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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reference: RFC 5246 (Obsoleted by RFC 8446) ** Obsolete normative reference: RFC 6347 (Obsoleted by RFC 9147) == Outdated reference: A later version (-06) exists of draft-ietf-dnssd-requirements-04 == Outdated reference: A later version (-24) exists of draft-ietf-homenet-naming-architecture-dhc-options-00 Summary: 3 errors (**), 0 flaws (~~), 3 warnings (==), 1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 Ericsson 4 Intended status: Standards Track W. Cloetens 5 Expires: August 20, 2015 SoftAtHome 6 C. Griffiths 7 Dyn 8 R. Weber 9 Nominum 10 February 16, 2015 12 Outsourcing Home Network Authoritative Naming Service 13 draft-ietf-homenet-front-end-naming-delegation-01.txt 15 Abstract 17 CPEs are designed to provide IP connectivity to home networks. Most 18 CPEs assign IP addresses to the nodes of the home network which makes 19 it a good candidate for hosting the naming service. With IPv6, the 20 naming service makes nodes reachable from the home network as well as 21 from the Internet. 23 However, CPEs have not been designed to host such a naming service 24 exposed on the Internet. This may expose the CPEs to resource 25 exhaustion which would make the home network unreachable, and most 26 probably would also affect the home network inner communications. 28 In addition, DNSSEC management and configuration may not be well 29 understood or mastered by regular end users. Misconfiguration may 30 also results in naming service disruption, thus these end users may 31 prefer to rely on third party naming providers. 33 This document describes a homenet naming architecture where the CPEs 34 manage the DNS zone associates to its home network, and outsources 35 the naming service and eventually the DNSSEC management on the 36 Internet to a third party designated as the Public Authoritative 37 Servers. 39 Status of This Memo 41 This Internet-Draft is submitted in full conformance with the 42 provisions of BCP 78 and BCP 79. 44 Internet-Drafts are working documents of the Internet Engineering 45 Task Force (IETF). Note that other groups may also distribute 46 working documents as Internet-Drafts. The list of current Internet- 47 Drafts is at http://datatracker.ietf.org/drafts/current/. 49 Internet-Drafts are draft documents valid for a maximum of six months 50 and may be updated, replaced, or obsoleted by other documents at any 51 time. It is inappropriate to use Internet-Drafts as reference 52 material or to cite them other than as "work in progress." 54 This Internet-Draft will expire on August 20, 2015. 56 Copyright Notice 58 Copyright (c) 2015 IETF Trust and the persons identified as the 59 document authors. All rights reserved. 61 This document is subject to BCP 78 and the IETF Trust's Legal 62 Provisions Relating to IETF Documents 63 (http://trustee.ietf.org/license-info) in effect on the date of 64 publication of this document. Please review these documents 65 carefully, as they describe your rights and restrictions with respect 66 to this document. Code Components extracted from this document must 67 include Simplified BSD License text as described in Section 4.e of 68 the Trust Legal Provisions and are provided without warranty as 69 described in the Simplified BSD License. 71 Table of Contents 73 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 74 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 75 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 76 4. Architecture Description . . . . . . . . . . . . . . . . . . 5 77 4.1. Architecture Overview . . . . . . . . . . . . . . . . . . 5 78 4.2. Example: DNS(SEC) Homenet Zone . . . . . . . . . . . . . 7 79 4.3. Example: CPE necessary parameters for outsourcing . . . . 9 80 5. Synchronization between CPE and Public Authoritative Servers 10 81 5.1. Synchronization with a Hidden Master . . . . . . . . . . 10 82 5.2. Securing Synchronization . . . . . . . . . . . . . . . . 11 83 5.3. CPE Security Policies . . . . . . . . . . . . . . . . . . 13 84 6. DNSSEC compliant Homenet Architecture . . . . . . . . . . . . 13 85 6.1. Zone Signing . . . . . . . . . . . . . . . . . . . . . . 13 86 6.2. Secure Delegation . . . . . . . . . . . . . . . . . . . . 15 87 7. Handling Different Views . . . . . . . . . . . . . . . . . . 15 88 7.1. Motivations . . . . . . . . . . . . . . . . . . . . . . . 16 89 7.2. Consequences . . . . . . . . . . . . . . . . . . . . . . 16 90 7.3. Guidance and Recommendations . . . . . . . . . . . . . . 17 91 8. Reverse Zone . . . . . . . . . . . . . . . . . . . . . . . . 17 92 9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18 93 10. Security Considerations . . . . . . . . . . . . . . . . . . . 19 94 10.1. Names are less secure than IP addresses . . . . . . . . 19 95 10.2. Names are less volatile than IP addresses . . . . . . . 19 96 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 97 12. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 20 98 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 99 13.1. Normative References . . . . . . . . . . . . . . . . . . 20 100 13.2. Informational References . . . . . . . . . . . . . . . . 21 101 Appendix A. Document Change Log . . . . . . . . . . . . . . . . 22 102 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 104 1. Requirements notation 106 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 107 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 108 document are to be interpreted as described in [RFC2119]. 110 2. Introduction 112 IPv6 provides global end to end IP reachability. To access services 113 hosted in the home network with IPv6 addresses, end users prefer to 114 use names instead of long and complex IPv6 addresses. 116 CPEs are already providing IPv6 connectivity to the home network and 117 generally provide IPv6 addresses or prefixes to the nodes of the home 118 network. This makes the CPEs a good candidate to manage binding 119 between names and IP addresses of the nodes. In addition, [RFC7368] 120 recommends that home networks be resilient to connectivity disruption 121 from the ISP. This requires that a dedicate device inside the home 122 network manage bindings between names and IP addresses of the nodes 123 and builds the DNS Homenet Zone. All this makes the CPE the natural 124 candidate for setting the DNS(SEC) zone file of the home network. 126 CPEs are usually low powered devices designed for the home network, 127 but not for heavy traffic. As a result, hosting the an authoritative 128 DNS service on the Internet may expose the home network to resource 129 exhaustion, which may isolate the home network from the Internet and 130 affect the services hosted by the CPEs, thus affecting the overall 131 home network communications. 