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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Homenet D. Migault 3 Internet-Draft Ericsson 4 Intended status: Standards Track R. Weber 5 Expires: October 30, 2021 Nominum 6 M. Richardson 7 Sandelman Software Works 8 R. Hunter 9 Globis Consulting BV 10 April 28, 2021 12 Simple Provisioning of Public Names for Residential Networks 13 draft-ietf-homenet-front-end-naming-delegation-14 15 Abstract 17 Home owners often have IPv6 devices that they wish to access over the 18 Internet using names. It has been possible to register and populate 19 a DNS Zone with names since DNS became a thing, but it has been an 20 activity typically reserved for experts. This document automates the 21 process through creation of a Homenet Naming Authority (HNA), whose 22 responsibility is to select, sign and publish names to a set of 23 publicly visible servers. 25 The use of an outsourced primary DNS server deals with possible 26 renumbering of the home network, and with possible denial of service 27 attacks against the DNS infrastructure. 29 This document describes the mechanism that enables the HNA to 30 outsource the naming service to the DNS Outsourcing Infrastructure 31 (DOI) via a Distribution Master (DM). 33 In addition, this document deals with publication of a corresponding 34 reverse zone. 36 Status of This Memo 38 This Internet-Draft is submitted in full conformance with the 39 provisions of BCP 78 and BCP 79. 41 Internet-Drafts are working documents of the Internet Engineering 42 Task Force (IETF). Note that other groups may also distribute 43 working documents as Internet-Drafts. The list of current Internet- 44 Drafts is at https://datatracker.ietf.org/drafts/current/. 46 Internet-Drafts are draft documents valid for a maximum of six months 47 and may be updated, replaced, or obsoleted by other documents at any 48 time. It is inappropriate to use Internet-Drafts as reference 49 material or to cite them other than as "work in progress." 51 This Internet-Draft will expire on October 30, 2021. 53 Copyright Notice 55 Copyright (c) 2021 IETF Trust and the persons identified as the 56 document authors. All rights reserved. 58 This document is subject to BCP 78 and the IETF Trust's Legal 59 Provisions Relating to IETF Documents 60 (https://trustee.ietf.org/license-info) in effect on the date of 61 publication of this document. Please review these documents 62 carefully, as they describe your rights and restrictions with respect 63 to this document. Code Components extracted from this document must 64 include Simplified BSD License text as described in Section 4.e of 65 the Trust Legal Provisions and are provided without warranty as 66 described in the Simplified BSD License. 68 Table of Contents 70 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 71 1.1. Selecting Names to Publish . . . . . . . . . . . . . . . 5 72 1.2. Alternative solutions . . . . . . . . . . . . . . . . . . 6 73 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7 74 3. Architecture Description . . . . . . . . . . . . . . . . . . 8 75 3.1. Architecture Overview . . . . . . . . . . . . . . . . . . 9 76 3.2. Distribution Master Communication Channels . . . . . . . 11 77 4. Control Channel between Homenet Naming Authority (HNA) and 78 Distribution Master (DM) . . . . . . . . . . . . . . . . . . 13 79 4.1. Information to build the Public Homenet Zone . . . . . . 13 80 4.2. Information to build the DNSSEC chain of trust . . . . . 13 81 4.3. Information to set the Synchronization Channel . . . . . 14 82 4.4. Deleting the delegation . . . . . . . . . . . . . . . . . 14 83 4.5. Messages Exchange Description . . . . . . . . . . . . . . 14 84 4.5.1. Retrieving information for the Public Homenet Zone. . 15 85 4.5.2. Providing information for the DNSSEC chain of trust . 16 86 4.5.3. Providing information for the Synchronization Channel 16 87 4.5.4. HNA instructing deleting the delegation . . . . . . . 17 88 4.6. Securing the Control Channel between Homenet Naming 89 Authority (HNA) and Distribution Master (DM) . . . . . . 17 90 4.7. Implementation Concerns . . . . . . . . . . . . . . . . . 18 91 5. DM Synchronization Channel between HNA and DM . . . . . . . . 19 92 5.1. Securing the Synchronization Channel between HNA and DM . 20 93 6. DM Distribution Channel . . . . . . . . . . . . . . . . . . . 20 94 7. HNA Security Policies . . . . . . . . . . . . . . . . . . . . 21 95 8. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 21 96 9. Homenet Reverse Zone Channels Configuration . . . . . . . . . 21 97 10. Homenet Public Zone Channel Configurations . . . . . . . . . 23 98 11. Renumbering . . . . . . . . . . . . . . . . . . . . . . . . . 24 99 11.1. Hidden Primary . . . . . . . . . . . . . . . . . . . . . 24 100 12. Privacy Considerations . . . . . . . . . . . . . . . . . . . 25 101 13. Security Considerations . . . . . . . . . . . . . . . . . . . 26 102 13.1. HNA DM channels . . . . . . . . . . . . . . . . . . . . 26 103 13.2. Names are less secure than IP addresses . . . . . . . . 27 104 13.3. Names are less volatile than IP addresses . . . . . . . 27 105 14. Information Model for Outsourced information . . . . . . . . 27 106 14.1. Outsourced Information Model . . . . . . . . . . . . . . 28 107 15. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30 108 16. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 30 109 17. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 31 110 18. References . . . . . . . . . . . . . . . . . . . . . . . . . 31 111 18.1. Normative References . . . . . . . . . . . . . . . . . . 31 112 18.2. Informative References . . . . . . . . . . . . . . . . . 34 113 Appendix A. Envisioned deployment scenarios . . . . . . . . . . 36 114 A.1. CPE Vendor . . . . . . . . . . . . . . . . . . . . . . . 36 115 A.2. Agnostic CPE . . . . . . . . . . . . . . . . . . . . . . 36 116 Appendix B. Example: A manufacturer provisioned HNA product flow 37 117 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 119 1. Introduction 121 The Homenet Naming Authority (HNA) is responsible for making devices 122 within the home network accessible by name within the home network as 123 well as from outside the home network (e.g. the Internet). IPv6 124 connectivity provides the possibility of global end to end IP 125 connectivity. End users will be able to transparently make use of 126 this connectivity if they can use names to access the services they 127 want from their home network. 129 The use of a DNS zone for each home network is a reasonable and 130 scalable way to make the set of public names visible. There are a 131 number of ways to populate such a zone. This specification proposes 132 a way based on a number of assumptions about typical home networks. 134 1. The names of the devices accessible from the Internet are stored 135 in the Public Homenet Zone, served by a DNS authoritative server. 137 2. It is unlikely that home networks will contain sufficiently 138 robust platforms designed to host a service such as the DNS on 139 the Internet and as such would expose the home network to DDoS 140 attacks. 142 3. [RFC7368] emphasizes that the home network is subject to 143 connectivity disruptions with the ISP. But, names used within 144 the home MUST be resilient against such disruption. 146 This specification makes the public names resolvable within both the 147 home network and on the Internet, even when there are disruptions. 149 This is achieved by having a device inside the home network that 150 builds, signs, publishes, and manages a Public Homenet Zone, thus 151 providing bindings between public names, IP addresses, and other RR 152 types. 154 The management of the names can be a role that the Customer Premises 155 Equipment (CPE) does. Other devices in the home network could 156 fulfill this role e.g. a NAS server, but for simplicity, this 157 document assumes the function is located on one of the CPE devices. 159 The homenet architecture [RFC7368] makes it clear that a home network 160 may have multiple CPEs. The management of the Public Homenet Zone 161 involves DNS specific mechanisms that cannot be distributed over 162 multiple servers (primary server), when multiple nodes can 163 potentially manage the Public Homenet Zone, a single node needs to be 164 selected per outsourced zone. This selected node is designated as 165 providing the HNA function. 167 The process by which a single HNA is selected per zone is not in 168 scope for this document. It is envisioned that a future document 169 will describe an HNCP mechanism to elect the single HNA. 171 CPEs, which may host the HNA function, as well as home network 172 devices, are usually low powered devices not designed for terminating 173 heavy traffic. As a result, hosting an authoritative DNS service 174 visible to the Internet may expose the home network to resource 175 exhaustion and other attacks. On the other hand, if the only copy of 176 the public zone is on the Internet, then Internet connectivity 177 disruptions would make the names unavailable inside the homenet. 179 In order to avoid resource exhaustion and other attacks, this 180 document describes an architecture that outsources the authoritative 181 naming service of the home network. More specifically, the HNA 182 builds the Public Homenet Zone and outsources it to an DNS 183 Outsourcing Infrastructure (DOI) via a Distribution Master (DM). The 184 DOI is in charge of publishing the corresponding Public Homenet Zone 185 on the Internet. The transfer of DNS zone information is achieved 186 using standard DNS mechanisms involving primary and secondary DNS 187 servers, with the HNA hosted primary being a stealth primary, and the 188 DM a secondary. 190 Section 3.1 provides an architecture description that describes the 191 relation between the HNA and the DOI. In order to keep the Public 192 Homenet Zone up-to-date Section 5 describes how the HNA and the DOI 193 synchronizes the Pubic Homenet Zone. 195 The proposed architecture is explicitly designed to enable fully 196 functional DNSSEC, and the Public Homenet Zone is expected to be 197 signed with a secure delegation. DNSSEC key management and zone 198 signing is handled by the HNA. 200 Section 10 discusses management and configuration of the Public 201 Homenet Zone. It shows that the HNA configuration of the DOI can 202 involve no or little interaction with the end user. More 203 specifically, it shows that the existence of an account in the DOI is 204 sufficient for the DOI to push the necessary configuration. In 205 addition, when the DOI and CPE are both managed by an ISP, the 206 configuration can be entirely automated - see Section 9. 