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Server hosts...' -- The document date (July 05, 2013) is 3945 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 2845 (Obsoleted by RFC 8945) ** Obsolete normative reference: RFC 5246 (Obsoleted by RFC 8446) ** Obsolete normative reference: RFC 5996 (Obsoleted by RFC 7296) ** Obsolete normative reference: RFC 6347 (Obsoleted by RFC 9147) Summary: 4 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 HOMENET D. Migault (Ed) 3 Internet-Draft Francetelecom - Orange 4 Intended status: Standards Track W. Cloetens 5 Expires: January 06, 2014 SoftAtHome 6 C. Griffiths 7 Dyn 8 R. Weber 9 Nominum 10 July 05, 2013 12 IPv6 Home Network Naming Delegation 13 draft-mglt-homenet-front-end-naming-delegation-02.txt 15 Abstract 17 CPEs are designed to provide IP connectivity to home networks. Most 18 CPEs assigns IP addresses to the nodes of the home network which 19 makes it a good candidate for hosting the naming service. With IPv6, 20 the naming service makes nodes reachable from the home network as 21 well as from the Internet. 23 However, CPEs have not been designed to host such a naming service. 24 More specifically, CPE have been designed neither to host a service 25 exposed on the Internet, nor to support heavy operations like zone 26 signing. Both MAY expose the CPEs to resource exhaustion which would 27 make the home network unreachable, and most probably would also 28 affect the home network inner communications. 30 In addition, DNSSEC management and configuration may not be well 31 understood or mastered by regular end users. Misconfiguration MAY 32 also results in naming service disruption, thus these end users MAY 33 prefer to rely on third party naming providers. 35 This document describes a homenet naming architecture where the CPEs 36 manage the DNS zone associates to its home network, and outsource 37 both DNSSEC management and naming service on the Internet to a third 38 party designated as the Public Authoritative Servers. 40 Status of This Memo 42 This Internet-Draft is submitted in full conformance with the 43 provisions of BCP 78 and BCP 79. 45 Internet-Drafts are working documents of the Internet Engineering 46 Task Force (IETF). Note that other groups may also distribute 47 working documents as Internet-Drafts. The list of current Internet- 48 Drafts is at http://datatracker.ietf.org/drafts/current/. 50 Internet-Drafts are draft documents valid for a maximum of six months 51 and may be updated, replaced, or obsoleted by other documents at any 52 time. It is inappropriate to use Internet-Drafts as reference 53 material or to cite them other than as "work in progress." 55 This Internet-Draft will expire on January 06, 2014. 57 Copyright Notice 59 Copyright (c) 2013 IETF Trust and the persons identified as the 60 document authors. All rights reserved. 62 This document is subject to BCP 78 and the IETF Trust's Legal 63 Provisions Relating to IETF Documents 64 (http://trustee.ietf.org/license-info) in effect on the date of 65 publication of this document. Please review these documents 66 carefully, as they describe your rights and restrictions with respect 67 to this document. Code Components extracted from this document must 68 include Simplified BSD License text as described in Section 4.e of 69 the Trust Legal Provisions and are provided without warranty as 70 described in the Simplified BSD License. 72 Table of Contents 74 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 2 75 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 76 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 77 4. Architecture Overview . . . . . . . . . . . . . . . . . . . . 5 78 5. Architecture Description . . . . . . . . . . . . . . . . . . 7 79 5.1. CPE and Public Authoritative Servers Synchronization . . 7 80 5.1.1. Synchronization with a Hidden Master . . . . . . . . 7 81 5.1.2. Securing Synchronization . . . . . . . . . . . . . . 8 82 5.2. DNS Homenet Zone configuration . . . . . . . . . . . . . 9 83 5.3. DNSSEC outsourcing configuration . . . . . . . . . . . . 10 84 5.4. CPE Security Policies . . . . . . . . . . . . . . . . . . 11 85 6. Homenet Naming Configuration . . . . . . . . . . . . . . . . 