133 In order to avoid resource exhaustion, this document describes an 134 architecture that outsources the authoritative naming service of the 135 home network. More specifically, the DNS(SEC) Homenet Zone built by 136 the CPE is outsourced to Public Authoritative Servers. These servers 137 publish the corresponding DN(SEC) Public Zone on the Internet. 138 Section 4.1 describes the architecture. In order to keep the 139 DNS(SEC) Public Zone up-to-date Section 5 describes how the DNS(SEC) 140 Homenet Zone and the DN(SEC) Public Zone can be synchronized. The 141 proposed architecture aims at deploying DNSSEC and the DNS(SEC) 142 Public Zone is expected to be signed with a secure delegation. The 143 zone signing and secure delegation can be performed either by the CPE 144 or by the Public Authoritative Servers. Section 6 discusses these 145 two alternatives. Section 7 discusses multiple views aspects and 146 provide guidance to avoid them. Section 8 discusses the case of the 147 reverse zone. Section 9 and Section 10 respectively discuss privacy 148 and security considerations when outsourcing the DNS Homenet Zone. 150 3. Terminology 152 - Customer Premises Equipment: (CPE) is the router providing 153 connectivity to the home network. It is configured and managed 154 by the end user. In this document, the CPE MAY also hosts 155 services such as DHCPv6. This device MAY be provided by the 156 ISP. 158 - Registered Homenet Domain: is the Domain Name associated to the 159 home network. 161 - DNS Homenet Zone: is the DNS zone associated to the home network. 162 This zone is set by the CPE and essentially contains the 163 bindings between names and IP addresses of the nodes of the 164 home network. In this document, the CPE does neither perform 165 any DNSSEC management operations such as zone signing nor 166 provide an authoritative service for the zone. Both are 167 delegated to the Public Authoritative Server. The CPE 168 synchronizes the DNS Homenet Zone with the Public Authoritative 169 Server via a hidden master / slave architecture. The Public 170 Authoritative Server MAY use specific servers for the 171 synchronization of the DNS Homenet Zone: the Public 172 Authoritative Name Server Set as public available name servers 173 for the Registered Homenet Domain. 175 - DNS Homenet Reverse Zone: The reverse zone file associated to the 176 DNS Homenet Zone. 178 - Public Authoritative Server: performs DNSSEC management 179 operations as well as provides the authoritative service for 180 the zone. In this document, the Public Authoritative Server 181 synchronizes the DNS Homenet Zone with the CPE via a hidden 182 master / slave architecture. The Public Authoritative Server 183 acts as a slave and MAY use specific servers called Public 184 Authoritative Name Server Set. Once the Public Authoritative 185 Server synchronizes the DNS Homenet Zone, it signs the zone and 186 generates the DNSSEC Public Zone. Then the Public 187 Authoritative Server hosts the zone as an authoritative server 188 on the Public Authoritative Master(s). 190 - DNSSEC Public Zone: corresponds to the signed version of the DNS 191 Homenet Zone. It is hosted by the Public Authoritative Server, 192 which is authoritative for this zone, and is reachable on the 193 Public Authoritative Master(s). 195 - Public Authoritative Master(s): are the visible name server 196 hosting the DNSSEC Public Zone. End users' resolutions for the 197 Homenet Domain are sent to this server, and this server is a 198 master for the zone. 200 - Public Authoritative Name Server Set: is the server the CPE 201 synchronizes the DNS Homenet Zone. It is configured as a slave 202 and the CPE acts as master. The CPE sends information so the 203 DNSSEC zone can be set and served. 205 - Reverse Public Authoritative Master(s): are the visible name 206 server hosting the DNS Homenet Reverse Zone. End users' 207 resolutions for the Homenet Domain are sent to this server, and 208 this server is a master for the zone. 210 - Reverse Public Authoritative Name Server Set: is the server the 211 CPE synchronizes the DNS Homenet Reverse Zone. It is 212 configured as a slave and the CPE acts as master. The CPE 213 sends information so the DNSSEC zone can be set and served. 215 4. Architecture Description 217 This section describes the architecture for outsourcing the 218 authoritative naming service from the CPE to the Public Authoritative 219 Master(s). Section 4.1 describes the architecture, Section 4.2 and 220 Section 4.3 illustrate this architecture and shows how the DNS(SEC) 221 Homenet Zone should be built by the CPE, as well as lists the 222 necessary parameters the CPE needs to outsource the authoritative 223 naming service. These two section are informational and non 224 normative. 226 4.1. Architecture Overview 228 Figure 1 provides an overview of the architecture. 230 The home network is designated by the Registered Homenet Domain Name 231 -- example.com in Figure 1. The CPE builds the DNS(SEC) Homenet Zone 232 associated to the home network. How the DNS(SEC) Homenet Zone is 233 built is out of the scope of this document. The CPE may host and 234 involve multiple services like a web GUI, DHCP [RFC6644] or mDNS 235 [RFC6762]. These services may coexist and may be used to populate 236 the DNS Homenet Zone. This document assumes the DNS(SEC) Homenet 237 Zone has been populated with domain names that are intended to be 238 publicly published and that are publicly reachable. More 239 specifically, names associated to services or devices that are not 240 expected to be reachable from outside the home network or names bound 241 to non globally reachable IP addresses MUST NOT be part of the 242 DNS(SEC) Homenet Zone. 244 Once the DNS(SEC) Homenet Zone has been built, the CPE does not host 245 the authoritative naming service for it, but instead outsources it to 246 the Public Authoritative Servers. The Public Authoritative Servers 247 take the DNS(SEC) Homenet as an input and publishes the DNS(SEC) 248 Public Zone. In fact the DNS(SEC) Homenet Zone and the DNS(SEC) 249 Public Zone have different names as they may be different. If the 250 CPE does not sign the DNS Homenet Zone, for example, the Public 251 Authoritative Servers may instead sign it on behalf of the CPE. 252 Figure 1 provides a more detailed description of the Public 253 Authoritative Servers, but overall, it is expected that the CPE 254 provides the DNS(SEC) Homenet Zone, the DNS(SEC) Public Zone is 255 derived from the DNS(SEC) Homenet Zone and published on the Internet. 