208 Section 9 discusses management of one or more reverse zones. It 209 shows that management of the reverse zones can be entirely automated 210 and benefit from a pre-established relation between the ISP and the 211 home network. Note that such scenarios may also be met for the 212 Public Homenet Zone, but not necessarily. 214 Section 11 discusses how renumbering should be handled. Finally, 215 Section 12 and Section 13 respectively discuss privacy and security 216 considerations when outsourcing the Public Homenet Zone. 218 The Public Homenet Zone is expected to contain public information 219 only in a single universal view. This document does not define how 220 the information required to construct this view is derived. 222 It is also not in the scope of this document to define names for 223 exclusive use within the boundaries of the local home network. 224 Instead, local scope information is expected to be provided to the 225 home network using local scope naming services. mDNS [RFC6762] DNS-SD 226 [RFC6763] are two examples of these services. Currently mDNS is 227 limited to a single link network. However, future protocols and 228 architectures [I-D.ietf-homenet-simple-naming] are expected to 229 leverage this constraint as pointed out in [RFC7558]. 231 1.1. Selecting Names to Publish 233 While this document does not create any normative mechanism by which 234 the selection of names to publish, this document anticipates that the 235 home network administrator (a humuan), will be presented with a list 236 of current names and addresses present on the inside of the home 237 network. 239 The administrator would mark which devices (by name), are to be 240 published. The HNA would then collect the IPv6 address(es) 241 associated with that device, and put the name into the Public Homenet 242 Zone. The address of the device can be collected from a number of 243 places: mDNS [RFC6762], DHCP [RFC6644], UPnP, PCP [RFC6887], or 244 manual configuration. 246 A device may have a Global Unicast Address (GUA), a Unique Local IPv6 247 Address (ULA), as as well IPv6-Link-Local addresses, IPv4-Link-Local 248 Addresses, and RFC1918 addresses. Of these the link-local are never 249 useful for the Public Zone, and should be omitted. The IPv6 ULA and 250 the RFC1918 addresses may be useful to publish, if the home network 251 environment features a VPN that would allow the home owner to reach 252 the network. 254 The IPv6 ULA addressees are significantly safer to publish, as the 255 RFC1918 addressees are likely to be confusing to any other entity. 257 In general, one expects the GUA to be the default address to be 258 published. However, during periods when the home network has 259 connectivity problems, the ULA and RFC1918 addressees can be used 260 inside the home, and the mapping from public name to locally useful 261 location address would permit many services secured with HTTPS to 262 continue to operate. 264 1.2. Alternative solutions 266 An alternative existing solution in IPv4 is to have a single zone, 267 where a host uses a RESTful HTTP service to register a single name 268 into a common public zone. This is often called "Dynamic DNS", and 269 there are a number of commercial providers, including Dyn, Gandi etc. 270 These solutions were typically used by a host behind the CPE to make 271 it's CPE IPv4 address visible, usually in order to enable incoming 272 connections. 274 For a small number (one to three) of hosts, use of such a system 275 provides an alternative to the architecture described in this 276 document. 278 The alternative does suffer from some severe limitations: 280 o the CPE/HNA router is unaware of the process, and cannot respond 281 to queries for these names when there are disruptions in 282 connectivity. This makes the home user or application dependent 283 on having to resolve different names in the event of outages or 284 disruptions. 286 o the CPE/HNA router cannot control the process. Any host can do 287 this regardless of whether or not the home network administrator 288 wants the name published or not. There is therefore no possible 289 audit trail. 291 o the credentials for the dynamic DNS server need to be securely 292 transferred to all hosts that wish to use it. This is not a 293 problem for a technical user to do with one or two hosts, but it 294 does not scale to multiple hosts and becomes a problem for non- 295 technical users. 297 o "all the good names are taken" - current services put everyone's 298 names into some small set of zones, and there are often conflicts. 299 Distinguishing similar names by delegation of zones was among the 300 primary design goals of the DNS system. 302 o The RESTful services do not always support all RR types. The 303 homenet user is dependent on the service provider supporting new 304 types. By providing full DNS delegation, this document enables 305 all RR types and also future extensions. 307 There is no technical reason why a RESTful cloud service could not 308 provide solutions to many of these problems, but this document 309 describes a DNS based solution. 311 2. Terminology 313 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 314 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 315 "OPTIONAL" in this document are to be interpreted as described in 316 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all 317 capitals, as shown here. 319 Customer Premises Equipment: (CPE) is a router providing 320 connectivity to the home network. 322 Homenet Zone: is the DNS zone for use within the boundaries of the 323 home network: home.arpa, see [RFC8375]). This zone is not 324 considered public and is out of scope for this document. 326 Registered Homenet Domain: is the Domain Name associated with the 327 home network. 329 Public Homenet Zone: contains the names in the home network that are 330 expected to be publicly resolvable on the Internet. 332 Homenet Naming Authority: (HNA) is a function responsible for 333 managing the Public Homenet Zone. This includes populating the 334 Public Homenet Zone, signing the zone for DNSSEC, as well as 335 managing the distribution of that Homenet Zone to the DNS 336 Outsourcing Infrastructure (DOI). 338 DNS Outsourcing Infrastructure (DOI): is the infrastructure 339 responsible for receiving the Public Homenet Zone and publishing 340 it on the Internet. It is mainly composed of a Distribution 341 Master and Public Authoritative Servers. 343 Public Authoritative Servers: are the authoritative name servers for 344 the Public Homenet Zone. Name resolution requests for the Homenet 345 Domain are sent to these servers. For resiliency the Public 346 Homenet Zone SHOULD be hosted on multiple servers. 348 Homenet Authoritative Servers: are authoritative name servers within 349 the Homenet network. 351 Distribution Master (DM): is the (set of) server(s) to which the HNA 352 synchronizes the Public Homenet Zone, and which then distributes 353 the relevant information to the Public Authoritative Servers. 355 Homenet Reverse Zone: The reverse zone file associated with the 356 Public Homenet Zone. 358 Reverse Public Authoritative Servers: equivalent to Public 359 Authoritative Servers specifically for reverse resolution. 361 Reverse Distribution Master: equivalent to Distribution Master 362 specifically for reverse resolution. 364 Homenet DNSSEC Resolver: a resolver that performs a DNSSEC 365 resolution on the home network for the Public Homenet Zone. The 366 resolution is performed requesting the Homenet Authoritative 367 Servers. 369 DNSSEC Resolver: a resolver that performs a DNSSEC resolution on the 370 Internet for the Public Homenet Zone. The resolution is performed 371 requesting the Public Authoritative Servers. 373 3. Architecture Description 375 This section provides an overview of the architecture for outsourcing 376 the authoritative naming service from the HNA to the DOI in 377 Section 3.1. Section 14 defines necessary parameter to configure the 378 HNA. 380 3.1. Architecture Overview 382 Figure 1 illustrates the architecture where the HNA outsources the 383 publication of the Public Homenet Zone to the DOI. 385 The Public Homenet Zone is identified by the Registered Homenet 386 Domain Name - myhome.example. The ".local" as well as ".home.arpa" 387 are explicitly not considered as Public Homenet zones and represented 388 as Homenet Zone in Figure 1. 390 The HNA SHOULD build the Public Homenet Zone in a single view 391 populated with all resource records that are expected to be published 392 on the Internet. As explained in Section 1.1, how the Public Homenet 393 Zone is populated is out of the scope of this document. The HNA also 394 signs the Public Homenet Zone. The HNA handles all operations and 395 keying material required for DNSSEC, so there is no provision made in 396 this architecture for transferring private DNSSEC related keying 397 material between the HNA and the DM. 399 Once the Public Homenet Zone has been built, the HNA outsources it to 400 the DOI as described in Figure 1. The HNA acts as a hidden primary 401 while the DM behaves as a secondary responsible to distribute the 402 Public Homenet Zone to the multiple Public Authoritative Servers that 403 DOI is responsible for. The DM has 3 communication channels: 405 o a DM Control Channel (see section Section 4) to configure the HNA 406 and the DOI, 408 o a DM Synchronization Channel (see section Section 5 to synchronize 409 the Public Homenet Zone on the HNA and on the DM. 411 o one or more Distribution Channels (see section Section 6 that 412 distributes the Public Homenet Zone from the DM to the Public 413 Authoritative Server serving the Public Homenet Zone on the 414 Internet. 