11 86 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 87 7.1. Names are less secure than IP addresses . . . . . . . . . 13 88 7.2. Names are less volatile than IP addresses . . . . . . . . 13 89 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 90 9. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 13 91 10. Normative References . . . . . . . . . . . . . . . . . . . . 14 92 Appendix A. Document Change Log . . . . . . . . . . . . . . . . 14 93 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 95 1. Requirements notation 96 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 97 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 98 document are to be interpreted as described in [RFC2119]. 100 2. Introduction 102 IPv6 provides global end to end IP reachability from the Internet and 103 into the Home Network. End Users to access services hosted in the 104 Home Network with IPv6 addresses would prefer to use names instead of 105 long and complex IPv6 addresses. 107 CPEs are already providing IPv6 connectivity to the Home Network and 108 generally provide IPv6 addresses or prefixes to the nodes of the Home 109 Network. This makes the CPEs a good candidate to manage binding 110 between names and IP addresses of the nodes. In other words, the CPE 111 is the natural candidate for setting the DNS(SEC) zone file. 113 CPEs are usually low powered devices designed for the Home Network, 114 but not for heavy traffic. CPEs can host the Naming Service for the 115 Home Network but should not be exposed on the Internet. This would 116 expose the CPE to resource exhaustion. As a consequence, it may 117 isolate the Home Network from the Internet and affects the services 118 hosted by the CPEs, thus affecting Home Network communications. As a 119 result, CPE SHOULD NOT host the Naming Service of the Home Network 120 for resolutions coming from the Internet. 122 Similarly, CPEs have not been designed to handle heavy computation 123 such as DNSSEC zone signing. Such operations could also result in 124 CPE resource exhaustion. As a consequence, resource expensive 125 operations such as zone signing SHOULD NOT be handled by the CPE, but 126 SHOULD be handled by other third party. 128 In addition to heavy operations such as zone signing, DNSSEC comes 129 with complex configurations as well as complex operation management 130 like (DNSSEC secure delegation, DNSSEC key roll over, DNSSEC zone 131 updates). These operations can hardly be understood by the average 132 end user, and a misconfiguration MAY result in invalid naming 133 resolutions that MAY make an host, or the whole home network 134 unreachable. As a consequence, DNSSEC management operations SHOULD 135 NOT be handled by the average end user, but SHOULD be handled by a 136 third party. 138 The goal of this document is to describe an architecture where the 139 CPE outsources the authoritative naming service and DNSSEC zone 140 management to a third party designated as Public Authoritative 141 Servers. This document describes the involved protocols as well as 142 their respective configurations to properly set the homenet naming 143 architecture. 145 The document is organized as follows. Section 4 provides an overview 146 of the homenet naming architecture and presents the CPE and the 147 Public Authoritative Server that handles the authoritative naming 148 service of the home network as well as DNSSEC management operations 149 on behalf of the CPE. Section 5 describes in details protocols and 150 configurations to set the homenet naming architecture. Section 6 151 sums up the various configuration parameters that MAY be filled by 152 the end user on the CPE for example via a GUI. Finally Section 7 153 provides security considerations. 155 3. Terminology 157 - Customer Premises Equipment: (CPE) is the router providing 158 connectivity to the home network. It is configured and managed 159 by the end user. In this document, the CPE MAY also hosts 160 services such as DHCPv6. This device MAY be provided by the 161 ISP. 163 - Registered Homenet Domain: is the Domain Name associated to the 164 home network. 166 - DNS Homenet Zone: is the DNS zone associated to the home network. 