257 As a result, DNS(SEC) queries from the DNS(SEC) Resolvers on the 258 Internet are answered by the Public Authoritative Server and do not 259 reach the CPE. Figure 1 illustrates the case of the resolution of 260 node1.example.com. 262 home network +-------------------+ Internet 263 | | 264 | CPE | 265 | | +----------------------+ 266 +-------+ |+-----------------+| | Public Authoritative | 267 | | || DNS(SEC) Homenet|| | Servers | 268 | node1 | || Zone || |+--------------------+| 269 | | || || ||DNS(SEC) Public Zone|| 270 +-------+ || Homenet Domain ||=========|| || 271 || Name || ^ || (example.com) || 272 node1.\ || (example.com) || | |+--------------------+| 273 example.com |+-----------------+| | +----------------------+ 274 +-------------------+ | ^ | 275 Synchronization | | 276 | | 277 DNSSEC resolution for node1.example.com | v 278 +----------------------+ 279 | | 280 | DNSSEC Resolver | 281 | | 282 +----------------------+ 284 Figure 1: Homenet Naming Architecture Description 286 The Public Authoritative Servers are described in Figure 2. The 287 Public Authoritative Name Server Set receives the DNS(SEC) Homenet 288 Zone as an input. The received zone may be transformed to output the 289 DNS(SEC) Public Zone. Various operations may be performed here, 290 however this document only considers zone signing as potential 291 operation. This could occur only when the CPE outsources this 292 operation to the Public Authoritative Name Server Set. On the other 293 hand, if the CPE signs the DNSSEC Homenet Zone itself, the zone it 294 collected by the Public Authoritative Name Server Set and directly 295 transferred to the Public Authoritative Master. Implications of such 296 policy are detailed in Section 6 and Section 7. 298 Internet 300 +--------------------------------------------------------+ 301 | Public Authoritative Servers | 302 +--------------------------------------------------------+ 304 +----------------------+ +----------------------+ 305 | | | | 306 | Public Authoritative | | Public Authoritative | 307 | Name Server Set | | Masters | 308 | | | | 309 | +------------------+ | X | +------------------+ | 310 | | DNS(SEC) Homenet | | ^ | | DNS(SEC) Public | | 311 =========>| | Zone | | | | | Zone | | 312 ^ | | | | | | | | | 313 | | | (example.com) | | | | | (example.com) | | 314 | | +------------------+ | | | +------------------+ | 315 | +----------------------+ | +----------------------+ 316 | Homenet to Public Zone 317 Synchronization transformation 318 from the CPE 320 Figure 2: Public Authoritative Servers Description 322 4.2. Example: DNS(SEC) Homenet Zone 324 This section is not normative and intends to illustrate how the CPE 325 builds the DNS(SEC) Homenet Zone. 327 As depicted in Figure 1 and Figure 2, the DNS(SEC) Public Zone is 328 hosted on the Public Authoritative Masters, whereas the DNS(SEC) 329 Homenet Zone is hosted on the CPE. Motivations for keeping these two 330 zones identical are detailed in Section 7, and this section considers 331 that the CPE builds the zone that will be effectively published on 332 the Public Authoritative Masters. In other words "Homenet to Public 333 Zone transformation" is the identity. 335 In that case, the DNS Homenet Zone should configure its Name Server 336 RRset (NS) and Start of Authority (SOA) with the ones associated to 337 the Public Authoritative Masters. This is illustrated in Figure 3. 338 public.masters.example.net is the FQDN of the Public Authoritative 339 Masters, and IP1, IP2, IP3, IP4 are the associated IP addresses. 340 Then the CPE should add the different new nodes that enter the home 341 network, remove those that should be removed and sign the DNS Homenet 342 Zone. 344 $ORIGIN example.com 345 $TTL 1h 347 @ IN SOA public.masters.example.net 348 hostmaster.example.com. ( 349 2013120710 ; serial number of this zone file 350 1d ; slave refresh 351 2h ; slave retry time in case of a problem 352 4w ; slave expiration time 353 1h ; maximum caching time in case of failed 354 ; lookups 355 ) 357 @ NS public.authoritative.servers.example.net 359 public.masters.example.net A @IP1 360 public.masters.example.net A @IP2 361 public.masters.example.net AAAA @IP3 362 public.masters.example.net AAAA @IP4 364 Figure 3: DNS Homenet Zone 366 The SOA RRset is defined in [RFC1033], [RFC1035] and [RFC2308]. This 367 SOA is specific as it is used for the synchronization between the 368 Hidden Master and the Public Authoritative Name Server Set and 369 published on the DNS Public Authoritative Master. 371 - MNAME: indicates the primary master. In our case the zone is 372 published on the Public Authoritative Master, and its name MUST 373 be mentioned. If multiple Public Authoritative Masters are 374 involved, one of them MUST be chosen. More specifically, the 375 CPE MUST NOT place the name of the Hidden Master. 377 - RNAME: indicates the email address to reach the administrator. 378 [RFC2142] recommends to use hostmaster@domain and replacing the 379 '@' sign by '.'. 381 - REFRESH and RETRY: indicate respectively in seconds how often 382 slaves need to check the master and the time between two 383 refresh when a refresh has failed. Default value indicated by 384 [RFC1033] are 3600 (1 hour) for refresh and 600 (10 minutes) 385 for retry. This value MAY be long for highly dynamic content. 386 However, Public Authoritative Masters and the CPE are expected 387 to implement NOTIFY [RFC1996]. Then short values MAY increase 388 the bandwidth usage for slaves hosting large number of zones. 389 As a result, default values looks fine. 391 EXPIRE: is the upper limit data SHOULD be kept in absence of 392 refresh. Default value indicated by [RFC1033] is 3600000 about 393 42 days. In home network architectures, the CPE provides both 394 the DNS synchronization and the access to the home network. 395 This device MAY be plug / unplugged by the end user without 396 notification, thus we recommend large period. 398 MINIMUM: indicates the minimum TTL. Default value indicated by 399 [RFC1033] is 86400 (1 day). For home network, this value MAY 400 be reduced, and 3600 (1hour) seems more appropriated. 