416 There MAY be multiple DM's, and multiple servers per DM. This text 417 assumes a single DM server for simplicity, but there is no reason why 418 each channel needs to be implemented on the same server, or indeed 419 use the same code base. 421 It is important to note that while the HNA is configured as an 422 authoritative server, it is not expected to answer to DNS requests 423 from the public Internet for the Public Homenet Zone. More 424 specifically, the addresses associated with the HNA SHOULD NOT be 425 mentioned in the NS records of the Public Homenet zone, unless 426 additional security provisions necessary to protect the HNA from 427 external attack have been taken. 429 The DOI is also responsible for ensuring the DS record has been 430 updated in the parent zone. 432 Resolution is performed by the DNSSEC resolvers. When the resolution 433 is performed outside the home network, the DNSSEC Resolver resolves 434 the DS record on the Global DNS and the name associated to the Public 435 Homenet Zone (myhome.example) on the Public Authoritative Servers. 437 When the resolution is performed from within the home network, the 438 Homenet DNSSEC Resolver may proceed similarly. On the other hand, to 439 provide resilience to the Public Homenet Zone in case of disruption, 440 the Homenet DNSSEC Resolver SHOULD be able to perform the resolution 441 on the Homenet Authoritative Servers. These servers are not expected 442 to be mentioned in the Public Homenet Zone, nor to be accessible from 443 the Internet. As such their information as well as the corresponding 444 signed DS record MAY be provided by the HNA to the Homenet DNSSEC 445 Resolvers, e.g., using HNCP [RFC7788]. Such configuration is outside 446 the scope of this document. Since the scope of the Homenet 447 Authoritative Servers is limited to the home network, these servers 448 are expected to serve the Homenet Zone as represented in Figure 1. 450 How the Homenet Authoritative Servers are provisioned is also out of 451 scope of this specification. It could be implemented using primary 452 secondaries servers, or via rsync. In some cases, the HNA and 453 Homenet Authoritative Servers may be combined together which would 454 result in a common instantiation of an authoritative server on the 455 WAN and inner interface. Other mechanisms may also be used. 457 Home network | Internet 458 | 459 | +----------------------------+ 460 | | DOI | 461 Control | | | 462 +-----------------------+ Channel | | +-----------------------+ | 463 | HNA |<-------------->| Distribution Master | | 464 |+---------------------+| | | |+---------------------+| | 465 || Public Homenet Zone ||Synchronization || Public Homenet Zone || | 466 || (myhome.example) || Channel | | || (myhome.example) || | 467 |+---------------------+|<-------------->|+---------------------+| | 468 +-----------^-----------+ | | +-----------------------+ | 469 . | | ^ Distribution | 470 . | | | Channel | 471 +-----------v-----------+ | | v | 472 | Homenet Authoritative | | | +-----------------------+ | 473 | Server(s) | | | | Public Authoritative | | 474 |+---------------------+| | | | Server(s) | | 475 ||Public Homenet Zone || | | |+---------------------+| | 476 || (myhome.example) || | | || Public Homenet Zone || | 477 |+---------------------+| | | || (myhome.example) || | 478 || Homenet Zone || | | |+---------------------+| | 479 || (home.arpa) || | | +-----------------------+ | 480 |+---------------------+| | +----------^---|-------------+ 481 +----------^---|--------+ | | | 482 | | name resolution | | 483 | v | | v 484 +----------------------+ | +-----------------------+ 485 | Homenet | | | Internet | 486 | DNSSEC Resolver | | | DNSSEC Resolver | 487 +----------------------+ | +-----------------------+ 489 Figure 1: Homenet Naming Architecture 491 3.2. Distribution Master Communication Channels 493 This section details the interfaces and channels of the DM, that is 494 the Control Channel, the Synchronization Channel and the Distribution 495 Channel. 497 The Control Channel and the Synchronization Channel are the 498 interfaces used between the HNA and the DOI. The entity within the 499 DOI responsible to handle these communications is the DM and 500 communications between the HNA and the DM SHOULD be protected and 501 mutually authenticated. While section Section 4.6 discusses in more 502 depth the different security protocols that could be used to secure, 503 this specification RECOMMENDS the use of TLS with mutually 504 authentication based on certificates to secure the channel between 505 the HNA and the DM. 507 The Control Channel is used to set up the Synchronization Channel. 508 We assume that the HNA initiates the Control Channel connection with 509 the DM and as such has a prior knowledge of the DM identity (X509 510 certificate), the IP address and port to use and protocol to set 511 secure session. We also assume the DM has knowledge of the identity 512 of the HNA (X509 certificate) as well as the Registered Homenet 513 Domain. For more detail to see how this can be achieved, please see 514 section Section 10. 516 The information exchanged between the HNA and the DM is using DNS 517 messages protected by DNS over TLS (DoT) [RFC7858]. Further 518 specifications may consider protecting DNS messages with other 519 transport layers, among others, DNS over DTLS [RFC8094], or DNS over 520 HTTPs (DoH) [RFC8484] or DNS over QUIC [I-D.ietf-dprive-dnsoquic]. 521 There was consideration to using a standard TSIG [RFC2845] or SIG(0) 522 [RFC2931] to perform a dynamic DNS update to the DM. There are a 523 number of issues with this. The first one is that TSIG or SIG(0) 524 make scenarios where the end user needs to interact via its web 525 browser more complex. More precisely, authorization and access 526 control granted via OAUTH would be unnecessarily complex with TSIG or 527 SIG(0). 529 The main one is that the Dynamic DNS update would also update the 530 parent zone's (NS, DS and associated A or AAAA records) while the 531 goal is to update the DM configuration files. The visible NS records 532 SHOULD remain pointing at the cloud provider's anycast addresses. 533 Revealing the address of the HNA in the DNS is not desirable. Please 534 see section Section 4.2 for more details. 536 This specification assumes: 538 o the DM serves both the Control Channel and Synchronization Channel 539 on a single IP address, single port and with a single transport 540 protocol. 542 o By default, the HNA uses a single IP address for both the Control 543 and Synchronization channel. However, the HNA MAY use distinct IP 544 addresses for the Control Channel and the Synchronization Channel 545 - see section Section 5 and section Section 4.3 for more details. 547 The Distribution Channel is internal to the DOI and as such is not 548 the primary concern of this specification. 550 4. Control Channel between Homenet Naming Authority (HNA) and 551 Distribution Master (DM) 553 The DM Control Channel is used by the HNA and the DOI to exchange 554 information related to the configuration of the delegation which 555 includes information to build the Public Homenet Zone (see 556 Section 4.1), information to build the DNSSEC chain of trust (see 557 Section 4.2) and information to set the Synchronization Channel (see 558 Section 4.3). 560 4.1. Information to build the Public Homenet Zone 562 When the HNA builds the Public Homenet Zone, it must include 563 information that it retrieves from the DM relating to how the zone is 564 to be published. 566 The information includes at least names and IP addresses of the 567 Public Authoritative Name Servers. In term of RRset information this 568 includes: 570 o the MNAME of the SOA, 572 o the NS and associated A and AAA RRsets of the name servers. 574 Optionally the DOI MAY also provide operational parameters such as 575 other fields of SOA (SERIAL, RNAME, REFRESH, RETRY, EXPIRE and 576 MINIMUM). As the information is necessary for the HNA to proceed and 577 the information is associated to the DOI, this information exchange 578 is mandatory. 580 4.2. Information to build the DNSSEC chain of trust 582 The HNA SHOULD provide the hash of the KSK (DS RRset), so the that 583 DOI provides this value to the parent zone. A common deployment use 584 case is that the DOI is the registrar of the Registered Homenet 585 Domain, and as such, its relationship with the registry of the parent 586 zone enables it to update the parent zone. When such relation 587 exists, the HNA should be able to request the DOI to update the DS 588 RRset in the parent zone. A direct update is especially necessary to 589 initialize the chain of trust. 591 Though the HNA may also later directly update the values of the DS 592 via the Control Channel, it is RECOMMENDED to use other mechanisms 593 such as CDS and CDNSKEY [RFC7344] for transparent updates during key 594 roll overs. 596 As some deployment may not provide a DOI that will be able to update 597 the DS in the parent zone, this information exchange is OPTIONAL. 599 By accepting the DS RR, the DM commits in taking care of advertising 600 the DS to the parent zone. Upon refusal, the DM clearly indicates it 601 does not have the capacity to proceed to the update. 603 4.3. Information to set the Synchronization Channel 605 The HNA works as a primary authoritative DNS server, while the DM 606 works like a secondary. As a result, the HNA MUST provide the IP 607 address the DM is using to reach the HNA. The synchronization 608 Channel will be set between that IP address and the IP address of the 609 DM. By default, the IP address used by the HNA in the Control 610 Channel is considered by the DM and the specification of the IP by 611 the HNA is only OPTIONAL. The transport channel (including port) is 612 the same as the one used between the HNA and the DM for the Control 613 Channel. 615 4.4. Deleting the delegation 617 The purpose of the previous sections were to exchange information in 618 order to set a delegation. The HNA MUST also be able to delete a 619 delegation with a specific DM. Upon an instruction of deleting the 620 delegation, the DM MUST stop serving the Public Homenet Zone. 622 4.5. Messages Exchange Description 624 There are multiple ways these information could be exchanged between 625 the HNA and the DM. This specification defines a mechanism that re- 626 use the DNS exchanges format. The intention is to reuse standard 627 libraries especially to check the format of the exchanged fields as 628 well as to minimize the additional libraries needed for the HNA. The 629 re-use of DNS exchanges achieves these goals. Note that while 630 information is provided using DNS exchanges, the exchanged 631 information is not expected to be set in any zone file, instead this 632 information is expected to be processed appropriately. 