167 This zone is set by the CPE and essentially contains the 168 bindings between names and IP addresses of the nodes of the 169 home network. In this document, the CPE does neither perform 170 any DNSSEC management operations such as zone signing nor 171 provide an authoritative service for the zone. Both are 172 delegated to the Public Authoritative Server. The CPE 173 synchronizes the DNS Homenet Zone with the Public Authoritative 174 Server via a hidden master / slave architecture. The Public 175 Authoritative Server MAY use specific servers for the 176 synchronization of the DNS Homenet Zone: the Public 177 Authoritative Name Server Set. 179 - Public Authoritative Server: performs DNSSEC management 180 operations as well as provides the authoritative service for 181 the zone. In this document, the Public Authoritative Server 182 synchronizes the DNS Homenet Zone with the CPE via a hidden 183 master / slave architecture. The Public Authoritative Server 184 acts as a slave and MAY use specific servers called Public 185 Authoritative Name Server Set. Once the Public Authoritative 186 Server synchronizes the DNS Homenet Zone, it signs the zone and 187 generates the DNSSEC Public Zone. Then the Public 188 Authoritative Server hosts the zone as an authoritative server 189 on the Public Authoritative Master(s). 191 - DNSSEC Public Zone: corresponds to the signed version of the DNS 192 Homenet Zone. It is hosted by the Public Authoritative Server, 193 which is authoritative for this zone, and is reachable on the 194 Public Authoritative Master(s). 196 - Public Authoritative Master(s): are the visible name server 197 hosting the DNSSEC Public Zone. End users' resolutions for the 198 Homenet Domain are sent to this server, and this server is a 199 master for the zone. 201 - Public Authoritative Name Server Set: is the server the CPE 202 synchronizes the DNS Homenet Zone. It is configured as a slave 203 and the CPE acts as master. The CPE sends information so the 204 DNSSEC zone can be set and served. 206 4. Architecture Overview 208 Figure 1 provides an overview of the homenet naming architecture. 210 The CPE is in charge of building the DNS Homenet Zone that contains 211 all FQDN bindings of the home network. The home network is 212 associated to a FQDN, the Registered Homenet Domain (example.com). 213 Any node in the home network is associated to a FQDN 214 (node1.example.com) that MAY be provided via DHCP or statically 215 configured on the CPE via a GUI for example. 217 The goal of the homenet naming architecture is that the CPE does not 218 handle any DNSSEC operations and does not host the authoritative 219 naming service while FQDNs in the Homenet Zone can be resolved with 220 DNSSEC by any node on the Internet. 222 In order to achieve this goal, when a node on the Internet sends a 223 DNS(SEC) query like for node1.example.com, this DNS(SEC) query MUST 224 be treated by a third party designated in figure 1 as the Public 225 Authoritative Servers. 227 The Public Authoritative Servers are in charge of DNS(SEC) traffic 228 for the Registered Homenet Domain (example.com) as well as all DNSSEC 229 management operations like zone signing, key rollover. The DNSSEC 230 zone hosted by the Public Authoritative Servers is called the DNSSEC 231 Public Zone. 233 The purpose of our architecture is to describe how the CPE can 234 outsource the DNS Homenet Zone hosted on the CPE to the DNSSEC Public 235 Zone hosted on the Public Authoritative Servers. This includes 236 description of the synchronization protocols between the CPE and the 237 Public Authoritative Servers in Section 5.1 as well as configurations 238 of the DNS Homenet Zone Section 5.2. 240 home network +-------------------+ Internet 241 | | 242 | CPE | 243 | | +----------------------+ 244 +-------+ |+-----------------+| | Public Authoritative | 245 | | || DNS Homenet Zone|| | Servers | 246 | node1 | || || |+--------------------+| 247 | | || Homenet Domain || || DNSSEC Public Zone || 248 +-------+ || Name ||=========|| || 249 || (example.com) || ^ || (example.com) || 250 node1.