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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force T. Chown 3 Internet-Draft Jisc 4 Obsoletes: 6434 (if approved) J. Loughney 5 Intended status: Best Current Practice Intel 6 Expires: August 10, 2018 T. Winters 7 UNH-IOL 8 February 6, 2018 10 IPv6 Node Requirements 11 draft-ietf-6man-rfc6434-bis-03 13 Abstract 15 This document defines requirements for IPv6 nodes. It is expected 16 that IPv6 will be deployed in a wide range of devices and situations. 17 Specifying the requirements for IPv6 nodes allows IPv6 to function 18 well and interoperate in a large number of situations and 19 deployments. 21 This document obsoletes RFC 6434, and in turn RFC 4294. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on August 10, 2018. 40 Copyright Notice 42 Copyright (c) 2018 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 58 1.1. Scope of This Document . . . . . . . . . . . . . . . . . 4 59 1.2. Description of IPv6 Nodes . . . . . . . . . . . . . . . . 5 60 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5 61 3. Abbreviations Used in This Document . . . . . . . . . . . . . 5 62 4. Sub-IP Layer . . . . . . . . . . . . . . . . . . . . . . . . 5 63 5. IP Layer . . . . . . . . . . . . . . . . . . . . . . . . . . 6 64 5.1. Internet Protocol Version 6 - RFC 8200 . . . . . . . . . 6 65 5.2. Support for IPv6 Extension Headers . . . . . . . . . . . 7 66 5.3. Protecting a node from excessive EH options . . . . . . . 8 67 5.4. Neighbor Discovery for IPv6 - RFC 4861 . . . . . . . . . 9 68 5.5. SEcure Neighbor Discovery (SEND) - RFC 3971 . . . . . . . 10 69 5.6. IPv6 Router Advertisement Flags Option - RFC 5175 . . . . 10 70 5.7. Path MTU Discovery and Packet Size . . . . . . . . . . . 11 71 5.7.1. Path MTU Discovery - RFC 8201 . . . . . . . . . . . . 11 72 5.7.2. Minimum MTU considerations . . . . . . . . . . . . . 11 73 5.8. ICMP for the Internet Protocol Version 6 (IPv6) - RFC 74 4443 . . . . . . . . . . . . . . . . . . . . . . . . . . 11 75 5.9. Default Router Preferences and More-Specific Routes - RFC 76 4191 . . . . . . . . . . . . . . . . . . . . . . . . . . 11 77 5.10. First-Hop Router Selection - RFC 8028 . . . . . . . . . . 12 78 5.11. Multicast Listener Discovery (MLD) for IPv6 - RFC 3810 . 12 79 5.12. Explicit Congestion Notification (ECN) - RFC 3168 . . . . 12 80 6. Addressing and Address Configuration . . . . . . . . . . . . 12 81 6.1. IP Version 6 Addressing Architecture - RFC 4291 . . . . . 12 82 6.2. Host Address Availability Recommendations . . . . . . . . 13 83 6.3. IPv6 Stateless Address Autoconfiguration - RFC 4862 . . . 13 84 6.4. Privacy Extensions for Address Configuration in IPv6 - 85 RFC 4941 . . . . . . . . . . . . . . . . . . . . . . . . 14 86 6.5. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 . 15 87 6.6. Default Address Selection for IPv6 - RFC 6724 . . . . . . 15 88 7. DNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 89 8. Configuring Non-Address Information . . . . . . . . . . . . . 16 90 8.1. DHCP for Other Configuration Information . . . . . . . . 16 91 8.2. Router Advertisements and Default Gateway . . . . . . . . 16 92 8.3. IPv6 Router Advertisement Options for DNS 93 Configuration - RFC 8106 . . . . . . . . . . . . . . . . 16 94 8.4. DHCP Options versus Router Advertisement Options for Host 95 Configuration . . . . . . . . . . . . . . . . . . . . . . 17 96 9. Service Discovery Protocols . . . . . . . . . . . . . . . . . 17 97 10. IPv4 Support and Transition . . . . . . . . . . . . . . . . . 17 98 10.1. Transition Mechanisms . . . . . . . . . . . . . . . . . 18 99 10.1.1. Basic Transition Mechanisms for IPv6 Hosts and 100 Routers - RFC 4213 . . . . . . . . . . . . . . . . . 18 101 11. Application Support . . . . . . . . . . . . . . . . . . . . . 18 102 11.1. Textual Representation of IPv6 Addresses - RFC 5952 . . 18 103 11.2. Application Programming Interfaces (APIs) . . . . . . . 18 104 12. Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . 19 105 13. Security . . . . . . . . . . . . . . . . . . . . . . . . . . 19 106 13.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 20 107 13.2. Transforms and Algorithms . . . . . . . . . . . . . . . 21 108 14. Router-Specific Functionality . . . . . . . . . . . . . . . . 21 109 14.1. IPv6 Router Alert Option - RFC 2711 . . . . . . . . . . 21 110 14.2. Neighbor Discovery for IPv6 - RFC 4861 . . . . . . . . . 21 111 14.3. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 . 22 112 14.4. IPv6 Prefix Length Recommendation for Forwarding - BCP 113 198 . . . . . . . . . . . . . . . . . . . . . . . . . . 22 114 15. Constrained Devices . . . . . . . . . . . . . . . . . . . . . 22 115 16. Network Management . . . . . . . . . . . . . . . . . . . . . 23 116 16.1. Management Information Base (MIB) Modules . . . . . . . 23 117 16.1.1. IP Forwarding Table MIB . . . . . . . . . . . . . . 23 118 16.1.2. Management Information Base for the Internet 119 Protocol (IP) . . . . . . . . . . . . . . . . . . . 23 120 16.2. YANG Data Models . . . . . . . . . . . . . . . . . . . . 23 121 16.2.1. IP Management YANG Model . . . . . . . . . . . . . . 23 122 16.2.2. System Management YANG Model . . . . . . . . . . . . 24 123 16.2.3. System Management YANG Model . . . . . . . . . . . . 24 124 17. Security Considerations . . . . . . . . . . . . . . . . . . . 24 125 18. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 126 19. Authors and Acknowledgments . . . . . . . . . . . . . . . . . 24 127 19.1. Authors and Acknowledgments (Current Document) . . . . . 24 128 19.2. Authors and Acknowledgments from RFC 6434 . . . . . . . 