402 4.3. Example: CPE necessary parameters for outsourcing 404 This section specifies the various parameters required by the CPE to 405 configure the naming architecture of this document. This section is 406 informational, and is intended to clarify the information handled by 407 the CPE and the various settings to be done. 409 Public Authoritative Name Server Set may be defined with the 410 following parameters. These parameters are necessary to establish a 411 secure channel between the CPE and the Public Authoritative Name 412 Server Set: 414 - Public Authoritative Name Server Set: The associated FQDNs or IP 415 addresses of the Public Authoritative Server. IP addresses are 416 optional and the FQDN is sufficient. To secure the binding 417 name and IP addresses, a DNSSEC exchange is required. 418 Otherwise, the IP addresses should be entered manually. 420 - Authentication Method: How the CPE authenticates itself to the 421 Public Server. This MAY depend on the implementation but we 422 should consider at least IPsec, DTLS and TSIG 424 - Authentication data: Associated Data. PSK only requires a single 425 argument. If other authentication mechanisms based on 426 certificates are used, then, files for the CPE private keys, 427 certificates and certification authority should be specified. 429 - Public Authoritative Master(s): The FQDN or IP addresses of the 430 Public Authoritative Master. It MAY correspond to the data 431 that will be set in the NS RRsets and SOA of the DNS Homenet 432 Zone. IP addresses are optional and the FQDN is sufficient. 433 To secure the binding name and IP addresses, a DNSSEC exchange 434 is required. Otherwise, the IP addresses should be entered 435 manually. 437 - Registered Homenet Domain: The domain name the Public 438 Authoritative is configured for DNS slave, DNSSEC zone signing 439 and DNSSEC zone hosting. 441 Setting the DNS(SEC) Homenet Zone requires the following information. 443 - Registered Homenet Domain: The Domain Name of the zone. Multiple 444 Registered Homenet Domain may be provided. This will generate 445 the creation of multiple DNS Homenet Zones. 447 - Public Authoritative Server: The Public Authoritative Servers 448 associated to the Registered Homenet Domain. Multiple Public 449 Authoritative Server may be provided. 451 5. Synchronization between CPE and Public Authoritative Servers 453 The DNS(SEC) Homenet Reverse Zone and the DNS Homenet Zone can be 454 updated either with DNS update [RFC2136] or using a master / slave 455 synchronization. The master / slave mechanism is preferred as it 456 better scales and avoids DoS attacks: First the master notifies the 457 slave the zone must be updated, and leaves the slave to proceed to 458 the update when possible. Then, the NOTIFY message sent by the 459 master is a small packet that is less likely to load the slave. At 460 last, the AXFR query performed by the slave is a small packet sent 461 over TCP (section 4.2 [RFC5936]) which makes unlikely the slave to 462 perform reflection attacks with a forged NOTIFY. On the other hand, 463 DNS updates can use UDP, packets require more processing then a 464 NOTIFY, and they do not provide the server the opportunity to post- 465 pone the update. 467 This document recommends the use of a master / slave mechanism 468 instead of the use of nsupdates. This section details the master / 469 slave mechanism. 471 5.1. Synchronization with a Hidden Master 473 Uploading and dynamically updating the zone file on the Public 474 Authoritative Name Server Set can be seen as zone provisioning 475 between the CPE (Hidden Master) and the Public Authoritative Name 476 Server Set (Slave Server). This can be handled either in band or out 477 of band. 479 The Public Authoritative Name Server Set is configured as a slave for 480 the Homenet Domain Name. This slave configuration has been 481 previously agreed between the end user and the provider of the Public 482 Authoritative Servers. In order to set the master/ slave 483 architecture, the CPE acts as a Hidden Master Server, which is a 484 regular Authoritative DNS(SEC) Server listening on the WAN interface. 486 The Hidden Master Server is expected to accept SOA [RFC1033], AXFR 487 [RFC1034], and IXFR [RFC1995] queries from its configured slave DNS 488 servers. The Hidden Master Server SHOULD send NOTIFY messages 489 [RFC1996] in order to update Public DNS server zones as updates 490 occur. Because, DNS Homenet Zones are likely to be small, CPE MUST 491 implement AXFR and SHOULD implement IXFR. 493 Hidden Master Server differs from a regular authoritative server for 494 the home network by: 496 - Interface Binding: the Hidden Master Server listens on the WAN 497 Interface, whereas a regular authoritative server for the home 498 network would listen on the home network interface. 500 - Limited exchanges: the purpose of the Hidden Master Server is to 501 synchronizes with the Public Authoritative Name Server Set, not 502 to serve zone. As a result, exchanges are performed with 503 specific nodes (the Public Authoritative Servers). Then 504 exchange types are limited. The only legitimate exchanges are: 505 NOTIFY initiated by the Hidden Master and IXFR or AXFR 506 exchanges initiated by the Public Authoritative Name Server 507 Set. On the other hand regular authoritative servers would 508 respond any hosts on the home network, and any DNS(SEC) query 509 would be considered. The CPE SHOULD filter IXFR/AXFR traffic 510 and drop traffic not initiated by the Public Authoritative 511 Server. The CPE MUST listen for DNS on TCP and UDP and at 512 least allow SOA lookups to the DNS Homenet Zone. 514 5.2. Securing Synchronization 516 Exchange between the Public Servers and the CPE MUST be secured, at 517 least for integrity protection and for authentication. This is the 518 case whatever mechanism is used between the CPE and the Public 519 Authoritative Name Server Set. 521 TSIG [RFC2845] or SIG(0) [RFC2931] can be used to secure the DNS 522 communications between the CPE and the Public DNS(SEC) Servers. TSIG 523 uses a symmetric key which can be managed by TKEY [RFC2930]. 524 Management of the key involved in SIG(0) is performed through zone 525 updates. How to roll the keys with SIG(0) is out-of-scope of this 526 document. The advantage of these mechanisms is that they are only 527 associated with the DNS application. Not relying on shared libraries 528 ease testing and integration. On the other hand, using TSIG, TKEY or 529 SIG(0) requires that these mechanisms to be implemented on the 530 DNS(SEC) Server's implementation running on the CPE, which adds 531 codes. Another disadvantage is that TKEY does not provides 532 authentication mechanism. 