\ |+-----------------+| | |+--------------------+| 251 example.com +-------------------+ | +----------------------+ 252 | ^ | 253 Synchronization | | 254 | | 255 DNSSEC resolution for node1.example.com | v 256 +----------------------+ 257 | | 258 | DNSSEC Resolver | 259 | | 260 +----------------------+ 262 Figure 1: Homenet Naming Architecture Description 264 The content of the DNS Homenet Zone is out of the scope of this 265 document. The CPE MAY host multiple services like a web GUI, DHCP 266 [RFC6644] or mDNS [RFC6762]. These services MAY coexist and MAY be 267 used to populate the DNS Homenet Zone. This document does not 268 address this issue. 270 CPE MAY chose to host an authoritative naming server for the home 271 network. Whether this service is implemented or not on the CPE is 272 out of the scope of this document. Some implementations MAY chose to 273 set a DNS authoritative server for the DNS Homenet Zone for 274 resolutions coming from the home network. Other implementations MAY 275 chose to synchronize the DNSSEC zone on the Public Authoritative 276 Servers to provide DNSSEC responses. This latest option MAY require 277 specific configurations on the Public Authoritative Servers. 279 Similarly, CPE MAY host a DNS(SEC) resolution service for nodes in 280 the home network. There are multiple ways to configure the resolver 281 service on the CPE. Detailing these various configurations is out of 282 the scope of this document, and is considered as an implementation 283 issue. Some implementers MAY chose to forward DNS(SEC) queries from 284 the home network to the resolving server of its ISP or any other 285 public resolver. In that case, the DNS(SEC) response from the Public 286 Authoritative Servers is forwarded to the home network, which provide 287 DNS and DNSSEC resolution for the home network. Alternative 288 implementations MAY chose to lookup in the DNS Homenet Zone, and thus 289 provide only DNS responses in the home network. Other implementation 290 MAY chose to synchronize the DNSSEC Public Zone on the CPE either 291 using DNS master slave mechanisms, or by caching the whole zone. 292 This latest option MAY require some additional configuration the 293 Public Authoritative Servers. 295 5. Architecture Description 297 This section describes how the CPE and the Public Authoritative 298 Servers SHOULD be configured to outsource authoritative naming 299 service as well as DNSSEC management operations. Section 5.1 300 describes how a secure synchronization between the CPE and the Public 301 Authoritative server is set. Section 5.2 provides guide lines for 302 the DNS Homenet Zone set in the CPE and uploaded on the Public 303 Authoritative Servers. Section 5.3 describes DNSSEC settings on the 304 Public Authoritative Servers. Finally, Section 5.4 provides the 305 security policies that SHOULD be set on the CPE. 307 5.1. CPE and Public Authoritative Servers Synchronization 309 5.1.1. Synchronization with a Hidden Master 311 Uploading and dynamically updating the zone file on the Public 312 Servers can be seen as zone provisioning between the CPE (Hidden 313 Master) and the Public Server (Slave Server). This can be handled 314 either in band or out of band. DNS dynamic update [RFC2136] may be 315 used. However, in this section we detail how to take advantage of 316 the DNS slave / master architecture to deploy updates to public 317 zones. 319 The Public Authoritative Server is configured as a slave for the 320 Homenet Domain Name. This slave configuration has been previously 321 agreed between the end user and the provider of the Public 322 Authoritative Servers. In order to set the master/ slave 323 architecture, the CPE acts as a Hidden Master Server, which is a 324 regular Authoritative DNS(SEC) Server listening on the WAN interface. 326 The Hidden Master Server is only expected to initiate AXFR [RFC1034], 327 IXFR [RFC1995] transfers to configured slave DNS servers. The Hidden 328 Master Server SHOULD send NOTIFY messages [RFC1996] in order to 329 update Public DNS server zones as updates occur. 331 Hidden Master Server differs from a regular authoritative server for 332 the home network by: 334 - Interface Binding: the Hidden Master Server listens on the WAN 335 Interface, whereas a regular authoritative server for the home 336 network would listen on the home network interface. 