24 129 19.3. Authors and Acknowledgments from RFC 4294 . . . . . . . 24 130 20. Appendix: Changes from RFC 6434 . . . . . . . . . . . . . . . 26 131 21. Appendix: Changes from RFC 4294 . . . . . . . . . . . . . . . 27 132 22. References . . . . . . . . . . . . . . . . . . . . . . . . . 29 133 22.1. Normative References . . . . . . . . . . . . . . . . . . 29 134 22.2. Informative References . . . . . . . . . . . . . . . . . 35 135 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 40 137 1. Introduction 139 This document defines common functionality required by both IPv6 140 hosts and routers. Many IPv6 nodes will implement optional or 141 additional features, but this document collects and summarizes 142 requirements from other published Standards Track documents in one 143 place. 145 This document tries to avoid discussion of protocol details and 146 references RFCs for this purpose. This document is intended to be an 147 applicability statement and to provide guidance as to which IPv6 148 specifications should be implemented in the general case and which 149 specifications may be of interest to specific deployment scenarios. 150 This document does not update any individual protocol document RFCs. 152 Although this document points to different specifications, it should 153 be noted that in many cases, the granularity of a particular 154 requirement will be smaller than a single specification, as many 155 specifications define multiple, independent pieces, some of which may 156 not be mandatory. In addition, most specifications define both 157 client and server behavior in the same specification, while many 158 implementations will be focused on only one of those roles. 160 This document defines a minimal level of requirement needed for a 161 device to provide useful internet service and considers a broad range 162 of device types and deployment scenarios. Because of the wide range 163 of deployment scenarios, the minimal requirements specified in this 164 document may not be sufficient for all deployment scenarios. It is 165 perfectly reasonable (and indeed expected) for other profiles to 166 define additional or stricter requirements appropriate for specific 167 usage and deployment environments. For example, this document does 168 not mandate that all clients support DHCP, but some deployment 169 scenarios may deem it appropriate to make such a requirement. For 170 example, government agencies in the USA have defined profiles for 171 specialized requirements for IPv6 in target environments (see 172 [USGv6]). 174 As it is not always possible for an implementer to know the exact 175 usage of IPv6 in a node, an overriding requirement for IPv6 nodes is 176 that they should adhere to Jon Postel's Robustness Principle: "Be 177 conservative in what you do, be liberal in what you accept from 178 others" [RFC0793]. 180 1.1. Scope of This Document 182 IPv6 covers many specifications. It is intended that IPv6 will be 183 deployed in many different situations and environments. Therefore, 184 it is important to develop requirements for IPv6 nodes to ensure 185 interoperability. 187 This document assumes that all IPv6 nodes meet the minimum 188 requirements specified here. 190 1.2. Description of IPv6 Nodes 192 From the Internet Protocol, Version 6 (IPv6) Specification [RFC8200], 193 we have the following definitions: 195 IPv6 node - a device that implements IPv6. 196 IPv6 router - a node that forwards IPv6 packets not explicitly 197 addressed to itself. 198 IPv6 host - any node that is not a router. 200 2. Requirements Language 202 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 203 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 204 document are to be interpreted as described in RFC 2119 [RFC2119]. 206 3. Abbreviations Used in This Document 208 AH Authentication Header 209 DAD Duplicate Address Detection 210 ESP Encapsulating Security Payload 211 ICMP Internet Control Message Protocol 212 IKE Internet Key Exchange 213 MIB Management Information Base 214 MLD Multicast Listener Discovery 215 MTU Maximum Transmission Unit 216 NA Neighbor Advertisement 217 NBMA Non-Broadcast Multiple Access 218 ND Neighbor Discovery 219 NS Neighbor Solicitation 220 NUD Neighbor Unreachability Detection 221 PPP Point-to-Point Protocol 223 4. Sub-IP Layer 225 An IPv6 node must include support for one or more IPv6 link-layer 226 specifications. Which link-layer specifications an implementation 227 should include will depend upon what link-layers are supported by the 228 hardware available on the system. It is possible for a conformant 229 IPv6 node to support IPv6 on some of its interfaces and not on 230 others. 232 As IPv6 is run over new layer 2 technologies, it is expected that new 233 specifications will be issued. In the following, we list some of the 234 layer 2 technologies for which an IPv6 specification has been 235 developed. It is provided for informational purposes only and may 236 not be complete. 238 - Transmission of IPv6 Packets over Ethernet Networks [RFC2464] 240 - Transmission of IPv6 Packets over Frame Relay Networks 241 Specification [RFC2590] 243 - Transmission of IPv6 Packets over IEEE 1394 Networks [RFC3146] 245 - Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP) 246 Packets over Fibre Channel [RFC4338] 248 - Transmission of IPv6 Packets over IEEE 802.15.4 Networks [RFC4944] 250 - Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE 251 802.16 Networks [RFC5121] 253 - IP version 6 over PPP [RFC5072] 255 In addition to traditional physical link-layers, it is also possible 256 to tunnel IPv6 over other protocols. Examples include: 258 - Teredo: Tunneling IPv6 over UDP through Network Address 259 Translations (NATs) [RFC4380] 261 - Section 3 of "Basic Transition Mechanisms for IPv6 Hosts and 262 Routers" [RFC4213] 264 5. IP Layer 266 5.1. Internet Protocol Version 6 - RFC 8200 268 The Internet Protocol Version 6 is specified in [RFC8200]. This 269 specification MUST be supported. 