634 The Control Channel is not expected to be a long term session. After 635 a predefined timer the Control Channel is expected to be terminated. 636 The Control Channel MAY Be re-opened at any time later. 638 The provisioning process SHOULD provide a method of securing the 639 Control Channel, so that the content of messages can be 640 authenticated. This authentication MAY be based on certificates for 641 both the DM and each HNA. The DM may also create the initial 642 configuration for the delegation zone in the parent zone during the 643 provisioning process. 645 4.5.1. Retrieving information for the Public Homenet Zone. 647 The information provided by the DM to the HNA is retrieved by the HNA 648 with an AXFR exchange. The AXFR message enables the response to 649 contain any type of RRsets. The response might be extended in the 650 future if additional information will be needed. Alternatively, the 651 information provided by the HNA to the DM is pushed by the HNA via a 652 DNS update exchange [RFC2136]. 654 To retrieve the necessary information to build the Public Homenet 655 Zone, the HNA MUST send an DNS request of type AXFR associated to the 656 Registered Homenet Domain. The DM MUST respond with a zone template. 657 The zone template MUST contain a RRset of type SOA, one or multiple 658 RRset of type NS and zero or more RRset of type A or AAAA. 660 o The SOA RR is used to indicate to the HNA the value of the MNAME 661 of the Public Homenet Zone. 663 o The NAME of the SOA RR MUST be the Registered Homenet Domain. 665 o The MNAME value of the SOA RDATA is the value provided by the DOI 666 to the HNA. 668 o Other RDATA values (RNAME, REFRESH, RETRY, EXPIRE and MINIMUM) are 669 provided by the DOI as suggestions. 671 The NS RRsets are used to carry the Public Authoritative Servers of 672 the DOI. Their associated NAME MUST be the Registered Homenet 673 Domain. 675 The TTL and RDATA are those expected to be published on the Public 676 Homenet Zone. The RRsets of Type A and AAAA MUST have their NAME 677 matching the NSDNAME of one of the NS RRsets. 679 Upon receiving the response, the HNA MUST validate format and 680 properties of the SOA, NS and A or AAAA RRsets. If an error occurs, 681 the HNA MUST stop proceeding and MUST report an error. Otherwise, 682 the HNA builds the Public Homenet Zone by setting the MNAME value of 683 the SOA as indicated by the SOA provided by the AXFR response. The 684 HNA SHOULD set the value of NAME, REFRESH, RETRY, EXPIRE and MINIMUM 685 of the SOA to those provided by the AXFR response. The HNA MUST 686 insert the NS and corresponding A or AAAA RRset in its Public Homenet 687 Zone. The HNA MUST ignore other RRsets. If an error message is 688 returned by the DM, the HNA MUST proceed as a regular DNS resolution. 689 Error messages SHOULD be logged for further analysis. If the 690 resolution does not succeed, the outsourcing operation is aborted and 691 the HNA MUST close the Control Channel. 693 4.5.2. Providing information for the DNSSEC chain of trust 695 To provide the DS RRset to initialize the DNSSEC chain of trust the 696 HNA MAY send a DNS update [RFC2136] message. 698 The DNS update message is composed of a Header section, a Zone 699 section, a Pre-requisite section, and Update section and an 700 additional section. The Zone section MUST set the ZNAME to the 701 parent zone of the Registered Homenet Domain - that is where the DS 702 records should be inserted. As described [RFC2136], ZTYPE is set to 703 SOA and ZCLASS is set to the zone's class. The Pre-requisite section 704 MUST be empty. The Update section is a DS RRset with its NAME set to 705 the Registered Homenet Domain and the associated RDATA corresponds to 706 the value of the DS. The Additional Data section MUST be empty. 708 Though the pre-requisite section MAY be ignored by the DM, this value 709 is fixed to remain coherent with a standard DNS update. 711 Upon receiving the DNS update request, the DM reads the DS RRset in 712 the Update section. The DM checks ZNAME corresponds to the parent 713 zone. The DM SHOULD ignore non empty the Pre-requisite and 714 Additional Data section. The DM MAY update the TTL value before 715 updating the DS RRset in the parent zone. Upon a successful update, 716 the DM should return a NOERROR response as a commitment to update the 717 parent zone with the provided DS. An error indicates the MD does not 718 update the DS, and other method should be used by the HNA. 720 The regular DNS error message SHOULD be returned to the HNA when an 721 error occurs. In particular a FORMERR is returned when a format 722 error is found, this includes when unexpected RRSets are added or 723 when RRsets are missing. A SERVFAIL error is returned when a 724 internal error is encountered. A NOTZONE error is returned when 725 update and Zone sections are not coherent, a NOTAUTH error is 726 returned when the DM is not authoritative for the Zone section. A 727 REFUSED error is returned when the DM refuses to proceed to the 728 configuration and the requested action. 730 4.5.3. Providing information for the Synchronization Channel 732 To provide a non default IP address used by the HNA for the 733 Synchronization Channel, the HNA MAY send a DNS Update message. Such 734 exchange is OPTIONAL. 736 Similarly to the Section 4.5.2, the HNA MAY optionally specify the IP 737 address using a DNS update message. The Zone section sets its ZNAME 738 to the parent zone of the Registered Homenet Domain, ZTYPE is set to 739 SOA and ZCLASS is set to the zone's type. Pre-requisite is empty. 740 The Update section is a RRset of type NS. The Additional Data 741 section contains the RRsets of type A or AAAA that designates the IP 742 addresses associated to the primary (or the HNA). 744 The reason to provide these IP addresses is that it is NOT 745 RECOMMENDED to publish these IP addresses. As a result, it is not 746 expected to resolve them. 748 Upon receiving the DNS update request, the DM reads the IP addresses 749 and checks the ZNAME corresponds to the parent zone. The DM SHOULD 750 ignore a non empty Pre-requisite section. The DM configures the 751 secondary with the IP addresses and returns a NOERROR response to 752 indicate it is committed to serve as a secondary. 754 Similarly to Section 4.5.2, DNS errors are used and an error 755 indicates the DM is not configured as a secondary. 757 4.5.4. HNA instructing deleting the delegation 759 To instruct to delete the delegation the HNA SHOULD send a DNS UPDATE 760 Delete message. 762 The Zone section sets its ZNAME to the Registered Homenet Domain, the 763 ZTYPE to SOA and the ZCLASS to zone's type. The Pre-requisite 764 section is empty. The Update section is a RRset of type NS with the 765 NAME set to the Registered Domain Name. As indicated by [RFC2136] 766 section 2.5.2 the delete instruction is set by setting the TTL to 0, 767 the Class to ANY, the RDLENGTH to 0 and the RDATA MUST be empty. The 768 Additional Data section is empty. 770 Upon receiving the DNS update request, the DM checks the request and 771 removes the delegation. The DM returns a NOERROR response to 772 indicate the delegation has been deleted. Similarly to 773 Section 4.5.2, DNS errors are used and an error indicates the 774 delegation has not been deleted. 776 4.6. Securing the Control Channel between Homenet Naming Authority 777 (HNA) and Distribution Master (DM) 779 The control channel between the HNA and the DM MUST be secured at 780 both the HNA and the DM. 782 Secure protocols (like TLS [RFC8446] SHOULD be used to secure the 783 transactions between the DM and the HNA. 785 The advantage of TLS is that this technology is widely deployed, and 786 most of the devices already embed TLS libraries, possibly also taking 787 advantage of hardware acceleration. Further, TLS provides 788 authentication facilities and can use certificates to mutually 789 authenticate the DM and HNA at the application layer, including 790 available API. On the other hand, using TLS requires implementing 791 DNS exchanges over TLS, as well as a new service port. 793 The HNA SHOULD authenticate inbound connections from the DM using 794 standard mechanisms, such as a public certificate with baked-in root 795 certificates on the HNA, or via DANE [RFC6698]. The HNA is expected 796 to be provisioned with a connection to the DM by the manufacturer, or 797 during some user-initiated onboarding process, see Section 10. 799 The DM SHOULD authenticate the HNA and check that inbound messages 800 are from the appropriate client. The DM MAY use a self-signed CA 801 certificate mechanism per HNA, or public certificates for this 802 purpose. 804 IPsec [RFC4301] and IKEv2 [RFC7296] were considered. They would need 805 to operate in transport mode, and the authenticated end points would 806 need to be visible to the applications, and this is not commonly 807 available at the time of this writing. 809 A pure DNS solution using TSIG and/or SIG(0) to authenticate message 810 was also considered. Section 10 envisions one mechanism would 811 involve the end user, with a browser, signing up to a service 812 provider, with a resulting OAUTH2 token to be provided to the HNA. A 813 way to translate this OAUTH2 token from HTTPS web space to DNS SIG(0) 814 space seems overly problematic, and so the enrollment protocol using 815 web APIs was determined to be easier to implement at scale. 817 Note also that authentication of message exchanges between the HNA 818 and the DM SHOULD NOT use the external IP address of the HNA to index 819 the appropriate keys. As detailed in Section 11, the IP addresses of 820 the DM and the Hidden Primary are subject to change, for example 821 while the network is being renumbered. This means that the necessary 822 keys to authenticate transaction SHOULD NOT be indexed using the IP 823 address, and SHOULD be resilient to IP address changes. 