338 - Limited exchanges: the purpose of the Hidden Master Server is to 339 synchronizes with the Public Authoritative Servers, not to 340 serve zone. As a result, exchanges are performed with specific 341 nodes (the Public Authoritative Servers). Then exchange types 342 are limited. The only legitimate exchanges are: NOTIFY 343 initiated by the Hidden Master and IXFR or AXFR exchanges 344 initiated by the Public Authoritative Servers. On the other 345 hand regular authoritative servers would respond any hosts on 346 the home network, and any DNS(SEC) query would be considered. 347 The CPE SHOULD filter IXFR/AXFR traffic and drop traffic not 348 initiated by the Public Authoritative Server. The CPE MUST 349 listen for DNS on TCP and UDP and at least allow SOA lookups to 350 the DNS Homenet Zone. 352 5.1.2. Securing Synchronization 354 Exchange between the Public Servers and the CPE MUST be secured, at 355 least for integrity protection and for authentication. This is the 356 case whatever mechanism is used between the CPE and the Public 357 Authoritative DNS(SEC) Servers. 359 TSIG [RFC2845] can be used to secure the DNS communications between 360 the CPE and the Public DNS(SEC) Servers. TKEY [RFC2931] can be used 361 for re-keying the key used for TSIG. The advantage of this mechanism 362 is that this mechanisms are only associated with the DNS application. 363 Not relying on shared libraries ease testing and integration. On the 364 other hand, using TSIG and TKEY requires that this mechanism is 365 implemented on the DNS(SEC) Server's implementation running on the 366 CPE, which adds codes. Another disadvantage is that TKEY does not 367 provides authentication mechanism. 369 Protocols like TLS [RFC5246] / DTLS [RFC6347] can be used to secure 370 the transactions between the Public Authoritative Servers and the 371 CPE. The advantage of TLS/DTLS is that this technology is widely 372 deployed, and most of the boxes already embeds a TLS/DTLS libraries, 373 eventually taking advantage of hardware acceleration. Then TLS/DTLS 374 provides authentication facilities and can use certificates to 375 authenticate the Public Authoritative Server and the CPE. On the 376 other hand, using TLS/DTLS requires to integrate DNS exchange over 377 TLS/DTLS, as well as a new service port. This is why we do not 378 recommend this option. 380 IPsec [RFC4301] IKEv2 [RFC5996] can also be used to secure the 381 transactions between the CPE and the Public Authoritative Servers. 383 Similarly to TLS/DTLS, most CPE already embeds a IPsec stack, and 384 IKEv2 provides multiple authentications possibilities with its EAP 385 framework. In addition, IPsec can be used to protect the DNS 386 exchanges between the CPE and the Public Authoritative Servers 387 without any modifications of the DNS Servers or client. DNS 388 integration over IPsec only requires an additional security policy in 389 the Security Policy Database. One disadvantage of IPsec is that it 390 hardly goes through NATs and firewalls. However, in our case, the 391 CPE is connected to the Internet, and IPsec communication between the 392 CPE and Public Authoritative Server SHOULD NOT be impacted by middle 393 boxes. 395 As mentioned above, TSIG, IPsec and TLS/DTLS may be used to secure 396 transactions between the CPE and the Public Authentication Servers. 397 The CPE and Public Authoritative Server SHOULD implement TSIG and 398 IPsec. 400 How the PSK can be used by any of the TSIG, TLS/DTLS or IPsec 401 protocols. Authentication based on certificates implies a mutual 402 authentication and thus requires the CPE to manage a private key, a 403 public key or certificates as well as Certificate Authorities. This 404 adds complexity to the configuration especially on the CPE side. For 405 this reason, we recommend that CPE MAY use PSK or certificate base 406 authentication and that Public Authentication Servers MUST support 407 PSK and certificate based authentication. 409 5.2. DNS Homenet Zone configuration 411 As depicted in figure 1, he DNSSEC Public Zone is hosted on the 412 Public Authoritative Server, whereas the DNS Homenet Zone is hosted 413 on the CPE. As a result, the CPE MUST configure the DNS Homenet Zone 414 as if the DNS Homenet Zone were hosted by the Public Authoritative 415 Servers instead of the CPE. 417 If one considers the case where the CPE has a single Homenet Domain 418 Name and has an agreement with a single Public Authoritative Server. 