271 The node MUST follow the packet transmission rules in RFC 8200. 273 All conformant IPv6 implementations MUST be capable of sending and 274 receiving IPv6 packets; forwarding functionality MAY be supported. 275 Nodes MUST always be able to send, receive, and process fragment 276 headers. Overlapping fragments MUST be handled as described in 277 [RFC5722]. 279 [RFC6946] discusses IPv6 atomic fragments, and recommends that IPv6 280 atomic fragments are processed independently of any other fragments, 281 to protect against fragmentation-based attacks. [RFC8021] goes 282 further and recommends the deprecation of atomic fragments. Nodes 283 thus MUST NOT generate atomic fragments. 285 To mitigate a variety of potential attacks, nodes SHOULD avoid using 286 predictable fragment Identification values in Fragment Headers, as 287 discussed in [RFC7739]. 289 All nodes SHOULD support the setting and use of the IPv6 Flow Label 290 field as defined in the IPv6 Flow Label specification [RFC6437]. 291 Forwarding nodes such as routers and load distributors MUST NOT 292 depend only on Flow Label values being uniformly distributed. It is 293 RECOMMENDED that source hosts support the flow label by setting the 294 Flow Label field for all packets of a given flow to the same value 295 chosen from an approximation to a discrete uniform distribution. 297 5.2. Support for IPv6 Extension Headers 299 RFC 8200 specifies extension headers and the processing for these 300 headers. 302 Any unrecognized extension headers or options MUST be processed as 303 described in RFC 8200. Note that where Section 4 of RFC 8200 refers 304 to the action to be taken when a Next Header value in the current 305 header is not recognized by a node, that action applies whether the 306 value is an unrecognized Extension Header or an unrecognized upper 307 layer protocol (ULP). 309 An IPv6 node MUST be able to process these headers. An exception is 310 Routing Header type 0 (RH0), which was deprecated by [RFC5095] due to 311 security concerns and which MUST be treated as an unrecognized 312 routing type. 314 Further, [RFC7045] adds specific requirements for processing of 315 Extension Headers, in particular that any forwarding node along an 316 IPv6 packet's path, which forwards the packet for any reason, SHOULD 317 do so regardless of any extension headers that are present. 319 [RFC7112] discusses issues with oversized IPv6 Extension Header 320 chains, and states that when a node fragments an IPv6 datagram, it 321 MUST include the entire IPv6 Header Chain in the First Fragment. 323 As stated in RFC8200, extension headers (except for the Hop-by-Hop 324 Options header) are not processed, inserted, or deleted by any node 325 along a packet's delivery path, until the packet reaches the node (or 326 each of the set of nodes, in the case of multicast) identified in the 327 Destination Address field of the IPv6 header. 329 It should be noted that when future, new Extension Headers are 330 defined, the consistent format described in Section 4 of [RFC6564] 331 MUST be followed. 333 5.3. Protecting a node from excessive EH options 335 Per RFC 8200, end hosts are expected to process all extension 336 headers, destination options, and hop-by-hop options in a packet. 337 Given that the only limit on the number and size of extension headers 338 is the MTU, the processing of received packets could be considerable. 339 It is also conceivable that a long chain of extension headers might 340 be used as a form of denial-of-service attack. Accordingly, a host 341 may place limits on the number and sizes of extension headers and 342 options it is willing to process. 344 A host MAY limit the number of consecutive PAD1 options in 345 destination options or hop-by-hop options to seven. In this case, if 346 the more than seven consecutive PAD1 options are present the the 347 packet should be silently discarded. The rationale is that if 348 padding of eight or more bytes is required than the PADN option 349 should be used. 351 A host MAY limit number of bytes in a PADN option to be less than 352 eight. In such a case, if a PADN option is present that has a length 353 greater than seven then the packet should be silently discarded. The 354 rationale for this guideline is that the purpose of padding is for 355 alignment and eight bytes is the maximum alignment used in IPv6. 357 A host MAY disallow unknown options in destination options or hop-by- 358 hop options. This should be configurable where the default is to 359 accept unknown options and process them per [RFC8200]. If a packet 360 with unknown options is received and the host is configured to 361 disallow them, then the packet should be silently discarded. 363 A host MAY impose a limit on the maximum number of non-padding 364 options allowed in a destination options and hop-by-hop extension 365 headers. If this feature is supported the maximum number should be 366 configurable and the default value SHOULD be set to eight. The 367 limits for destination options and hop-by-hop options may be 368 separately configurable. If a packet is received and the number of 369 destination or hop-by-hop optines exceeds the limit, then the packet 370 should be silently discarded. 