825 4.7. Implementation Concerns 827 The Hidden Primary Server on the HNA differs from a regular 828 authoritative server for the home network due to: 830 Interface Binding: the Hidden Primary Server will almost certainly 831 listen on the WAN Interface, whereas a regular Homenet 832 Authoritative Servers would listen on the internal home network 833 interface. 835 Limited exchanges: the purpose of the Hidden Primary Server is to 836 synchronize with the DM, not to serve any zones to end users, or 837 the public Internet. 839 As a result, exchanges are performed with specific nodes (the DM). 840 Further, exchange types are limited. The only legitimate exchanges 841 are: NOTIFY initiated by the Hidden Primary and IXFR or AXFR 842 exchanges initiated by the DM. 844 On the other hand, regular authoritative servers would respond to any 845 hosts, and any DNS query would be processed. The HNA SHOULD filter 846 IXFR/AXFR traffic and drop traffic not initiated by the DM. The HNA 847 MUST MUST at least allow SOA lookups of the Homenet Zone. 849 5. DM Synchronization Channel between HNA and DM 851 The DM Synchronization Channel is used for communication between the 852 HNA and the DM for synchronizing the Public Homenet Zone. Note that 853 the Control Channel and the Synchronization Channel are by 854 construction different channels even though there they MAY use the 855 same IP addresse. In fact the Control Channel is set between the HNA 856 working as a client using port YYYY (a high range port) toward a 857 service provided by the DM at port XX (well known port). 859 On the other hand, the Synchronization Channel is set between the DM 860 working as a client using port ZZZZ ( a high range port) toward a 861 service a service provided by the HNA at port XX. 863 As a result, even though the same couple of IP addresses may be 864 involved the Control Channel and the Synchronization Channel are 865 always distinct channels. 867 Uploading and dynamically updating the zone file on the DM can be 868 seen as zone provisioning between the HNA (Hidden Primary) and the DM 869 (Secondary Server). This can be handled via AXFR + DNS Update. 871 This document RECOMMENDS use of a primary / secondary mechanism 872 instead of the use of DNS Update. The primary / secondary mechanism 873 is RECOMMENDED as it scales better and avoids DoS attacks. Note that 874 even when UPDATE messages are used, these messages are using a 875 distinct channel as those used to set the configuration. 877 Note that there is no standard way to distribute a DNS primary 878 between multiple devices. As a result, if multiple devices are 879 candidate for hosting the Hidden Primary, some specific mechanisms 880 should be designed so the home network only selects a single HNA for 881 the Hidden Primary. Selection mechanisms based on HNCP [RFC7788] are 882 good candidates. 884 The HNA acts as a Hidden Primary Server, which is a regular 885 authoritative DNS Server listening on the WAN interface. 887 The DM is configured as a secondary for the Registered Homenet Domain 888 Name. This secondary configuration has been previously agreed 889 between the end user and the provider of the DOI as part of either 890 the provisioning or due to receipt of DNS Update messages on the DM 891 Control Channel. 893 The Homenet Reverse Zone MAY also be updated either with DNS UPDATE 894 [RFC2136] or using a primary / secondary synchronization. 896 5.1. Securing the Synchronization Channel between HNA and DM 898 The Synchronization Channel used standard DNS request. 900 First the primary notifies the secondary that the zone must be 901 updated and eaves the secondary to proceed with the update when 902 possible/convenient. 904 Then, a NOTIFY message is sent by the primary, which is a small 905 packet that is less likely to load the secondary. 907 Finally, the AXFR [RFC1034] or IXFR [RFC1995] query performed by the 908 secondary is a small packet sent over TCP (section 4.2 [RFC5936]), 909 which mitigates reflection attacks using a forged NOTIFY. 911 The AXFR request from the DM to the HNA SHOULD be secured and the use 912 of TLS is RECOMMENDED [I-D.ietf-dprive-xfr-over-tls] 914 When using TLS, the HNA MAY authenticate inbound connections from the 915 DM using standard mechanisms, such as a public certificate with 916 baked-in root certificates on the HNA, or via DANE [RFC6698]. In 917 addition, to guarantee the DM remains the same across multiple TLS 918 session, the HNA and DM MAY implement [RFC8672]. 920 The HNA MAY apply a simple IP filter on inbound AXFR requests to 921 ensure they only arrive from the DM Synchronization Channel. In this 922 case, the HNA SHOULD regularly check (via DNS resolution) that the 923 address of the DM in the filter is still valid. 925 6. DM Distribution Channel 927 The DM Distribution Channel is used for communication between the DM 928 and the Public Authoritative Servers. The architecture and 929 communication used for the DM Distribution Channels is outside the 930 scope of this document, and there are many existing solutions 931 available e.g. rsynch, DNS AXFR, REST, DB copy. 933 7. HNA Security Policies 935 This section details security policies related to the Hidden Primary 936 / Secondary synchronization. 938 The HNA, as Hidden Primary SHOULD drop any queries from the home 939 network. This could be implemented via port binding and/or firewall 940 rules. The precise mechanism deployed is out of scope of this 941 document. The Hidden Primary SHOULD drop any DNS queries arriving on 942 the WAN interface that are not issued from the DM. The Hidden 943 Primary SHOULD drop any outgoing packets other than DNS NOTIFY query, 944 SOA response, IXFR response or AXFR responses. The Hidden Primary 945 SHOULD drop any incoming packets other than DNS NOTIFY response, SOA 946 query, IXFR query or AXFR query. The Hidden Primary SHOULD drop any 947 non protected IXFR or AXFR exchange,depending on how the 948 synchronization is secured. 950 8. DNSSEC compliant Homenet Architecture 952 [RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on both 953 the authoritative server and the resolver. The resolver side is out 954 of scope of this document, and only the authoritative part of the 955 server is considered. 957 This document assumes the HNA signs the Public Homenet Zone. 959 Secure delegation is achieved only if the DS RRset is properly set in 960 the parent zone. Secure delegation is performed by the HNA or the 961 DOIs. 963 The DS RRset can be updated manually with nsupdate for example. This 964 requires the HNA or the DOI to be authenticated by the DNS server 965 hosting the parent of the Public Homenet Zone. Such a trust channel 966 between the HNA and the parent DNS server may be hard to maintain 967 with HNAs, and thus may be easier to establish with the DOI. In 968 fact, the Public Authoritative Server(s) may use Automating DNSSEC 969 Delegation Trust Maintenance [RFC7344]. 971 9. Homenet Reverse Zone Channels Configuration 973 The Public Homenet Zone is associated to a Registered Homenet Domain 974 and the ownership of that domain requires a specific registration 975 from the end user as well as the HNA being provisioned with some 976 authentication credentials. Such steps are mandatory unless the DOI 977 has some other means to authenticate the HNA. Such situation may 978 occur, for example, when the ISP provides the Homenet Domain as well 979 as the DOI. 981 In this case, the HNA may be authenticated by the physical link 982 layer, in which case the authentication of the HNA may be performed 983 without additional provisioning of the HNA. While this may not be so 984 common for the Public Homenet Zone, this situation is expected to be 985 quite common for the Reverse Homenet Zone. 987 More specifically, a common case is that the upstream ISP provides 988 the IPv6 prefix to the Homenet with a IA_PD [RFC8415] option and 989 manages the DOI of the associated reverse zone. 991 This leave place for setting up automatically the relation between 992 HNA and the DNS Outsourcing infrastructure as described in 993 [I-D.ietf-homenet-naming-architecture-dhc-options]. 995 In the case of the reverse zone, the DOI authenticates the source of 996 the updates by IPv6 Access Control Lists. In the case of the reverse 997 zone, the ISP knows exactly what addresses have been delegated. The 998 HNA SHOULD therefore always originate Synchronization Channel updates 999 from an IP address within the zone that is being updated. 1001 For example, if the ISP has assigned 2001:db8:f00d::2/64 to the WAN 1002 interface (by DHCPv6, or PPP/RA), then the HNA should originate 1003 Synchronization Channel updates from 2001:db8:f00d::2. 1005 An ISP that has delegated 2001:db8:babe::/56 to the HNA via 1006 DHCPv6-PD, then HNA should originate Synchronization Channel updates 1007 an IP within that subnet, such as 2001:db8:babe:0001::2. 1009 With this relation automatically configured, the synchronization 1010 between the Home network and the DOI happens similarly as for the 1011 Public Homenet Zone described earlier in this document. 1013 Note that for home networks hosted by multiple ISPs, each ISP 1014 provides only the DOI of the reverse zones associated to the 1015 delegated prefix. It is also likely that the DNS exchanges will need 1016 to be performed on dedicated interfaces as to be accepted by the ISP. 1017 More specifically, the reverse zone associated to prefix 1 will not 1018 be possible to be performs by the HNA using an IP address that 1019 belongs to prefix 2. Such constraints does not raise major concerns 1020 either for hot standby or load sharing configuration. 1022 With IPv6, the domain space for IP addresses is so large that reverse 1023 zone may be confronted with scalability issues. How the reverse zone 1024 is generated is out of scope of this document. 1025 [I-D.howard-dnsop-ip6rdns] provides guidance on how to address 1026 scalability issues. 1028 10. Homenet Public Zone Channel Configurations 1030 This document does not deal with how the HNA is provisioned with a 1031 trusted relationship to the Distribution Master for the forward zone. 1033 This section details what needs to be provisioned into the HNA and 1034 serves as a requirements statement for mechanisms. 