419 In that case, the DNS Homenet Zone SHOULD configure its Name Server 420 RRset and Start of Authority with the ones associated to the Public 421 Authoritative Servers. This is illustrated in figure 2. 422 public.autho.servers.example.net is the domain name associated to the 423 Public Authoritative Server, and IP1, IP2, IP3, IP4 are the IP 424 addresses associated. 426 $ORIGIN example.com 427 $TTL 1h 429 @ IN SOA public.autho.servers.example.net 430 user.example.com. ( 432 2013120710 ; serial number of this zone file 433 1d ; slave refresh 434 2h ; slave retry time in case of a problem 435 4w ; slave expiration time 436 1h ; maximum caching time in case of failed 437 ; lookups 438 ) 440 @ NS public.authoritative.servers.example.net 442 public.autho.servers.example.net A @IP1 443 public.autho.servers.example.net A @IP2 444 public.autho.servers.example.net AAAA @IP3 445 public.autho.servers.example.net AAAA @IP4 447 Figure 2: DNS Homenet Zone 449 When the end user considers multiple Public Authoritative Servers for 450 a given Registered Homenet Domain, the DNS Homenet Zone MAY contain 451 all associated Name Servers and IP addresses. 453 Some additional verification can check whether the CPE IP address is 454 mentioned in the Public Zone file, and raise a warning to the End 455 User. 457 5.3. DNSSEC outsourcing configuration 459 In this document we assumed that the Public Authoritative Server 460 signs the DNS Homenet Zone. Multiple variants MAY be proposed by the 461 Public Authoritative Servers. Public Authoritative Servers MAY 462 propose to sign the DNS Homenet Zone with keys generated by the 463 Public Authoritative Servers and unknown to the CPE. Alternatively 464 some MAY propose the end user to provide the private keys. Although 465 not considered in this document some end user MAY still prefer to 466 sign their zone with their own keys they do not communicate to the 467 Public Authoritative Servers. All these alternatives result from a 468 negotiation between the end user and the Public Authoritative 469 Servers. This negotiation is performed out-of-band and is out of 470 scope of this document. 472 In this document, we consider that the Public Authoritative Server 473 has all the necessary cryptographic elements to perform zone signing 474 and key management operations. 476 Note that Public Authoritative Servers described in this document 477 accomplish different functions, and thus different entities MAY be 478 involved. 480 - DNS Slave function synchronizes the DNS Homenet Zone between the 481 CPE and the Public Authoritative Servers. The DNS Homenet Zone 482 on the Public Authoritative Servers is not available, and the 483 Public Authoritative Server MUST NOT address any DNS queries 484 for that zone. As a result, the Public Authoritative Servers 485 MAY chose a dedicated set of servers to serve the DNS Homenet 486 Zone: the Public Authoritative Name Server Set. 488 - DNS Zone Signing function signs the DNS Zone Homenet Zone to 489 generate an DNSSEC Public Zone. 491 - DNSSEC Authoritative Server hosts the naming service for the 492 DNSSEC Public Zone. Any DNS(SEC) query associated to the 493 Homenet Zone SHOULD be done using the specific servers 494 designated as the Public Authoritative Master(s). 496 5.4. CPE Security Policies 498 This section details security policies related to the Hidden Master / 499 Slave synchronization. 501 The Hidden Master, as described in this document SHOULD drop any 502 queries from the home network. This can be performed with port 503 binding and/or firewall rules. 505 The Hidden Master SHOULD drop on the WAN interface any DNS queries 506 that is not issued from the Public Authoritative Server Name Server 507 Set. 509 The Hidden Master SHOULD drop any outgoing packets other than DNS 510 NOTIFY query, SOA response, IXFR response or AXFR responses. 512 The Hidden Master SHOULD drop any incoming packets other than DNS 513 NOTIFY response, SOA query, IXFR query or AXFR query. 515 The Hidden Master SHOULD drop any non protected IXFR or AXFR 516 exchange. This depends how the synchronization is secured. 