372 A host MAY impose a limit on the maximum length of destination 373 options or hop-by-hop options extension header. This value should be 374 configurable and the default is to accept options of any length. If 375 a packet is received and the length of destination or hop-by-hop 376 options extension header exceeds the length limit, then the packet 377 should be silently discarded. 379 5.4. Neighbor Discovery for IPv6 - RFC 4861 381 Neighbor Discovery is defined in [RFC4861]; the definition was 382 updated by [RFC5942]. Neighbor Discovery SHOULD be supported. RFC 383 4861 states: 385 Unless specified otherwise (in a document that covers operating IP 386 over a particular link type) this document applies to all link 387 types. However, because ND uses link-layer multicast for some of 388 its services, it is possible that on some link types (e.g., Non- 389 Broadcast Multi-Access (NBMA) links), alternative protocols or 390 mechanisms to implement those services will be specified (in the 391 appropriate document covering the operation of IP over a 392 particular link type). The services described in this document 393 that are not directly dependent on multicast, such as Redirects, 394 next-hop determination, Neighbor Unreachability Detection, etc., 395 are expected to be provided as specified in this document. The 396 details of how one uses ND on NBMA links are addressed in 397 [RFC2491]. 399 Some detailed analysis of Neighbor Discovery follows: 401 Router Discovery is how hosts locate routers that reside on an 402 attached link. Hosts MUST support Router Discovery functionality. 404 Prefix Discovery is how hosts discover the set of address prefixes 405 that define which destinations are on-link for an attached link. 406 Hosts MUST support Prefix Discovery. 408 Hosts MUST also implement Neighbor Unreachability Detection (NUD) for 409 all paths between hosts and neighboring nodes. NUD is not required 410 for paths between routers. However, all nodes MUST respond to 411 unicast Neighbor Solicitation (NS) messages. 413 [RFC7048] discusses NUD, in particular cases where it behaves too 414 impatiently. It states that if a node transmits more than a certain 415 number of packets, then it SHOULD use the exponential backoff of the 416 retransmit timer, up to a certain threshold point. 418 Hosts MUST support the sending of Router Solicitations and the 419 receiving of Router Advertisements. The ability to understand 420 individual Router Advertisement options is dependent on supporting 421 the functionality making use of the particular option. 423 [RFC7559] discusses packet loss resliency for Router Solicitations, 424 and requires that nodes MUST use a specific exponential backoff 425 algorithm for RS retransmissions. 427 All nodes MUST support the sending and receiving of Neighbor 428 Solicitation (NS) and Neighbor Advertisement (NA) messages. NS and 429 NA messages are required for Duplicate Address Detection (DAD). 431 Hosts SHOULD support the processing of Redirect functionality. 432 Routers MUST support the sending of Redirects, though not necessarily 433 for every individual packet (e.g., due to rate limiting). Redirects 434 are only useful on networks supporting hosts. In core networks 435 dominated by routers, Redirects are typically disabled. The sending 436 of Redirects SHOULD be disabled by default on backbone routers. They 437 MAY be enabled by default on routers intended to support hosts on 438 edge networks. 440 "IPv6 Host-to-Router Load Sharing" [RFC4311] includes additional 441 recommendations on how to select from a set of available routers. 442 [RFC4311] SHOULD be supported. 444 5.5. SEcure Neighbor Discovery (SEND) - RFC 3971 446 SEND [RFC3971] and Cryptographically Generated Addresses (CGAs) 447 [RFC3972] provide a way to secure the message exchanges of Neighbor 448 Discovery. SEND has the potential to address certain classes of 449 spoofing attacks, but it does not provide specific protection for 450 threats from off-link attackers. 452 There have been relatively few implementations of SEND in common 453 operating systems and platforms, and thus deployment experience has 454 been limited to date. 456 At this time, SEND is considered optional. Due to the complexity in 457 deploying SEND, and its heavyweight provisioning, its deployment is 458 only likely to be considered where nodes are operating in a 459 particularly strict security environment. 461 5.6. IPv6 Router Advertisement Flags Option - RFC 5175 463 Router Advertisements include an 8-bit field of single-bit Router 464 Advertisement flags. The Router Advertisement Flags Option extends 465 the number of available flag bits by 48 bits. At the time of this 466 writing, 6 of the original 8 single-bit flags have been assigned, 467 while 2 remain available for future assignment. No flags have been 468 defined that make use of the new option, and thus, strictly speaking, 469 there is no requirement to implement the option today. However, 470 implementations that are able to pass unrecognized options to a 471 higher-level entity that may be able to understand them (e.g., a 472 user-level process using a "raw socket" facility) MAY take steps to 473 handle the option in anticipation of a future usage. 475 5.7. Path MTU Discovery and Packet Size 477 5.7.1. Path MTU Discovery - RFC 8201 479 "Path MTU Discovery for IP version 6" [RFC8201] SHOULD be supported. 480 From [RFC8200]: 482 It is strongly recommended that IPv6 nodes implement Path MTU 483 Discovery [RFC8201], in order to discover and take advantage of 484 path MTUs greater than 1280 octets. However, a minimal IPv6 485 implementation (e.g., in a boot ROM) may simply restrict itself to 486 sending packets no larger than 1280 octets, and omit 487 implementation of Path MTU Discovery. 