in Progress, Internet-Draft, draft-richardson-homerouter-provisioning-02, , <>.
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, , <>.
Wellington, B., "Secure Domain Name System (DNS) Dynamic Update", RFC 3007, DOI 10.17487/RFC3007, , <>.
Parker, J., Ed., "Recommendations for Interoperable IP Networks using Intermediate System to Intermediate System (IS-IS)", RFC 3787, DOI 10.17487/RFC3787, , <>.
Cheshire, S., Aboba, B., and E. Guttman, "Dynamic Configuration of IPv4 Link-Local Addresses", RFC 3927, DOI 10.17487/RFC3927, , <>.
Baker, F., Lear, E., and R. Droms, "Procedures for Renumbering an IPv6 Network without a Flag Day", RFC 4192, DOI 10.17487/RFC4192, , <>.
Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast Addresses", RFC 4193, DOI 10.17487/RFC4193, , <>.
Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, DOI 10.17487/RFC4291, , <>.
Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, , <>.
Woodyatt, J., Ed., "Recommended Simple Security Capabilities in Customer Premises Equipment (CPE) for Providing Residential IPv6 Internet Service", RFC 6092, DOI 10.17487/RFC6092, , <>.
Hoffman, P. and J. Schlyter, "The DNS-Based Authentication of Named Entities (DANE) Transport Layer Security (TLS) Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, , <>.
Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, , <>.
Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, DOI 10.17487/RFC6762, , <>.
Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and P. Selkirk, "Port Control Protocol (PCP)", RFC 6887, DOI 10.17487/RFC6887, , <>.
Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W. George, "IPv6 Site Renumbering Gap Analysis", RFC 7010, DOI 10.17487/RFC7010, , <>.
Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic Requirements for IPv6 Customer Edge Routers", RFC 7084, DOI 10.17487/RFC7084, , <>.
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, , <>.
Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J. Weil, "IPv6 Home Networking Architecture Principles", RFC 7368, DOI 10.17487/RFC7368, , <>.
Behringer, M. and E. Vyncke, "Using Only Link-Local Addressing inside an IPv6 Network", RFC 7404, DOI 10.17487/RFC7404, , <>.
Gont, F. and T. Chown, "Network Reconnaissance in IPv6 Networks", RFC 7707, DOI 10.17487/RFC7707, , <>.
Stenberg, M., Barth, S., and P. Pfister, "Home Networking Control Protocol", RFC 7788, DOI 10.17487/RFC7788, , <>.
Reddy, T., Wing, D., and P. Patil, "DNS over Datagram Transport Layer Security (DTLS)", RFC 8094, DOI 10.17487/RFC8094, , <>.
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, , <>.
Hoffman, P. and P. McManus, "DNS Queries over HTTPS (DoH)", RFC 8484, DOI 10.17487/RFC8484, , <>.
Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499, , <>.
Howard, L., "Reverse DNS in IPv6 for Internet Service Providers", RFC 8501, DOI 10.17487/RFC8501, , <>.
Barnes, R., Hoffman-Andrews, J., McCarney, D., and J. Kasten, "Automatic Certificate Management Environment (ACME)", RFC 8555, DOI 10.17487/RFC8555, , <>.
Birkholz, H., Vigano, C., and C. Bormann, "Concise Data Definition Language (CDDL): A Notational Convention to Express Concise Binary Object Representation (CBOR) and JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, , <>.
Sheffer, Y. and D. Migault, "TLS Server Identity Pinning with Tickets", RFC 8672, DOI 10.17487/RFC8672, , <>.
Gont, F., Krishnan, S., Narten, T., and R. Draves, "Temporary Address Extensions for Stateless Address Autoconfiguration in IPv6", RFC 8981, DOI 10.17487/RFC8981, , <>.
Huitema, C., Dickinson, S., and A. Mankin, "DNS over Dedicated QUIC Connections", RFC 9250, DOI 10.17487/RFC9250, , <>.
Hardaker, W. and V. Dukhovni, "Guidance for NSEC3 Parameter Settings", BCP 236, RFC 9276, DOI 10.17487/RFC9276, , <>.
Wang, Z., Xiao, L., and R. Wang, "An efficient DNSSEC zone enumeration algorithm", n.d..