518 6. Homenet Naming Configuration 520 This section specifies the various parameters required by the CPE to 521 configure the naming architecture of this document. This section is 522 informational, and is intended to clarify the information handled by 523 the CPE and the various settings to be done. 525 Public Authoritative Servers MAY be defined with the following 526 parameters. These parameters are necessary to establish a secure 527 channel between the CPE and the Public Authoritative Server, and to 528 set the appropriated DNS Homenet Zone file: 530 - Public Authoritative Name Server Set: The associated FQDNs or IP 531 addresses of the Public Authoritative Server. IP addresses are 532 optional and the FQDN is sufficient. To secure the binding 533 name and IP addresses, a DNSSEC exchange is required. 534 Otherwise, the IP addresses SHOULD be entered manually. 536 - Authentication Method: How the CPE authenticates itself to the 537 Public Server. This MAY depend on the implementation but we 538 should consider at least IPsec, DTLS and TSIG 540 - Authentication data: Associated Data. PSK only requires a single 541 argument. If other authentication mechanisms based on 542 certificates are used, then, files for the CPE private keys, 543 certificates and certification authority SHOULD be specified. 545 - Public Authoritative Master(s): The FQDN or IP addresses of the 546 Public Authoritative Master. It corresponds to the data that 547 will be set in the NS RRsets and SOA of the DNS Homenet Zone. 548 IP addresses are optional and the FQDN is sufficient. To 549 secure the binding name and IP addresses, a DNSSEC exchange is 550 required. Otherwise, the IP addresses SHOULD be entered 551 manually. 553 - Registered Homenet Domain: The domain name the Public 554 Authoritative is configured for DNS slave, DNSSEC zone signing 555 and DNSSEC zone hosting. 557 Setting the DNS Homenet Zone requires the following information. 559 - Registered Homenet Domain: The Domain Name of the zone. Multiple 560 Registered Homenet Domain MAY be provided. This will generate 561 the creation of multiple DNS Homenet Zones. 563 - Public Authoritative Server: The Public Authoritative Servers 564 associated to the Registered Homenet Domain. Multiple Public 565 Authoritative Server MAY be provided. 567 7. Security Considerations 569 The Homenet Naming Architecture described in this document solves 570 exposing the CPE's DNS service as a DoS attack vector. 572 7.1. Names are less secure than IP addresses 574 This document describes how an End User can make his services and 575 devices from his Home Network reachable on the Internet with Names 576 rather than IP addresses. This exposes the Home Network to attackers 577 since names are expected to provide less randomness than IP 578 addresses. The naming delegation protects the End User's privacy by 579 not providing the complete zone of the Home Network to the ISP. 580 However, using the DNS with names for the Home Network exposes the 581 Home Network and its components to dictionary attacks. In fact, with 582 IP addresses, the Interface Identifier is 64 bit length leading to 583 2^64 possibilities for a given subnetwork. This is not to mention 584 that the subnet prefix is also of 64 bit length, thus providing 585 another 2^64 possibilities. On the other hand, names used either for 586 the Home Network domain or for the devices present less randomness 587 (livebox, router, printer, nicolas, jennifer, ...) and thus exposes 588 the devices to dictionary attacks. 590 7.2. Names are less volatile than IP addresses 592 IP addresses may be used to locate a device, a host or a Service. 593 However, Home Networks are not expected to be assigned the same 594 Prefix over time. As a result observing IP addresses provides some 595 ephemeral information about who is accessing the service. On the 596 other hand, Names are not expected to be as volatile as IP addresses. 597 As a result, logging Names, over time, may be more valuable that 598 logging IP addresses, especially to profile End User's 599 characteristics. 601 PTR provides a way to bind an IP address to a Name. In that sense 602 responding to PTR DNS queries may affect the End User's Privacy. For 603 that reason we recommend that End Users may choose to respond or not 604 to PTR DNS queries and may return a NXDOMAIN response. 