1036 The HNA needs to be provisioned with: 1038 o the Registered Domain (e.g., myhome.isp.example ) 1040 o the contact info for the Distribution Master (DM), including the 1041 DNS name (FQDN), possibly including the IP literal, and a 1042 certificate (or anchor) to be used to authenticate the service 1044 o the DM transport protocol and port (the default is DNS over TLS, 1045 on port 853) 1047 o the HNA credentials used by the DM for its authentication. 1049 The HNA will need to select an IP address for communication for the 1050 Synchronization Channel. This is typically the outside WAN address 1051 of the router, but could be an IPv6 LAN address in the case of a home 1052 with multiple ISPs (and multiple border routers). This is 1053 communicated in section Section 4.5.3 when the NS and A or AAAA 1054 RRsets are communicated. 1056 The above parameters MUST be be provisioned for ISP-specific reverse 1057 zones, as per [I-D.ietf-homenet-naming-architecture-dhc-options]. 1058 ISP-specific forward zones MAY also be provisioned using 1059 [I-D.ietf-homenet-naming-architecture-dhc-options], but zones which 1060 are not related to a specific ISP zone (such as with a DNS provider) 1061 must be provisioned through other means. 1063 Similarly, if the HNA is provided by a registrar, the HNA may be 1064 given configured to end user. 1066 In the absence of specific pre-established relation, these pieces of 1067 information may be entered manually by the end user. In order to 1068 ease the configuration from the end user the following scheme may be 1069 implemented. 1071 The HNA may present the end user a web interface where it provides 1072 the end user the ability to indicate the Registered Homenet Domain or 1073 the registrar for example a preselected list. Once the registrar has 1074 been selected, the HNA redirects the end user to that registrar in 1075 order to receive a access token. The access token will enable the 1076 HNA to retrieve the DM parameters associated to the Registered 1077 Domain. These parameters will include the credentials used by the 1078 HNA to establish the Control and Synchronization Channels. 1080 Such architecture limits the necessary steps to configure the HNA 1081 from the end user. 1083 11. Renumbering 1085 This section details how renumbering is handled by the Hidden Primary 1086 server or the DM. Both types of renumbering are discussed i.e. 1087 "make-before-break" and "break-before-make" (aka flash renumbering). 1089 In the make-before-break renumbering scenario, the new prefix is 1090 advertised, the network is configured to prepare the transition to 1091 the new prefix. During a period of time, the two prefixes old and 1092 new coexist, before the old prefix is completely removed. 1094 In the break-before-make renumbering scenario, the new prefix is 1095 advertised making the old prefix obsolete. 1097 Renumbering has been extensively described in [RFC4192] and analyzed 1098 in [RFC7010] and the reader is expected to be familiar with them 1099 before reading this section. 1101 11.1. Hidden Primary 1103 In a renumbering scenario, the HNA or Hidden Primary is informed it 1104 is being renumbered. In most cases, this occurs because the whole 1105 home network is being renumbered. As a result, the Public Homenet 1106 Zone will also be updated. Although the new and old IP addresses may 1107 be stored in the Public Homenet Zone, we recommend that only the 1108 newly reachable IP addresses be published. 1110 To avoid reachability disruption, IP connectivity information 1111 provided by the DNS SHOULD be coherent with the IP plane. In our 1112 case, this means the old IP address SHOULD NOT be provided via the 1113 DNS when it is not reachable anymore. Let for example TTL be the TTL 1114 associated with a RRset of the Public Homenet Zone, it may be cached 1115 for TTL seconds. Let T_NEW be the time the new IP address replaces 1116 the old IP address in the Homenet Zone, and T_OLD_UNREACHABLE the 1117 time the old IP is not reachable anymore. 1119 In the case of the make-before-break, seamless reachability is 1120 provided as long as T_OLD_UNREACHABLE - T_NEW > 2 * TTL. If this is 1121 not satisfied, then devices associated with the old IP address in the 1122 home network may become unreachable for 2 * TTL - (T_OLD_UNREACHABLE 1123 - T_NEW). In the case of a break-before-make, T_OLD_UNREACHABLE = 1124 T_NEW, and the device may become unreachable up to 2 * TTL. Of 1125 course if T_NEW >= T_OLD_UNREACHABLE, the disruption is increased. 1127 Once the Public Homenet Zone file has been updated on the Hidden 1128 Primary, the Hidden Primary needs to inform the DOI that the Public 1129 Homenet Zone has been updated and that the IP address to use to 1130 retrieve the updated zone has also been updated. Both notifications 1131 are performed using regular DNS exchanges. Mechanisms to update an 1132 IP address provided by lower layers with protocols like SCTP 1133 [RFC4960], MOBIKE [RFC4555] are not considered in this document. 1134 Instead the IP address of the HNA is updated using the 1135 Synchronization Channel as described in Section 4.3. 1137 12. Privacy Considerations 1139 Outsourcing the DNS Authoritative service from the HNA to a third 1140 party raises a few privacy related concerns. 1142 The Public Homenet Zone lists the names of services hosted in the 1143 home network. Combined with blocking of AXFR queries, the use of 1144 NSEC3 [RFC5155] (vs NSEC [RFC4034]) prevents an attacker from being 1145 able to walk the zone, to discover all the names. However, the 1146 attacker may be able to walk the reverse DNS zone, or use other 1147 reconnaissance techniques to learn this information as described in 1148 [RFC7707]. 1150 In general a home network owner is expected to publish only names for 1151 which there is some need to be able to reference externally. 1152 Publication of the name does not imply that the service is 1153 necessarily reachable from any or all parts of the Internet. 1154 [RFC7084] mandates that the outgoing-only policy [RFC6092] be 1155 available, and in many cases it is configured by default. A well 1156 designed User Interface would combine a policy for making a service 1157 public by a name with a policy on who may access it. 1159 In many cases, the home network owner wishes to publish names for 1160 services that only they will be able to access. The access control 1161 may consist of an IP source address range, or access may be 1162 restricted via some VPN functionality. The purpose of publishing the 1163 name is so that the service may be access by the same name both 1164 within the home, and outside the home. Sending traffic to the 1165 relevant IPv6 address causes the relevant VPN policy to be enacted 1166 upon. 1168 While the problem of getting access to internal names has been solved 1169 in Enterprise configurations with a split-DNS, and such a thing could 1170 be done in the home, many recent improvements to VPN user interfaces 1171 make it more likely that an individual might have multiple 1172 connections configured. For instance, an adult child checking on the 1173 state of a home automation system for a parent. 1175 In addition to the Public Homenet Zone, pervasive DNS monitoring can 1176 also monitor the traffic associated with the Public Homenet Zone. 1177 This traffic may provide an indication of the services an end user 1178 accesses, plus how and when they use these services. Although, 1179 caching may obfuscate this information inside the home network, it is 1180 likely that outside your home network this information will not be 1181 cached. 1183 13. Security Considerations 1185 This document exposes a mechanism that prevents the HNA from being 1186 exposed to the Internet and served DNS request from the Internet. 1187 These requests are instead served by the DOI. While this limits the 1188 level of exposure of the HNA, the HNA remains exposed to the Internet 1189 with communications with the DOI. This section analyses the attack 1190 surface associated to these communications. In addition, the DOI 1191 exposes data that are related to the home network. This section also 1192 analyses the implication of such exposure. 1194 13.1. HNA DM channels 1196 The channels between HNA and DM are mutually authenticated and 1197 encrypted with TLS [RFC8446] and its associated security 1198 considerations apply. To ensure the multiple TLS session are are 1199 continuously authenticating the same entity, TLS may take advantage 1200 of second factor authentication as described in [RFC8672]. 1202 At the time of writing TLS 1.2 or TLS 1.3 can be used and TLS 1.3 (or 1203 newer) SHOULD be supported. 1205 The DNS protocol is subject to reflection attacks, however, these 1206 attacks are largely applicable when DNS is carried over UDP. The 1207 interfaces between the HNA and DM are using TLS over TCP, which 1208 prevents such reflection attacks. Note that Public Authoritative 1209 servers hosted by the DOI are subject to such attacks, but that is 1210 out of scope of our document. 1212 Note that in the case of the Reverse Homenet Zone, the data is less 1213 subject to attacks than in the Public Homenet Zone. In addition, the 1214 DM and RDM may be provided by the ISP - as described in 1215 [I-D.ietf-homenet-naming-architecture-dhc-options], in which case DM 1216 and RDM might be less exposed to attacks - as communications within a 1217 network. 1219 13.2. Names are less secure than IP addresses 1221 This document describes how an end user can make their services and 1222 devices from his home network reachable on the Internet by using 1223 names rather than IP addresses. This exposes the home network to 1224 attackers, since names are expected to include less entropy than IP 1225 addresses. In fact, with IP addresses, the Interface Identifier is 1226 64 bits long leading to up to 2^64 possibilities for a given 1227 subnetwork. This is not to mention that the subnet prefix is also of 1228 64 bits long, thus providing up to 2^64 possibilities. On the other 1229 hand, names used either for the home network domain or for the 1230 devices present less entropy (livebox, router, printer, nicolas, 1231 jennifer, ...) and thus potentially exposes the devices to dictionary 1232 attacks. 1234 13.3. Names are less volatile than IP addresses 1236 IP addresses may be used to locate a device, a host or a service. 