534 Protocols like TLS [RFC5246] / DTLS [RFC6347] can be used to secure 535 the transactions between the Public Authoritative Servers and the 536 CPE. The advantage of TLS/DTLS is that this technology is widely 537 deployed, and most of the boxes already embeds a TLS/DTLS libraries, 538 eventually taking advantage of hardware acceleration. Then TLS/DTLS 539 provides authentication facilities and can use certificates to 540 authenticate the Public Authoritative Server and the CPE. On the 541 other hand, using TLS/DTLS requires to integrate DNS exchange over 542 TLS/DTLS, as well as a new service port. This is why we do not 543 recommend this option. 545 IPsec [RFC4301] IKEv2 [RFC7296] can also be used to secure the 546 transactions between the CPE and the Public Authoritative Servers. 547 Similarly to TLS/DTLS, most CPE already embeds a IPsec stack, and 548 IKEv2 provides multiple authentications possibilities with its EAP 549 framework. In addition, IPsec can be used to protect the DNS 550 exchanges between the CPE and the Public Authoritative Servers 551 without any modifications of the DNS Servers or client. DNS 552 integration over IPsec only requires an additional security policy in 553 the Security Policy Database. One disadvantage of IPsec is that it 554 hardly goes through NATs and firewalls. However, in our case, the 555 CPE is connected to the Internet, and IPsec communication between the 556 CPE and Public Authoritative Server SHOULD NOT be impacted by middle 557 boxes. 559 As mentioned above, TSIG, IPsec and TLS/DTLS may be used to secure 560 transactions between the CPE and the Public Authentication Servers. 561 The CPE and Public Authoritative Server SHOULD implement TSIG and 562 IPsec. 564 How the PSK can be used by any of the TSIG, TLS/DTLS or IPsec 565 protocols. Authentication based on certificates implies a mutual 566 authentication and thus requires the CPE to manage a private key, a 567 public key or certificates as well as Certificate Authorities. This 568 adds complexity to the configuration especially on the CPE side. For 569 this reason, we recommend that CPE MAY use PSK or certificate base 570 authentication and that Public Authentication Servers MUST support 571 PSK and certificate based authentication. 573 5.3. CPE Security Policies 575 This section details security policies related to the Hidden Master / 576 Slave synchronization. 578 The Hidden Master, as described in this document SHOULD drop any 579 queries from the home network. This can be performed with port 580 binding and/or firewall rules. 582 The Hidden Master SHOULD drop on the WAN interface any DNS queries 583 that is not issued from the Public Authoritative Server Name Server 584 Set. 586 The Hidden Master SHOULD drop any outgoing packets other than DNS 587 NOTIFY query, SOA response, IXFR response or AXFR responses. 589 The Hidden Master SHOULD drop any incoming packets other than DNS 590 NOTIFY response, SOA query, IXFR query or AXFR query. 592 The Hidden Master SHOULD drop any non protected IXFR or AXFR 593 exchange. This depends how the synchronization is secured. 595 6. DNSSEC compliant Homenet Architecture 597 [RFC7368] in Section 3.7.3 recommends DNSSEC to be deployed on the 598 both the authoritative server and the resolver. The resolver side is 599 out of scope of this document, and only the authoritative part is 600 considered. 602 Deploying DNSSEC requires signing the zone and configuring a secure 603 delegation. As described in Section 4.1, signing can be performed by 604 the CPE or by the Public Authoritative Servers. Section 6.1 details 605 the implications of these two alternatives. Similarly, the secure 606 delegation can be performed by the CPE or by the Public Authoritative 607 Servers. Section 6.2 discusses these two alternatives. 609 6.1. Zone Signing 611 This section discusses the pros and cons when zone signing is 612 performed by the CPE or by the Public Authoritative Servers. It is 613 recommended to sign the zone by the CPE unless there is a strong 614 argument against it, like a CPE that is not able to sign the zone. 615 In that case zone signing may be performed by the Public 616 Authoritative Servers on behalf of the CPE. 618 Reasons for signing the zone by the CPE are: 620 - 1: Keeping the Homenet Zone and the Public Zone equals to securely 621 optimize DNS resolution. As the Public Zone is signed with 622 DNSSEC, RRsets are authenticated and thus DNS responses can be 623 validated even though they are not provided by the 624 authoritative server. This provides the CPE the ability to 625 respond on behalf of the Public Authoritative Master. This 626 could be useful for example if, in the future, the CPE could 627 announce to the home network that the CPE can act a a local 628 authoritative master or equivalent for the Homenet Zone. 629 Currently the CPE is not expected to receive authoritative DNS 630 queries as its IP address is not mentioned in the Public Zone. 631 On the other hand most CPE host a resolving function, and could 632 be configured to perform a local lookup to the Homenet Zone 633 instead of initiating a DNS exchange with the Public 634 Authoritative Master. Note that outsourcing the zone signing 635 operation requires that all DNSSEC queries be cached to perform 636 a local lookup, otherwise a resolution with the Public 637 Authoritative Master is performed. 639 - 2: Keeping the Homenet Zone and the Public Zone equals to securely 640 address the connectivity disruption independence exposed in 641 [RFC7368] section 4.4.1 and 3.7.5. As local lookup is 642 possible, in case of network disruption, communications within 643 the home network can still rely on the DNSSEC service. Note 644 that outsourcing the zone signing operation does not address 645 connectivity disruption independence with DNSSEC. Instead a 646 fall back to DNS resolution occurs as the local Homenet Zone is 647 not signed. 649 - 3: Keeping the Homenet Zone and the Public Zone equals to 650 guarantee coherence between DNS(SEC) responses. Using a unique 651 zone is one way to guarantee uniqueness of the responses among 652 servers and places. Issues generated by different views are 653 discussed in more details in Section 7. 655 - 2: Privacy and Integrity of the DNS Zone are better guaranteed. 656 When the Zone is signed by the CPE, it makes modification of 657 the DNS data -- for example for flow redirection -- not 658 possible. As a result, signing the Homenet Zone by the CPE 659 provides better protection for the end user privacy. 661 Reasons for signing the zone by the Public Authoritative Servers are: 663 - 1: The CPE is not able to sign the zone, most likely because its 664 firmware does not make it possible. However the reason is 665 expected to be less and less valid over time. 667 - 2: Outsourcing DNSSEC management operations. Management 668 operations involve key-roll over which can be done 669 automatically by the CPE and transparently for the end user. 670 As result avoiding DNSSEC management is mostly motivated by bad 671 software implementations. 