606 8. IANA Considerations 608 This document has no actions for IANA. 610 9. Acknowledgment 612 The authors wish to thank Philippe Lemordant for its contributions on 613 the early versions of the draft, Ole Troan for pointing out issues 614 with the IPv6 routed home concept and placing the scope of this 615 document in a wider picture, Mark Townsley for encouragement and 616 injecting a healthy debate on the merits of the idea, Ulrik de Bie 617 for providing alternative solutions, Paul Mockapetris, Christian 618 Jacquenet, Francis Dupont and Ludovic Eschard for their remarks on 619 CPE and low power devices. 621 10. Normative References 623 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 624 STD 13, RFC 1034, November 1987. 626 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 627 August 1996. 629 [RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone 630 Changes (DNS NOTIFY)", RFC 1996, August 1996. 632 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 633 Requirement Levels", BCP 14, RFC 2119, March 1997. 635 [RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound, 636 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 637 RFC 2136, April 1997. 639 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake, D., and B. 640 Wellington, "Secret Key Transaction Authentication for DNS 641 (TSIG)", RFC 2845, May 2000. 643 [RFC2931] Eastlake, D., "DNS Request and Transaction Signatures ( 644 SIG(0)s)", RFC 2931, September 2000. 646 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 647 Internet Protocol", RFC 4301, December 2005. 649 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 650 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 652 [RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, 653 "Internet Key Exchange Protocol Version 2 (IKEv2)", RFC 654 5996, September 2010. 656 [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer 657 Security Version 1.2", RFC 6347, January 2012. 659 [RFC6644] Evans, D., Droms, R., and S. Jiang, "Rebind Capability in 660 DHCPv6 Reconfigure Messages", RFC 6644, July 2012. 662 [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, 663 February 2013. 665 Appendix A. Document Change Log 667 [RFC Editor: This section is to be removed before publication] 668 -02: 670 *remove interfaces: "Public Authoritative Server Naming Interface" is 671 replaced by "Public Authoritative Master(s)". "Public Authoritative 672 Server Management Interface" is replaced by "Public Authoritative 673 Name Server Set". 675 -01.3: 677 *remove the authoritative / resolver services of the CPE. 678 Implementation dependent 680 *remove interactions with mdns and dhcp. Implementation dependent. 682 *remove considerations on low powered devices 684 *remove position toward homenet arch 686 *remove problem statement section 688 -01.2: 690 * add a CPE description to show that the architecture can fit CPEs 692 * specification of the architecture for very low powered devices. 694 * integrate mDNS and DHCP interactions with the Homenet Naming 695 Architecture. 697 * Restructuring the draft. 1) We start from the homenet-arch draft to 698 derive a Naming Architecture, then 2) we show why CPE need mechanisms 699 that do not expose them to the Internet, 3) we describe the 700 mechanisms. 702 * I remove the terminology and expose it in the figures A and B. 704 * remove the Front End Homenet Naming Architecture to Homenet Naming 706 -01: 708 * Added C. Griffiths as co-author. 710 * Updated section 5.4 and other sections of draft to update section 711 on Hidden Master / Slave functions with CPE as Hidden Master/Homenet 712 Server. 714 * For next version, address functions of MDNS within Homenet Lan and 715 publishing details northbound via Hidden Master. 717 -00: First version published. 719 Authors' Addresses 721 Daniel Migault 722 Francetelecom - Orange 723 38 rue du General Leclerc 724 92794 Issy-les-Moulineaux Cedex 9 725 France 727 Phone: +33 1 45 29 60 52 728 Email: mglt.ietf@gmail.com 730 Wouter Cloetens 731 SoftAtHome 732 vaartdijk 3 701 733 3018 Wijgmaal 734 Belgium 736 Email: wouter.cloetens@softathome.com 738 Chris Griffiths 739 Dyn 740 150 Dow Street 741 Manchester, NH 03101 742 US 744 Email: cgriffiths@dyn.com 745 URI: http://dyn.com 747 Ralf Weber 748 Nominum 749 2000 Seaport Blvd #400 750 Redwood City, CA 94063 751 US 753 Email: ralf.weber@nominum.com 754 URI: http://www.nominum.com