1237 However, home networks are not expected to be assigned a time 1238 invariant prefix by ISPs. As a result, observing IP addresses only 1239 provides some ephemeral information about who is accessing the 1240 service. On the other hand, names are not expected to be as volatile 1241 as IP addresses. As a result, logging names over time may be more 1242 valuable than logging IP addresses, especially to profile an end 1243 user's characteristics. 1245 PTR provides a way to bind an IP address to a name. In that sense, 1246 responding to PTR DNS queries may affect the end user's privacy. For 1247 that reason end users may choose not to respond to PTR DNS queries 1248 and MAY instead return a NXDOMAIN response. 1250 14. Information Model for Outsourced information 1252 This section is non-normative for the front-end protocol. It 1253 specifies an optional format for the set of parameters required by 1254 the HNA to configure the naming architecture of this document. 1256 In cases where a home router has not been provisioned by the 1257 manufacturer (when forward zones are provided by the manufacturer), 1258 or by the ISP (when the ISP provides this service), then a home user/ 1259 owner will need to configure these settings via an administrative 1260 interface. 1262 By defining a standard format (in JSON) for this configuration 1263 information, the user/owner may be able to just copy and paste a 1264 configuration blob from the service provider into the administrative 1265 interface of the HNA. 1267 This format may also provide the basis for a future OAUTH2 [RFC6749] 1268 flow that could do the setup automatically. 1270 The HNA needs to be configured with the following parameters as 1271 described by this CDDL [RFC8610]. These are the parameters are 1272 necessary to establish a secure channel between the HNA and the DM as 1273 well as to specify the DNS zone that is in the scope of the 1274 communication. 1276 hna-configuration = { 1277 "registered_domain" : tstr, 1278 "dm" : tstr, 1279 ? "dm_transport" : "DoT" 1280 ? "dm_port" : uint, 1281 ? "dm_acl" : hna-acl / [ +hna-acl ] 1282 ? "hna_auth_method": hna-auth-method 1283 ? "hna_certificate": tstr 1284 } 1286 hna-acl = tstr 1287 hna-auth-method /= "certificate" 1289 For example: 1291 { 1292 "registered_domain" : "n8d234f.r.example.net", 1293 "dm" : "2001:db8:1234:111:222::2", 1294 "dm_transport" : "DoT", 1295 "dm_port" : 4433, 1296 "dm_acl" : "2001:db8:1f15:62e:21c::/64" 1297 or [ "2001:db8:1f15:62e:21c::/64", ... ] 1298 "hna_auth_method" : "certificate", 1299 "hna_certificate" : "-----BEGIN CERTIFICATE-----\nMIIDTjCCFGy....", 1300 } 1302 14.1. Outsourced Information Model 1304 Registered Homenet Domain (zone) The Domain Name of the zone. 1305 Multiple Registered Homenet Domains may be provided. This will 1306 generate the creation of multiple Public Homenet Zones. This 1307 parameter is MANDATORY. 1309 Distribution Master notification address (dm) The associated FQDNs 1310 or IP addresses of the DM to which DNS notifies should be sent. 1311 This parameter is MANDATORY. IP addresses are optional and the 1312 FQDN is sufficient and preferred. If there are concerns about the 1313 security of the name to IP translation, then DNSSEC should be 1314 employed. 1316 As the session between the HNA and the DM is authenticated with TLS, 1317 the use of names is easier. 1319 As certificates are more commonly emitted for FQDN than for IP 1320 addresses, it is preferred to use names and authenticate the name of 1321 the DM during the TLS session establishment. 1323 Supported Transport (dm_transport) The transport that carries the 1324 DNS exchanges between the HNA and the DM. Typical value is "DoT" 1325 but it may be extended in the future with "DoH", "DoQ" for 1326 example. This parameter is OPTIONAL and by default the HNA uses 1327 DoT. 1329 Distribution Master Port (dm_port) Indicates the port used by the 1330 DM. This parameter is OPTIONAL and the default value is provided 1331 by the Supported Transport. In the future, additional transport 1332 may not have default port, in which case either a default port 1333 needs to be defined or this parameter become MANDATORY. 1335 Note that HNA does not defines ports for the Synchronization Channel. 1336 In any case, this is not expected to part of the configuration, but 1337 instead negotiated through the Configuration Channel. Currently the 1338 Configuration Channel does not provide this, and limits its agility 1339 to a dedicated IP address. If such agility is needed in the future, 1340 additional exchanges will need to be defined. 1342 Authentication Method ("hna_auth_method"): How the HNA authenticates 1343 itself to the DM within the TLS connection(s). The authentication 1344 meth of can typically be "certificate", "psk" or "none". This 1345 Parameter is OPTIONAL and by default the Authentication Method is 1346 "certificate". 1348 Authentication data ("hna_certificate", "hna_key"): : The certificate 1349 chain used to authenticate the HNA. This parameter is OPTIONAL and 1350 when not specified, a self-signed certificate is used. 1352 Distribution Master AXFR permission netmask (dm_acl): The subnet 1353 from which the CPE should accept SOA queries and AXFR requests. A 1354 subnet is used in the case where the DNS Outsourced Infrastructure 1355 consists of a number of different systems. An array of addresses 1356 is permitted. This parameter is OPTIONAL and if unspecified, the 1357 CPE the IP addresses specified in the dm_notify parameters or the 1358 IP addresses that result from the DNS(SEC) resolution when 1359 dm_notify specifies a FQDN. 1361 For forward zones, the relationship between the HNA and the forward 1362 zone provider may be the result of a number of transactions: 1364 1. The forward zone outsourcing may be provided by the maker of the 1365 Homenet router. In this case, the identity and authorization 1366 could be built in the device at manufacturer provisioning time. 1367 The device would need to be provisioned with a device-unique 1368 credential, and it is likely that the Registered Homenet Domain 1369 would be derived from a public attribute of the device, such as a 1370 serial number (see Appendix B or 1371 [I-D.richardson-homerouter-provisioning] for more details ). 1373 2. The forward zone outsourcing may be provided by the Internet 1374 Service Provider. In this case, the use of 1375 [I-D.ietf-homenet-naming-architecture-dhc-options] to provide the 1376 credentials is appropriate. 1378 3. The forward zone may be outsourced to a third party, such as a 1379 domain registrar. In this case, the use of the JSON-serialized 1380 YANG data model described in this section is appropriate, as it 1381 can easily be copy and pasted by the user, or downloaded as part 1382 of a web transaction. 1384 For reverse zones, the relationship is always with the upstream ISP 1385 (although there may be more than one), and so 1386 [I-D.ietf-homenet-naming-architecture-dhc-options] is always the 1387 appropriate interface. 1389 The following is an abbridged example of a set of data that 1390 represents the needed configuration parameters for outsourcing. 1392 15. IANA Considerations 1394 This document has no actions for IANA. 1396 16. Acknowledgment 1398 The authors wish to thank Philippe Lemordant for its contributions on 1399 the early versions of the draft; Ole Troan for pointing out issues 1400 with the IPv6 routed home concept and placing the scope of this 1401 document in a wider picture; Mark Townsley for encouragement and 1402 injecting a healthy debate on the merits of the idea; Ulrik de Bie 1403 for providing alternative solutions; Paul Mockapetris, Christian 1404 Jacquenet, Francis Dupont and Ludovic Eschard for their remarks on 1405 HNA and low power devices; Olafur Gudmundsson for clarifying DNSSEC 1406 capabilities of small devices; Simon Kelley for its feedback as 1407 dnsmasq implementer; Andrew Sullivan, Mark Andrew, Ted Lemon, Mikael 1408 Abrahamson, and Ray Bellis for their feedback on handling different 1409 views as well as clarifying the impact of outsourcing the zone 1410 signing operation outside the HNA; Mark Andrew and Peter Koch for 1411 clarifying the renumbering. 1413 17. Contributors 1415 The co-authors would like to thank Chris Griffiths and Wouter 1416 Cloetens that provided a significant contribution in the early 1417 versions of the document. 1419 18. References 1421 18.1. Normative References 1423 [I-D.ietf-dprive-xfr-over-tls] 1424 Toorop, W., Dickinson, S., Sahib, S., Aras, P., and A. 1425 Mankin, "DNS Zone Transfer-over-TLS", draft-ietf-dprive- 1426 xfr-over-tls-11 (work in progress), April 2021. 1428 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1429 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1430 . 1432 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 1433 DOI 10.17487/RFC1995, August 1996, 1434 . 1436 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1437 Requirement Levels", BCP 14, RFC 2119, 1438 DOI 10.17487/RFC2119, March 1997, 1439 . 1441 [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, 1442 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 1443 RFC 2136, DOI 10.17487/RFC2136, April 1997, 1444 . 1446 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1447 Rose, "Resource Records for the DNS Security Extensions", 1448 RFC 4034, DOI 10.17487/RFC4034, March 2005, 1449 . 1451 [RFC4192] Baker, F., Lear, E., and R. Droms, "Procedures for 1452 Renumbering an IPv6 Network without a Flag Day", RFC 4192, 1453 DOI 10.17487/RFC4192, September 2005, 1454 . 1456 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1457 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 1458 December 2005, . 1460 [RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol 1461 (MOBIKE)", RFC 4555, DOI 10.17487/RFC4555, June 2006, 1462 . 1464 [RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol", 1465 RFC 4960, DOI 10.17487/RFC4960, September 2007, 1466 . 1468 [RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS 1469 Security (DNSSEC) Hashed Authenticated Denial of 1470 Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008, 1471 . 1473 [RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol 1474 (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010, 1475 . 1477 [RFC6092] Woodyatt, J., Ed., "Recommended Simple Security 1478 Capabilities in Customer Premises Equipment (CPE) for 1479 Providing Residential IPv6 Internet Service", RFC 6092, 1480 DOI 10.17487/RFC6092, January 2011, 1481 . 