673 - 3: Reducing the impact of CPE replacement on the Public Zone. 674 Unless the CPE private keys are backuped, CPE replacement 675 results in a emergency key roll over. This can be mitigated 676 also by using relatively small TTLs. 678 - 4: Reducing configuration impacts on the end user. Unless there 679 are some zero configuration mechanisms to provide credentials 680 between the new CPE and the Public Authoritative Name Server 681 Sets. Authentications to Public Authoritative Name Server Set 682 should be re-configured. As CPE replacement is not expected to 683 happen regularly, end users may not be at ease with such 684 configuration settings. However, mechanisms as described in 685 [I-D.ietf-homenet-naming-architecture-dhc-options] use DHCP 686 Options to outsource the configuration and avoid this issue. 688 - 5: Public Authoritative Servers are more likely to handle securely 689 private keys than the CPE. However, having all private 690 information at one place may also balance that risk. 692 6.2. Secure Delegation 694 The secure delegation is set if the DS RRset is properly set in the 695 parent zone. Secure delegation can be performed by the CPE or the 696 Public Authoritative Servers. 698 The DS RRset can be updated manually by the CPE or the Public 699 Authoritative Servers. This can be used then with nsupdate for 700 example bu requires the CPE or the Public Authoritative Server to be 701 authenticated by the Parent Zone Server. Such a trust channel 702 between the CPE and the Parent Zone server may be hard to maintain, 703 and thus may be easier to establish with the Public Authoritative 704 Server. On the other hand, [RFC7344] may mitigate such issues. 706 7. Handling Different Views 708 The DNS Homenet Zone provides information about the home network and 709 some user may be tempted to have different information regarding the 710 origin of the DNS query. More specifically, some users may be 711 tempted to provide a different view for DNS queries originating from 712 the home network and for DNS queries coming from the wild Internet. 713 Each view can be associated to a dedicated Homenet Zone. Note that 714 this document does not specify how DNS queries coming from the home 715 network are addressed to the DNS(SEC) Homenet Zone. This could be 716 done via the DNS resolver hosted on the CPE for example. 718 This section is not normative. Section 7.1 expose different reasons 719 that result in different views, Section 7.2 briefly describes the 720 consequences of having distinct views, and Section 7.3 provides 721 guidance to avoid this situation. 723 7.1. Motivations 725 The main motivation to handle different views is to provide different 726 information depending on the location the DNS query is emitted. Here 727 are a few motivations for doing so: 729 - 1: An end user may want to have services not published on the 730 Internet. Services like the CPE administration interface that 731 provides the GUI to administrate your CPE may not be published 732 on the Internet. Similarly services like the mapper that 733 registers the devices of your home network may not be published 734 on the Internet. In both case, these services should only be 735 known/used by the network administrator. To restrict the 736 access of such services, the home network administrator may 737 chose to publish these information only within the home 738 network, where it may suppose users are more trustable then on 739 the Internet. Even though, this assumption may not be valid, 740 at least, this reduces the surface of attack. 742 - 2: Services within the home network may be reachable using non 743 global IP addresses. IPv4 and NAT may be one reason. On the 744 other hand IPv6 may favor link-local or site-local IP 745 addresses. These IP addresses are not significant outside the 746 boundaries of the home network. As a result, they may be 747 published in the home network view, and should not be published 748 in the Internet. 750 - 3: If the CPE does not sign the Homenet Zone and outsource the 751 signing process, the two views are at least different since, 752 one is protected with DNSSEC whereas the other is not. 754 7.2. Consequences 756 Enabling different views leads to a non-coherent naming system. 757 Basically, depending on where you are some services will not be 758 available. This may be especially inconvenient with devices with 759 multiple interfaces that are attached both to the Internet via a 760 3G/4G interface and to the home network via a WLAN interface. 762 Regarding local-scope IP addresses, such device may end up with poor 763 connectivity. Suppose, for example, the DNS resolution is performed 764 via the WLAN interface attached to the CPE, the response provides 765 local-scope IP addresses and the communication is initiated on the 766 3G/4G interface. Communications with local-scope addresses will be 767 unreachable on the Internet, thus aborting the communication. The 768 same situation occurs if a device is flip / flopping between various 769 WLAN networks. 771 Regarding DNSSEC, devices with multiple interfaces will have 772 difficulties to secure the naming resolution as responses emitted 773 from the home network may not be signed. 775 For devices with all its interfaces attached to a single 776 administrative domain, that is to say the home network or the 777 Internet. Incoherence between DNS responses may also happen if the 778 device is able to perform DNS resolutions. DNS resolutions performed 779 via the CPE resolver may be different then those performed over the 780 Internet. 782 7.3. Guidance and Recommendations 784 As exposed in Section 7.2, it is recommended to avoid different 785 views. If network administrators chose to implement multiple views, 786 impacts on devices' resolution should be evaluated. 788 A consequence the DNS(SEC) Homenet Zone is expected to be the exact 789 copy of the DNS(SEC) Public Zone. As a result, services that are not 790 expected to be published on the Internet should not be part of the 791 DNS(SEC) Homenet Zone, local-scope address should not be part of the 792 DNS(SE) Homenet Zone, and when possible, the CPE should sign the 793 DNSSEC Homenet Zone. 795 The DNS(SEC) Homenet Zone is expected to host public information. It 796 is not to the DNS service to define local home networks boundaries. 