489 The rules in [RFC8200] and [RFC5722] MUST be followed for packet 490 fragmentation and reassembly. 492 One operational issue with Path MTU Discovery occurs when, contrary 493 to the guidance in [RFC4890], firewalls block ICMP Packet Too Big 494 messages. Path MTU Discovery relies on such messages to determine 495 what size messages can be successfully sent. "Packetization Layer 496 Path MTU Discovery" [RFC4821] avoids having a dependency on Packet 497 Too Big messages. 499 5.7.2. Minimum MTU considerations 501 While an IPv6 link MTU can be set to 1280 bytes, it is recommended 502 that for IPv6 UDP in particular, which includes DNS operation, the 503 sender use a large MTU if they can, in order to avoid gratuitous 504 fragmentation-caused packet drops. 506 5.8. ICMP for the Internet Protocol Version 6 (IPv6) - RFC 4443 508 ICMPv6 [RFC4443] MUST be supported. "Extended ICMP to Support Multi- 509 Part Messages" [RFC4884] MAY be supported. 511 5.9. Default Router Preferences and More-Specific Routes - RFC 4191 513 "Default Router Preferences and More-Specific Routes" [RFC4191] 514 provides support for nodes attached to multiple (different) networks, 515 each providing routers that advertise themselves as default routers 516 via Router Advertisements. In some scenarios, one router may provide 517 connectivity to destinations the other router does not, and choosing 518 the "wrong" default router can result in reachability failures. In 519 order to resolve this scenario IPv6 Nodes MUST implement [RFC4191] 520 and SHOULD implement the Type C host role defined in RFC4191. 522 5.10. First-Hop Router Selection - RFC 8028 524 In multihomed scenarios, where a host has more than one prefix, each 525 allocated by an upstream network that is assumed to implement BCP 38 526 ingress filtering, the host may have multiple routers to choose from. 528 Hosts that may be deployed in such multihomed environments SHOULD 529 follow the guidance given in [RFC8028]. 531 5.11. Multicast Listener Discovery (MLD) for IPv6 - RFC 3810 533 Nodes that need to join multicast groups MUST support MLDv2 534 [RFC3810]. MLD is needed by any node that is expected to receive and 535 process multicast traffic and in particular MLDv2 is required for 536 support for source-specific multicast (SSM) as per [RFC4607]. 538 Previous versions of this document only required MLDv1 ([RFC2710]) to 539 be implemented on all nodes. Since participation of any MLDv1-only 540 nodes on a link require that all other nodeas on the link then 541 operate in version 1 compatibility mode, the requirement to support 542 MLDv2 on all nodes was upgraded to a MUST. Further, SSM is now the 543 preferred multicast distribution method, rather than ASM. 545 Note that Neighbor Discovery (as used on most link types -- see 546 Section 5.4) depends on multicast and requires that nodes join 547 Solicited Node multicast addresses. 549 5.12. Explicit Congestion Notification (ECN) - RFC 3168 551 An ECN-aware router may set a mark in the IP header in order to 552 signal impending congestion, rather than dropping a packet. The 553 receiver of the packet echoes the congestion indication to the 554 sender, which can then reduce its transmission rate as if it detected 555 a dropped packet. 557 Nodes that may be deployed in environments where they would benefit 558 from such early congestion notification SHOULD implement [RFC3168]. 559 In such cases, the updates presented in [RFC8311] may also be 560 relevant. 562 6. Addressing and Address Configuration 564 6.1. IP Version 6 Addressing Architecture - RFC 4291 566 The IPv6 Addressing Architecture [RFC4291] MUST be supported. 568 The current IPv6 Address Architecture is based on a 64-bit boundary 569 for subnet prefixes. The reasoning behind this decision is 570 documented in [RFC7421]. 572 6.2. Host Address Availability Recommendations 574 Hosts may be configured with addresses through a variety of methods, 575 including SLAAC, DHCPv6, or manual configuration. 577 [RFC7934] recommends that networks provide general-purpose end hosts 578 with multiple global IPv6 addresses when they attach, and it 579 describes the benefits of and the options for doing so. Router 580 SHOULD support [RFC7934] for assigning multiple address to a host. 581 Host SHOULD support assigning multiple addresses as described in 582 [RFC7934]. 584 Nodes SHOULD support the capability to be assigned a prefix per host 585 as documented in [RFC8273]. Such an approach can offer improved host 586 isolation and enhanced subscriber management on shared network 587 segments. 589 6.3. IPv6 Stateless Address Autoconfiguration - RFC 4862 591 Hosts MUST support IPv6 Stateless Address Autoconfiguration. It is 592 recommended, as described in [RFC8064], that unless there is a 593 specific requirement for MAC addresses to be embedded in an IID, 594 nodes follow the procedure in [RFC7217] to generate SLAAC-based 595 addresses, rather than using [RFC4862]. Addresses generated through 596 RFC7217 will be the same whenever a given device (re)appears on the 597 same subnet (with a specific IPv6 prefix), but the IID will vary on 598 each subnet visited. 600 Nodes that are routers MUST be able to generate link-local addresses 601 as described in [RFC4862]. 603 From RFC 4862: 605 The autoconfiguration process specified in this document applies 606 only to hosts and not routers. Since host autoconfiguration uses 607 information advertised by routers, routers will need to be 608 configured by some other means. However, it is expected that 609 routers will generate link-local addresses using the mechanism 610 described in this document. In addition, routers are expected to 611 successfully pass the Duplicate Address Detection procedure 612 described in this document on all addresses prior to assigning 613 them to an interface. 