Appendix A. HNA Channel Configurations

A.1. Homenet Public Zone

This document does not deal with how the HNA is provisioned with a trusted relationship to the Distribution Manager for the forward zone.

This section details what needs to be provisioned into the HNA and serves as a requirements statement for mechanisms.

The HNA needs to be provisioned with:

  • the Registered Domain (e.g., myhome.example )
  • the contact info for the Distribution Manager (DM), including the DNS name (FQDN), possibly including the IP literal, and a certificate (or anchor) to be used to authenticate the service
  • the DM transport protocol and port (the default is DNS over TLS, on port 853)
  • the HNA credentials used by the DM for its authentication.

The HNA will need to select an IP address for communication for the Synchronization Channel. This is typically the WAN address of the CPE, but could be an IPv6 LAN address in the case of a home with multiple ISPs (and multiple border routers). This is detailed in Section 4.5.3 when the NS and A or AAAA RRsets are communicated.

The above parameters MUST be be provisioned for ISP-specific reverse zones, as per [I-D.ietf-homenet-naming-architecture-dhc-options]. ISP-specific forward zones MAY also be provisioned using [I-D.ietf-homenet-naming-architecture-dhc-options], but zones which are not related to a specific ISP zone (such as with a DNS provider) must be provisioned through other means.

Similarly, if the HNA is provided by a registrar, the HNA may be handed pre-configured to end user.

In the absence of specific pre-established relation, these pieces of information may be entered manually by the end user. In order to ease the configuration from the end user the following scheme may be implemented.

The HNA may present the end user a web interface where it provides the end user the ability to indicate the Registered Homenet Domain or the registrar for example a preselected list. Once the registrar has been selected, the HNA redirects the end user to that registrar in order to receive a access token. The access token will enable the HNA to retrieve the DM parameters associated to the Registered Domain. These parameters will include the credentials used by the HNA to establish the Control and Synchronization Channels.

Such architecture limits the necessary steps to configure the HNA from the end user.

Appendix B. Information Model for Outsourced information

This section is non-normative and specifies an optional format for the set of parameters required by the HNA to configure the naming architecture of this document.

In cases where a home router has not been provisioned by the manufacturer (when forward zones are provided by the manufacturer), or by the ISP (when the ISP provides this service), then a home user/owner will need to configure these settings via an administrative interface.

By defining a standard format (in JSON) for this configuration information, the user/owner may be able to just copy and paste a configuration blob from the service provider into the administrative interface of the HNA.

This format may also provide the basis for a future OAUTH2 [RFC6749] flow that could do the setup automatically.

The HNA needs to be configured with the following parameters as described by this CDDL [RFC8610]. These are the 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.

hna-configuration = {
  "registered_domain" : tstr,
  "dm"                : tstr,
  ? "dm_transport" : "DoT"
  ? "dm_port"        : uint,
  ? "dm_acl"         : hna-acl / [ +hna-acl ]
  ? "hna_auth_method": hna-auth-method
  ? "hna_certificate": tstr

hna-acl          = tstr
hna-auth-method  /= "certificate"

For example:

  "registered_domain" : "",
  "dm"                : "2001:db8:1234:111:222::2",
  "dm_transport"      : "DoT",
  "dm_port"           : 4433,
  "dm_acl"            : "2001:db8:1f15:62e:21c::/64"
                   or [ "2001:db8:1f15:62e:21c::/64", ... ]
  "hna_auth_method"   : "certificate",
  "hna_certificate"   : "-----BEGIN CERTIFICATE-----\nMIIDTjCCFGy....",
Registered Homenet Domain (zone)
The Domain Name of the zone. Multiple Registered Homenet Domains may be provided. This will generate the creation of multiple Public Homenet Zones. This parameter is MANDATORY.
Distribution Manager notification address (dm)
The associated FQDNs or IP addresses of the DM to which DNS notifies should be sent. This parameter is MANDATORY. IP addresses are optional and the FQDN is sufficient and preferred. If there are concerns about the security of the name to IP translation, then DNSSEC should be employed.

As the session between the HNA and the DM is authenticated with TLS, the use of names is easier.

As certificates are more commonly emitted for FQDN than for IP addresses, it is preferred to use names and authenticate the name of the DM during the TLS session establishment.