797 Instead, local scope information is expected to be provided to the 798 home network using local scope naming services. mDNS [RFC6762] DNS-SD 799 [RFC6763] are one of these services. Currently mDNS is limited to a 800 single link network. However, future protocols are expected to 801 leverage this constraint as pointed out in 802 [I-D.ietf-dnssd-requirements]. 804 8. Reverse Zone 806 Most of the description considered the DNS Homenet Zone as the non- 807 Reverse Zone. This section is focused on the Reverse Zone. 809 First, all considerations for the DNS Homenet Zone apply to the 810 Reverse Homenet Zone. The main difference between the Reverse DNS 811 Homenet Zone and the DNS Homenet Zone is that the parent zone of the 812 Reverse Homenet Zone is most likely managed by the ISP. As the ISP 813 also provides the IP prefix to the CPE, it may be able to 814 authenticate the CPE. If the Reverse Public Authoritative Name 815 Server Set is managed by the ISP, credentials to authenticate the CPE 816 for the zone synchronization may be set automatically and 817 transparently to the end user. 818 [I-D.ietf-homenet-naming-architecture-dhc-options] describes how 819 automatic configuration may be performed. 821 With IPv6, the domain space for IP address is so large, that reverse 822 zone may be confronted to a scalability issue. How to reverse zone 823 is generated is out of scope of this document. 824 [I-D.howard-dnsop-ip6rdns] provides guidance on how to address the 825 scalability issue. 827 9. Privacy Considerations 829 Outsourcing the DNS Authoritative service from the CPE to a third 830 entity comes with a a few privacy related concerns. 832 First the DNS Homenet Zone contains a full description of the 833 services hosted in the network. These services may not be expected 834 to be publicly shared although their names remains accessible though 835 the Internet. Even though DNS makes information public, the DNS does 836 not expect to make the complete list of service public. In fact, 837 making information public still requires the key (or FQDN) of each 838 service to be known by the resolver in order to retrieve information 839 of the services. More specifically, making mywebsite.example.com 840 public in the DNS, is not sufficient to make resolvers aware of the 841 existence web site. 843 In order to prevent the complete DN(SEC) Homenet Zone to be published 844 on the Internet, one should prevent AXFR queries on the Public 845 Authoritative Masters. Similarly, to avoid zone-walking one should 846 prefer NSEC3 [RFC5155] over NSEC [RFC4034]. 848 When the DNS Homenet Zone is outsourced the end user must be aware 849 that it provides a complete description of the services available on 850 the home network. More specifically, names usually provides a clear 851 indication of the service and eventually the device, by as the DNS 852 Homenet Zone contains the IP addresses associated to the service, 853 they limit the scope of the scan. 855 In addition to the DNS Homenet Zone, the third party can also monitor 856 the traffic associated to the DNS Homenet Zone. This traffic may 857 provide indication of the services you use, how and when you use 858 these services. Although, cache may alter this information inside 859 the home network, it is likely that outside your home network this 860 information will not be cached. 862 10. Security Considerations 864 The Homenet Naming Architecture described in this document solves 865 exposing the CPE's DNS service as a DoS attack vector. 867 10.1. Names are less secure than IP addresses 869 This document describes how an End User can make his services and 870 devices from his home network reachable on the Internet with Names 871 rather than IP addresses. This exposes the home network to attackers 872 since names are expected to provide less randomness than IP 873 addresses. The naming delegation protects the End User's privacy by 874 not providing the complete zone of the home network to the ISP. 875 However, using the DNS with names for the home network exposes the 876 home network and its components to dictionary attacks. In fact, with 877 IP addresses, the Interface Identifier is 64 bit length leading to 878 2^64 possibilities for a given subnetwork. This is not to mention 879 that the subnet prefix is also of 64 bit length, thus providing 880 another 2^64 possibilities. On the other hand, names used either for 881 the home network domain or for the devices present less randomness 882 (livebox, router, printer, nicolas, jennifer, ...) and thus exposes 883 the devices to dictionary attacks. 885 10.2. Names are less volatile than IP addresses 887 IP addresses may be used to locate a device, a host or a Service. 888 However, home networks are not expected to be assigned the same 889 Prefix over time. As a result observing IP addresses provides some 890 ephemeral information about who is accessing the service. On the 891 other hand, Names are not expected to be as volatile as IP addresses. 892 As a result, logging Names, over time, may be more valuable that 893 logging IP addresses, especially to profile End User's 894 characteristics. 896 PTR provides a way to bind an IP address to a Name. In that sense 897 responding to PTR DNS queries may affect the End User's Privacy. For 898 that reason we recommend that End Users may choose to respond or not 899 to PTR DNS queries and may return a NXDOMAIN response. 901 11. IANA Considerations 903 This document has no actions for IANA. 905 12. Acknowledgment 907 The authors wish to thank Philippe Lemordant for its contributions on 908 the early versions of the draft, Ole Troan for pointing out issues 909 with the IPv6 routed home concept and placing the scope of this 910 document in a wider picture, Mark Townsley for encouragement and 911 injecting a healthy debate on the merits of the idea, Ulrik de Bie 912 for providing alternative solutions, Paul Mockapetris, Christian 913 Jacquenet, Francis Dupont and Ludovic Eschard for their remarks on 914 CPE and low power devices, Olafur Gudmundsson for clarifying DNSSEC 915 capabilities of small devices, Simon Kelley for its feedback as 916 dnsmasq implementer. Andrew Sullivan, Mark Andrew, Ted Lemon, Mikael 917 Abrahamson and Michael Richardson, Ray Bellis for their feed backs on 918 handling different views as well as clarifying the impact of 919 outsourcing the zone signing operation outside the CPE. 921 13. References 923 13.1. Normative References 925 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 926 STD 13, RFC 1034, November 1987. 928 [RFC1035] Mockapetris, P., "Domain names - implementation and 929 specification", STD 13, RFC 1035, November 1987. 931 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 932 August 1996. 