615 All nodes MUST implement Duplicate Address Detection. Quoting from 616 Section 5.4 of RFC 4862: 618 Duplicate Address Detection MUST be performed on all unicast 619 addresses prior to assigning them to an interface, regardless of 620 whether they are obtained through stateless autoconfiguration, 621 DHCPv6, or manual configuration, with the following [exceptions 622 noted therein]. 624 "Optimistic Duplicate Address Detection (DAD) for IPv6" [RFC4429] 625 specifies a mechanism to reduce delays associated with generating 626 addresses via Stateless Address Autoconfiguration [RFC4862]. RFC 627 4429 was developed in conjunction with Mobile IPv6 in order to reduce 628 the time needed to acquire and configure addresses as devices quickly 629 move from one network to another, and it is desirable to minimize 630 transition delays. For general purpose devices, RFC 4429 remains 631 optional at this time. 633 [RFC7527] discusses enhanced DAD, and describes an algorithm to 634 automate the detection of looped back IPv6 ND messages used by DAD. 635 Nodes SHOULD implement this behaviour where such detection is 636 beneficial. 638 6.4. Privacy Extensions for Address Configuration in IPv6 - RFC 4941 640 A node using Stateless Address Autoconfiguration [RFC4862] to form a 641 globally unique IPv6 address using its MAC address to generate the 642 IID will see that IID remain the same on any visited network, even 643 though the network prefix part changes. Thus it is possible for 3rd 644 party devices such nodes communicate with to track the activities of 645 the node as it moves around the network. Privacy Extensions for 646 Stateless Address Autoconfiguration [RFC4941] address this concern by 647 allowing nodes to configure an additional temporary address where the 648 IID is effectively randomly generated. Privacy addresses are then 649 used as source addresses for new communications initiated by the 650 node. 652 General issues regarding privacy issues for IPv6 addressing are 653 discussed in [RFC7721]. 655 RFC 4941 SHOULD be supported. In some scenarios, such as dedicated 656 servers in a data center, it provides limited or no benefit, or may 657 complicate network management. Thus devices implementing this 658 specification MUST provide a way for the end user to explicitly 659 enable or disable the use of such temporary addresses. 661 Note that RFC4941 can be used independently of traditional SLAAC, or 662 of RFC7217-based SLAAC. 664 Implementers of RFC 4941 should be aware that certain addresses are 665 reserved and should not be chosen for use as temporary addresses. 666 Consult "Reserved IPv6 Interface Identifiers" [RFC5453] for more 667 details. 669 6.5. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 671 DHCPv6 [RFC3315] can be used to obtain and configure addresses. In 672 general, a network may provide for the configuration of addresses 673 through SLAAC, DHCPv6, or both. There will be a wide range of IPv6 674 deployment models and differences in address assignment requirements, 675 some of which may require DHCPv6 for stateful address assignment. 676 Consequently, all hosts SHOULD implement address configuration via 677 DHCPv6. 679 In the absence of observed Router Advertisement messages, IPv6 nodes 680 MAY initiate DHCP to obtain IPv6 addresses and other configuration 681 information, as described in Section 5.5.2 of [RFC4862]. 683 Where devices are likely to be carried by users and attached to 684 multiple visisted networks, DHCPv6 client anonymity profiles SHOULD 685 be supported as described in [RFC7844] to minimise the disclosure of 686 identifying information. Section 5 of RFC7844 describes operational 687 considerations on the use of such anonymity profiles. 689 6.6. Default Address Selection for IPv6 - RFC 6724 691 IPv6 nodes will invariably have multiple addresses configured 692 simultaneously, and thus will need to choose which addresses to use 693 for which communications. The rules specified in the Default Address 694 Selection for IPv6 [RFC6724] document MUST be implemented. [RFC8028] 695 updates rule 5.5 from [RFC6724]; implementations SHOULD implement 696 this rule. 698 7. DNS 700 DNS is described in [RFC1034], [RFC1035], [RFC3363], and [RFC3596]. 701 Not all nodes will need to resolve names; those that will never need 702 to resolve DNS names do not need to implement resolver functionality. 703 However, the ability to resolve names is a basic infrastructure 704 capability on which applications rely, and most nodes will need to 705 provide support. All nodes SHOULD implement stub-resolver [RFC1034] 706 functionality, as in [RFC1034], Section 5.3.1, with support for: 708 - AAAA type Resource Records [RFC3596]; 710 - reverse addressing in ip6.arpa using PTR records [RFC3596]; 711 - Extension Mechanisms for DNS (EDNS0) [RFC6891] to allow for DNS 712 packet sizes larger than 512 octets. 714 Those nodes are RECOMMENDED to support DNS security extensions 715 [RFC4033] [RFC4034] [RFC4035]. 717 A6 Resource Records, which were only ever defined with Experimental 718 status in [RFC3363], are now classified as Historic, as per 719 [RFC6563]. 721 8. Configuring Non-Address Information 723 8.1. DHCP for Other Configuration Information 725 DHCP [RFC3315] Specifies a mechanism for IPv6 nodes to obtain address 726 configuration information (see Section 6.5) and to obtain additional 727 (non-address) configuration. If a host implementation supports 728 applications or other protocols that require configuration that is 729 only available via DHCP, hosts SHOULD implement DHCP. For 730 specialized devices on which no such configuration need is present, 731 DHCP may not be necessary. 