Supported Transport (dm_transport)
The transport that carries the DNS exchanges between the HNA and the DM. Typical value is "DoT" but it may be extended in the future with "DoH", "DoQ" for example. This parameter is OPTIONAL and by default the HNA uses DoT.
Distribution Manager Port (dm_port)
Indicates the port used by the DM. This parameter is OPTIONAL and the default value is provided by the Supported Transport. In the future, additional transport may not have default port, in which case either a default port needs to be defined or this parameter become MANDATORY.

Note that HNA does not defines ports for the Synchronization Channel. In any case, this is not expected to part of the configuration, but instead negotiated through the Configuration Channel. Currently the Configuration Channel does not provide this, and limits its agility to a dedicated IP address. If such agility is needed in the future, additional exchanges will need to be defined.

Authentication Method ("hna_auth_method"):
How the HNA authenticates itself to the DM within the TLS connection(s). The authentication meth of can typically be "certificate", "psk" or "none". This Parameter is OPTIONAL and by default the Authentication Method is "certificate".

Authentication data ("hna_certificate", "hna_key"): : The certificate chain used to authenticate the HNA. This parameter is OPTIONAL and when not specified, a self-signed certificate is used.

Distribution Manager AXFR permission netmask (dm_acl):
The subnet from which the CPE should accept SOA queries and AXFR requests. A subnet is used in the case where the DOI consists of a number of different systems. An array of addresses is permitted. This parameter is OPTIONAL and if unspecified, the CPE uses the IP addresses provided by the dm parameter either directly when dm indicates an IP address or the IP addresses returned by the DNS(SEC) resolution when dm indicates a FQDN.

For forward zones, the relationship between the HNA and the forward zone provider may be the result of a number of transactions:

  1. The forward zone outsourcing may be provided by the maker of the Homenet router. In this case, the identity and authorization could be built in the device at manufacturer provisioning time. The device would need to be provisioned with a device-unique credential, and it is likely that the Registered Homenet Domain would be derived from a public attribute of the device, such as a serial number (see Appendix C or [I-D.richardson-homerouter-provisioning] for more details ).
  2. The forward zone outsourcing may be provided by the Internet Service Provider. In this case, the use of [I-D.ietf-homenet-naming-architecture-dhc-options] to provide the credentials is appropriate.
  3. The forward zone may be outsourced to a third party, such as a domain registrar. In this case, the use of the JSON-serialized YANG data model described in this section is appropriate, as it can easily be copy and pasted by the user, or downloaded as part of a web transaction.

For reverse zones, the relationship is always with the upstream ISP (although there may be more than one), and so [I-D.ietf-homenet-naming-architecture-dhc-options] is always the appropriate interface.

The following is an abbridged example of a set of data that represents the needed configuration parameters for outsourcing.

Appendix C. Example: A manufacturer provisioned HNA product flow

This scenario is one where a homenet router device manufacturer decides to offer DNS hosting as a value add.

[I-D.richardson-homerouter-provisioning] describes a process for a home router credential provisioning system. The outline of it is that near the end of the manufacturing process, as part of the firmware loading, the manufacturer provisions a private key and certificate into the device.

In addition to having a assymmetric credential known to the manufacturer, the device also has been provisioned with an agreed upon name. In the example in the above document, the name "" has already been allocated and confirmed with the manufacturer.

The HNA can use the above domain for itself. It is not very pretty or personal, but if the owner wishes a better name, they can arrange for it.

The configuration would look like:

  "dm" : "2001:db8:1234:111:222::2",
  "dm_acl"    : "2001:db8:1234:111:222::/64",
  "dm_ctrl"   : "",
  "dm_port"   : "4433",
  "ns_list"   : [ "ns1.publicdns.example", "ns2.publicdns.example"],
  "zone"      : "",
  "auth_method" : "certificate",
  "hna_certificate":"-----BEGIN CERTIFICATE-----\nMIIDTjCCFGy....",

The dm_ctrl and dm_port values would be built into the firmware.

Authors' Addresses

Daniel Migault
8275 Trans Canada Route
Saint Laurent, QC 4S 0B6
Ralf Weber
2000 Seaport Blvd
Redwood City, 94063
United States of America
Michael Richardson
Sandelman Software Works
470 Dawson Avenue
Ottawa, ON K1Z 5V7
Ray Hunter
Globis Consulting BV
Weegschaalstraat 3
5632CW Eindhoven