934 [RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone 935 Changes (DNS NOTIFY)", RFC 1996, August 1996. 937 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 938 Requirement Levels", BCP 14, RFC 2119, March 1997. 940 [RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound, 941 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 942 RFC 2136, April 1997. 944 [RFC2142] Crocker, D., "MAILBOX NAMES FOR COMMON SERVICES, ROLES AND 945 FUNCTIONS", RFC 2142, May 1997. 947 [RFC2308] Andrews, M., "Negative Caching of DNS Queries (DNS 948 NCACHE)", RFC 2308, March 1998. 950 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake, D., and B. 951 Wellington, "Secret Key Transaction Authentication for DNS 952 (TSIG)", RFC 2845, May 2000. 954 [RFC2930] Eastlake, D., "Secret Key Establishment for DNS (TKEY 955 RR)", RFC 2930, September 2000. 957 [RFC2931] Eastlake, D., "DNS Request and Transaction Signatures ( 958 SIG(0)s)", RFC 2931, September 2000. 960 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 961 Rose, "Resource Records for the DNS Security Extensions", 962 RFC 4034, March 2005. 964 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 965 Internet Protocol", RFC 4301, December 2005. 967 [RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS 968 Security (DNSSEC) Hashed Authenticated Denial of 969 Existence", RFC 5155, March 2008. 971 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 972 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 974 [RFC5936] Lewis, E. and A. Hoenes, "DNS Zone Transfer Protocol 975 (AXFR)", RFC 5936, June 2010. 977 [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer 978 Security Version 1.2", RFC 6347, January 2012. 980 [RFC6644] Evans, D., Droms, R., and S. Jiang, "Rebind Capability in 981 DHCPv6 Reconfigure Messages", RFC 6644, July 2012. 983 [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, 984 February 2013. 986 [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service 987 Discovery", RFC 6763, February 2013. 989 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 990 Kivinen, "Internet Key Exchange Protocol Version 2 991 (IKEv2)", STD 79, RFC 7296, October 2014. 993 13.2. Informational References 995 [I-D.howard-dnsop-ip6rdns] 996 Howard, L., "Reverse DNS in IPv6 for Internet Service 997 Providers", draft-howard-dnsop-ip6rdns-00 (work in 998 progress), June 2014. 1000 [I-D.ietf-dnssd-requirements] 1001 Lynn, K., Cheshire, S., Blanchet, M., and D. Migault, 1002 "Requirements for Scalable DNS-SD/mDNS Extensions", draft- 1003 ietf-dnssd-requirements-04 (work in progress), October 1004 2014. 1006 [I-D.ietf-homenet-naming-architecture-dhc-options] 1007 Migault, D., Cloetens, W., Griffiths, C., and R. Weber, 1008 "DHCP Options for Homenet Naming Architecture", draft- 1009 ietf-homenet-naming-architecture-dhc-options-00 (work in 1010 progress), September 2014. 1012 [RFC1033] Lottor, M., "Domain administrators operations guide", RFC 1013 1033, November 1987. 1015 [RFC7344] Kumari, W., Gudmundsson, O., and G. Barwood, "Automating 1016 DNSSEC Delegation Trust Maintenance", RFC 7344, September 1017 2014. 1019 [RFC7368] Chown, T., Arkko, J., Brandt, A., Troan, O., and J. Weil, 1020 "IPv6 Home Networking Architecture Principles", RFC 7368, 1021 October 2014. 1023 Appendix A. Document Change Log 1025 [RFC Editor: This section is to be removed before publication] 1027 -05: 1029 *Clarifying on handling different views: 1031 - 1: How the CPE may be involved in the resolution and responds 1032 without necessarily requesting the Public Masters (and 1033 eventually the Hidden Master) 1035 - 2: How to handle local scope resolution that is link-local, site- 1036 local and NAT IP addresses as well as Private domain names that 1037 the administrator does not want to publish outside the home 1038 network. 1040 Adding a Privacy Considerations Section 1042 Clarification on pro/cons outsourcing zone-signing 1043 Documenting how to handle reverse zones 1045 Adding reference to RFC 2308 1047 -04: 1049 *Clarifications on zone signing 1051 *Rewording 1053 *Adding section on different views 1055 *architecture clarifications 1057 -03: 1059 *Simon's comments taken into consideration 1061 *Adding SOA, PTR considerations 1063 *Removing DNSSEC performance paragraphs on low power devices 1065 *Adding SIG(0) as a mechanism for authenticating the servers 1067 *Goals clarification: the architecture described in the document 1) 1068 does not describe new protocols, and 2) can be adapted to specific 1069 cases for advance users. 1071 -02: 1073 *remove interfaces: "Public Authoritative Server Naming Interface" is 1074 replaced by "Public Authoritative Master(s)". "Public Authoritative 1075 Server Management Interface" is replaced by "Public Authoritative 1076 Name Server Set". 1078 -01.3: 1080 *remove the authoritative / resolver services of the CPE. 1081 Implementation dependent 1083 *remove interactions with mdns and dhcp. Implementation dependent. 1085 *remove considerations on low powered devices 1087 *remove position toward homenet arch 1089 *remove problem statement section 1090 -01.2: 1092 * add a CPE description to show that the architecture can fit CPEs 1094 * specification of the architecture for very low powered devices. 1096 * integrate mDNS and DHCP interactions with the Homenet Naming 1097 Architecture. 1099 * Restructuring the draft. 1) We start from the homenet-arch draft to 1100 derive a Naming Architecture, then 2) we show why CPE need mechanisms 1101 that do not expose them to the Internet, 3) we describe the 1102 mechanisms. 1104 * I remove the terminology and expose it in the figures A and B. 1106 * remove the Front End Homenet Naming Architecture to Homenet Naming 1108 -01: 1110 * Added C. Griffiths as co-author. 1112 * Updated section 5.4 and other sections of draft to update section 1113 on Hidden Master / Slave functions with CPE as Hidden Master/Homenet 1114 Server. 1116 * For next version, address functions of MDNS within Homenet Lan and 1117 publishing details northbound via Hidden Master. 1119 -00: First version published. 1121 Authors' Addresses 1123 Daniel Migault 1124 Ericsson 1125 8400 boulevard Decarie 1126 Montreal, QC H4P 2N2 1127 Canada 1129 Email: mglt.ietf@gmail.com 1130 Wouter Cloetens 1131 SoftAtHome 1132 vaartdijk 3 701 1133 3018 Wijgmaal 1134 Belgium 1136 Email: wouter.cloetens@softathome.com 1138 Chris Griffiths 1139 Dyn 1140 150 Dow Street 1141 Manchester, NH 03101 1142 US 1144 Email: cgriffiths@dyn.com 1145 URI: http://dyn.com 1147 Ralf Weber 1148 Nominum 1149 2000 Seaport Blvd #400 1150 Redwood City, CA 94063 1151 US 1153 Email: ralf.weber@nominum.com 1154 URI: http://www.nominum.com