733 An IPv6 node can use the subset of DHCP (described in [RFC3736]) to 734 obtain other configuration information. 736 If an IPv6 node implements DHCP it MUST implement the DNS options 737 [RFC3646] as most deployments will expect this options are available. 739 8.2. Router Advertisements and Default Gateway 741 There is no defined DHCPv6 Gateway option. 743 Nodes using the Dynamic Host Configuration Protocol for IPv6 (DHCPv6) 744 are thus expected to determine their default router information and 745 on-link prefix information from received Router Advertisements. 747 8.3. IPv6 Router Advertisement Options for DNS Configuration - RFC 8106 749 Router Advertisement Options have historically been limited to those 750 that are critical to basic IPv6 functionality. Originally, DNS 751 configuration was not included as an RA option, and DHCP was the 752 recommended way to obtain DNS configuration information. Over time, 753 the thinking surrounding such an option has evolved. It is now 754 generally recognized that few nodes can function adequately without 755 having access to a working DNS resolver, and thus a Standards Track 756 document has been published to provide this capability [RFC8106]. 758 Implementations MUST include support for the DNS RA option [RFC8106]. 760 8.4. DHCP Options versus Router Advertisement Options for Host 761 Configuration 763 In IPv6, there are two main protocol mechanisms for propagating 764 configuration information to hosts: Router Advertisements (RAs) and 765 DHCP. RA options have been restricted to those deemed essential for 766 basic network functioning and for which all nodes are configured with 767 exactly the same information. Examples include the Prefix 768 Information Options, the MTU option, etc. On the other hand, DHCP 769 has generally been preferred for configuration of more general 770 parameters and for parameters that may be client-specific. Generally 771 speaking, however, there has been a desire to define only one 772 mechanism for configuring a given option, rather than defining 773 multiple (different) ways of configuring the same information. 775 One issue with having multiple ways of configuring the same 776 information is that interoperability suffers if a host chooses one 777 mechanism but the network operator chooses a different mechanism. 778 For "closed" environments, where the network operator has significant 779 influence over what devices connect to the network and thus what 780 configuration mechanisms they support, the operator may be able to 781 ensure that a particular mechanism is supported by all connected 782 hosts. In more open environments, however, where arbitrary devices 783 may connect (e.g., a WIFI hotspot), problems can arise. To maximize 784 interoperability in such environments, hosts would need to implement 785 multiple configuration mechanisms to ensure interoperability. 787 9. Service Discovery Protocols 789 [RFC6762] and [RFC6763] describe multicast DNS (mDNS) and DNS-Based 790 Service Discovery (DNS-SD) respectively. These protocols, 791 collectively commonly referred to as the 'Bonjour' protocols after 792 their naming by Apple, provide the means for devices to discover 793 services within a local link and, in the absence of a unicast DNS 794 service, to exchange naming information. 796 Where devices are to be deployed in networks where service dicovery 797 would be beneficial, e.g., for users seeking to discover printers or 798 display devices, mDNS and DNS-SD SHOULD be supported. 800 The IETF dnssd WG is defining solutions for DNS-based service 801 discovery in multi-link networks. 803 10. IPv4 Support and Transition 805 IPv6 nodes MAY support IPv4. 807 10.1. Transition Mechanisms 809 10.1.1. Basic Transition Mechanisms for IPv6 Hosts and Routers - RFC 810 4213 812 If an IPv6 node implements dual stack and tunneling, then [RFC4213] 813 MUST be supported. 815 11. Application Support 817 11.1. Textual Representation of IPv6 Addresses - RFC 5952 819 Software that allows users and operators to input IPv6 addresses in 820 text form SHOULD support "A Recommendation for IPv6 Address Text 821 Representation" [RFC5952]. 823 11.2. Application Programming Interfaces (APIs) 825 There are a number of IPv6-related APIs. This document does not 826 mandate the use of any, because the choice of API does not directly 827 relate to on-the-wire behavior of protocols. Implementers, however, 828 would be advised to consider providing a common API or reviewing 829 existing APIs for the type of functionality they provide to 830 applications. 832 "Basic Socket Interface Extensions for IPv6" [RFC3493] provides IPv6 833 functionality used by typical applications. Implementers should note 834 that RFC3493 has been picked up and further standardized by the 835 Portable Operating System Interface (POSIX) [POSIX]. 837 "Advanced Sockets Application Program Interface (API) for IPv6" 838 [RFC3542] provides access to advanced IPv6 features needed by 839 diagnostic and other more specialized applications. 841 "IPv6 Socket API for Source Address Selection" [RFC5014] provides 842 facilities that allow an application to override the default Source 843 Address Selection rules of [RFC6724]. 845 "Socket Interface Extensions for Multicast Source Filters" [RFC3678] 846 provides support for expressing source filters on multicast group 847 memberships. 