1483 [RFC6644] Evans, D., Droms, R., and S. Jiang, "Rebind Capability in 1484 DHCPv6 Reconfigure Messages", RFC 6644, 1485 DOI 10.17487/RFC6644, July 2012, 1486 . 1488 [RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication 1489 of Named Entities (DANE) Transport Layer Security (TLS) 1490 Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August 1491 2012, . 1493 [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, 1494 DOI 10.17487/RFC6762, February 2013, 1495 . 1497 [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service 1498 Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, 1499 . 1501 [RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and 1502 P. Selkirk, "Port Control Protocol (PCP)", RFC 6887, 1503 DOI 10.17487/RFC6887, April 2013, 1504 . 1506 [RFC7010] Liu, B., Jiang, S., Carpenter, B., Venaas, S., and W. 1507 George, "IPv6 Site Renumbering Gap Analysis", RFC 7010, 1508 DOI 10.17487/RFC7010, September 2013, 1509 . 1511 [RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1512 Requirements for IPv6 Customer Edge Routers", RFC 7084, 1513 DOI 10.17487/RFC7084, November 2013, 1514 . 1516 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 1517 Kivinen, "Internet Key Exchange Protocol Version 2 1518 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 1519 2014, . 1521 [RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating 1522 DNSSEC Delegation Trust Maintenance", RFC 7344, 1523 DOI 10.17487/RFC7344, September 2014, 1524 . 1526 [RFC7368] Chown, T., Ed., Arkko, J., Brandt, A., Troan, O., and J. 1527 Weil, "IPv6 Home Networking Architecture Principles", 1528 RFC 7368, DOI 10.17487/RFC7368, October 2014, 1529 . 1531 [RFC7558] Lynn, K., Cheshire, S., Blanchet, M., and D. Migault, 1532 "Requirements for Scalable DNS-Based Service Discovery 1533 (DNS-SD) / Multicast DNS (mDNS) Extensions", RFC 7558, 1534 DOI 10.17487/RFC7558, July 2015, 1535 . 1537 [RFC7707] Gont, F. and T. Chown, "Network Reconnaissance in IPv6 1538 Networks", RFC 7707, DOI 10.17487/RFC7707, March 2016, 1539 . 1541 [RFC7788] Stenberg, M., Barth, S., and P. Pfister, "Home Networking 1542 Control Protocol", RFC 7788, DOI 10.17487/RFC7788, April 1543 2016, . 1545 [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., 1546 and P. Hoffman, "Specification for DNS over Transport 1547 Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 1548 2016, . 1550 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1551 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1552 May 2017, . 1554 [RFC8375] Pfister, P. and T. Lemon, "Special-Use Domain 1555 'home.arpa.'", RFC 8375, DOI 10.17487/RFC8375, May 2018, 1556 . 1558 [RFC8415] Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A., 1559 Richardson, M., Jiang, S., Lemon, T., and T. Winters, 1560 "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", 1561 RFC 8415, DOI 10.17487/RFC8415, November 2018, 1562 . 1564 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol 1565 Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, 1566 . 1568 [RFC8555] Barnes, R., Hoffman-Andrews, J., McCarney, D., and J. 1569 Kasten, "Automatic Certificate Management Environment 1570 (ACME)", RFC 8555, DOI 10.17487/RFC8555, March 2019, 1571 . 1573 18.2. Informative References 1575 [I-D.howard-dnsop-ip6rdns] 1576 Howard, L., "Reverse DNS in IPv6 for Internet Service 1577 Providers", draft-howard-dnsop-ip6rdns-00 (work in 1578 progress), June 2014. 1580 [I-D.ietf-dprive-dnsoquic] 1581 Huitema, C., Mankin, A., and S. Dickinson, "Specification 1582 of DNS over Dedicated QUIC Connections", draft-ietf- 1583 dprive-dnsoquic-02 (work in progress), February 2021. 1585 [I-D.ietf-homenet-naming-architecture-dhc-options] 1586 Migault, D., Weber, R., Mrugalski, T., Griffiths, C., and 1587 W. Cloetens, "DHCPv6 Options for Home Network Naming 1588 Authority", draft-ietf-homenet-naming-architecture-dhc- 1589 options-11 (work in progress), April 2021. 1591 [I-D.ietf-homenet-simple-naming] 1592 Lemon, T., Migault, D., and S. Cheshire, "Homenet Naming 1593 and Service Discovery Architecture", draft-ietf-homenet- 1594 simple-naming-03 (work in progress), October 2018. 1596 [I-D.richardson-homerouter-provisioning] 1597 Richardson, M., "Provisioning Initial Device Identifiers 1598 into Home Routers", draft-richardson-homerouter- 1599 provisioning-00 (work in progress), November 2020. 1601 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 1602 Wellington, "Secret Key Transaction Authentication for DNS 1603 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 1604 . 1606 [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures 1607 ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September 1608 2000, . 1610 [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", 1611 RFC 6749, DOI 10.17487/RFC6749, October 2012, 1612 . 1614 [RFC8094] Reddy, T., Wing, D., and P. Patil, "DNS over Datagram 1615 Transport Layer Security (DTLS)", RFC 8094, 1616 DOI 10.17487/RFC8094, February 2017, 1617 . 1619 [RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS 1620 (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, 1621 . 1623 [RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data 1624 Definition Language (CDDL): A Notational Convention to 1625 Express Concise Binary Object Representation (CBOR) and 1626 JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610, 1627 June 2019, . 1629 [RFC8672] Sheffer, Y. and D. Migault, "TLS Server Identity Pinning 1630 with Tickets", RFC 8672, DOI 10.17487/RFC8672, October 1631 2019, . 1633 Appendix A. Envisioned deployment scenarios 1635 A number of deployment have been envisioned, this section aims at 1636 providing a brief description. The use cases are not limitations and 1637 this section is not normative. 1639 A.1. CPE Vendor 1641 A specific vendor with specific relations with a registrar or a 1642 registry may sell a CPE that is provisioned with provisioned domain 1643 name. Such domain name does not need to be necessary human readable. 1645 One possible way is that the vendor also provisions the HNA with a 1646 private and public keys as well as a certificate. Note that these 1647 keys are not expected to be used for DNSSEC signing. Instead these 1648 keys are solely used by the HNA to proceed to the authentication. 1649 Normally the keys should be necessary and sufficient to proceed to 1650 the authentication. The reason to combine the domain name and the 1651 key is that DOI are likely handle names better than keys and that 1652 domain names might be used as a login which enables the key to be 1653 regenerated. 1655 When the home network owner plugs the CPE at home, the relation 1656 between HNA and DM is expected to work out-of-the-box. 1658 A.2. Agnostic CPE 1660 An CPE that is not preconfigured may also take advantage to the 1661 protocol defined in this document but some configuration steps will 1662 be needed. 1664 1. The owner of the home network buys a domain name to a registrar, 1665 and as such creates an account on that registrar 1667 2. Either the registrar is also providing the outsourcing 1668 infrastructure or the home network needs to create a specific 1669 account on the outsourcing infrastructure. * If the DOI is the 1670 registrar, it has by design a proof of ownership of the domain 1671 name by the homenet owner. In this case, it is expected the DOI 1672 provides the necessary parameters to the home network owner to 1673 configure the HNA. A good way to provide the parameters would be 1674 the home network be able to copy/paste a JSON object - see 1675 Section 14. What matters at that point is the DOI being able to 1676 generate authentication credentials for the HNA to authenticate 1677 itself to the DOI. This obviously requires the home network to 1678 provide the public key generated by the HNA in a CSR. 1680 o If the DOI is not the registrar, then the proof of ownership needs 1681 to be established using protocols like ACME [RFC8555] for example 1682 that will end in the generation of a certificate. ACME is used 1683 here to the purpose of automating the generation of the 1684 certificate, the CA may be a specific CA or the DOI. With that 1685 being done, the DOI has a roof of ownership and can proceed as 1686 above. 1688 Appendix B. Example: A manufacturer provisioned HNA product flow 1690 This scenario is one where a homenet router device manufacturer 1691 decides to offer DNS hosting as a value add. 1693 [I-D.richardson-homerouter-provisioning] describes a process for a 1694 home router credential provisioning system. The outline of it is 1695 that near the end of the manufacturing process, as part of the 1696 firmware loading, the manufacturer provisions a private key and 1697 certificate into the device. 1699 In addition to having a assymmetric credential known to the 1700 manufacturer, the device also has been provisioned with an agreed 1701 upon name. In the example in the above document, the name 1702 "n8d234f.r.example.net" has already been allocated and confirmed with 1703 the manufacturer. 1705 The HNA can use the above domain for itself. It is not very pretty 1706 or personal, but if the owner wishes a better name, they can arrange 1707 for it. 1709 The configuration would look like: 1711 { 1712 "dm_notify" : "2001:db8:1234:111:222::2", 1713 "dm_acl" : "2001:db8:1234:111:222::/64", 1714 "dm_ctrl" : "manufacturer.example.net", 1715 "dm_port" : "4433", 1716 "ns_list" : [ "ns1.publicdns.example", "ns2.publicdns.example"], 1717 "zone" : "n8d234f.r.example.net", 1718 "auth_method" : "certificate", 1719 "hna_certificate":"-----BEGIN CERTIFICATE-----\nMIIDTjCCFGy....", 1720 } 1722 The dm_ctrl and dm_port values would be built into the firmware. 1724 Authors' Addresses 1726 Daniel Migault 1727 Ericsson 1728 8275 Trans Canada Route 1729 Saint Laurent, QC 4S 0B6 1730 Canada 1732 EMail: daniel.migault@ericsson.com 1734 Ralf Weber 1735 Nominum 1736 2000 Seaport Blvd 1737 Redwood City 94063 1738 US 1740 EMail: ralf.weber@nominum.com 1742 Michael Richardson 1743 Sandelman Software Works 1744 470 Dawson Avenue 1745 Ottawa, ON K1Z 5V7 1746 Canada 1748 EMail: mcr+ietf@sandelman.ca 1750 Ray Hunter 1751 Globis Consulting BV 1752 Weegschaalstraat 3 1753 Eindhoven 5632CW 1754 NL 1756 EMail: v6ops@globis.net