849 "Extension to Sockets API for Mobile IPv6" [RFC4584] provides 850 application support for accessing and enabling Mobile IPv6 [RFC6275] 851 features. 853 12. Mobility 855 Mobile IPv6 [RFC6275] and associated specifications [RFC3776] 856 [RFC4877] allow a node to change its point of attachment within the 857 Internet, while maintaining (and using) a permanent address. All 858 communication using the permanent address continues to proceed as 859 expected even as the node moves around. The definition of Mobile IP 860 includes requirements for the following types of nodes: 862 - mobile nodes 864 - correspondent nodes with support for route optimization 866 - home agents 868 - all IPv6 routers 870 At the present time, Mobile IP has seen only limited implementation 871 and no significant deployment, partly because it originally assumed 872 an IPv6-only environment rather than a mixed IPv4/IPv6 Internet. 873 Recently, additional work has been done to support mobility in mixed- 874 mode IPv4 and IPv6 networks [RFC5555]. 876 More usage and deployment experience is needed with mobility before 877 any specific approach can be recommended for broad implementation in 878 all hosts and routers. Consequently, [RFC6275], [RFC5555], and 879 associated standards such as [RFC4877] are considered a MAY at this 880 time. 882 IPv6 for 3GPP [RFC7066] lists a snapshot of required IPv6 883 Functionalities at the time the document was published that would 884 need to be implemented, going above and beyond the recommendations in 885 this document. Additionally a 3GPP IPv6 Host MAY implement [RFC7278] 886 for delivering IPv6 prefixes on the LAN link. 888 13. Security 890 This section describes the specification for security for IPv6 nodes. 892 Achieving security in practice is a complex undertaking. Operational 893 procedures, protocols, key distribution mechanisms, certificate 894 management approaches, etc., are all components that impact the level 895 of security actually achieved in practice. More importantly, 896 deficiencies or a poor fit in any one individual component can 897 significantly reduce the overall effectiveness of a particular 898 security approach. 900 IPsec either can provide end-to-end security between nodes or or can 901 provide channel security (for example, via a site-to-site IPsec VPN), 902 making it possible to provide secure communication for all (or a 903 subset of) communication flows at the IP layer between pairs of 904 internet nodes. IPsec has two standard operating modes, Tunnel-mode 905 and Transport-mode. In Tunnel-mode, IPsec provides network-layer 906 security and protects an entire IP packet by encapsulating the 907 orginal IP packet and then pre-pending a new IP header. In 908 Transport-mode, IPsec provides security for the transport-layer (and 909 above) by encapsulating only the transport-layer (and above) portion 910 of the IP packet (i.e., without adding a 2nd IP header). 912 Although IPsec can be used with manual keying in some cases, such 913 usage has limited applicability and is not recommended. 915 A range of security technologies and approaches proliferate today 916 (e.g., IPsec, Transport Layer Security (TLS), Secure SHell (SSH), SSL 917 VPNS, etc.) No one approach has emerged as an ideal technology for 918 all needs and environments. Moreover, IPsec is not viewed as the 919 ideal security technology in all cases and is unlikely to displace 920 the others. 922 Previously, IPv6 mandated implementation of IPsec and recommended the 923 key management approach of IKE. This document updates that 924 recommendation by making support of the IPsec Architecture [RFC4301] 925 a SHOULD for all IPv6 nodes. Note that the IPsec Architecture 926 requires (e.g., Section 4.5 of RFC 4301) the implementation of both 927 manual and automatic key management. Currently, the default 928 automated key management protocol to implement is IKEv2 [RFC7296]. 930 This document recognizes that there exists a range of device types 931 and environments where approaches to security other than IPsec can be 932 justified. For example, special-purpose devices may support only a 933 very limited number or type of applications, and an application- 934 specific security approach may be sufficient for limited management 935 or configuration capabilities. Alternatively, some devices may run 936 on extremely constrained hardware (e.g., sensors) where the full 937 IPsec Architecture is not justified. 939 Because most common platforms now support IPv6 and have it enabled by 940 default, IPv6 security is an issue for networks that are ostensibly 941 IPv4-only; see [RFC7123] for guidance on this area. 943 13.1. Requirements 945 "Security Architecture for the Internet Protocol" [RFC4301] SHOULD be 946 supported by all IPv6 nodes. Note that the IPsec Architecture 947 requires (e.g., Section 4.5 of [RFC4301]) the implementation of both 948 manual and automatic key management. Currently, the default 949 automated key management protocol to implement is IKEv2. As required 950 in [RFC4301], IPv6 nodes implementing the IPsec Architecture MUST 951 implement ESP [RFC4303] and MAY implement AH [RFC4302]. 953 13.2. Transforms and Algorithms 955 The current set of mandatory-to-implement algorithms for the IPsec 956 Architecture are defined in "Cryptographic Algorithm Implementation 957 Requirements For ESP and AH" [RFC8221]. IPv6 nodes implementing the 958 IPsec Architecture MUST conform to the requirements in [RFC8221]. 959 Preferred cryptographic algorithms often change more frequently than 960 security protocols. Therefore, implementations MUST allow for 961 migration to new algorithms, as RFC 8221 is replaced or updated in 962 the future. 964 The current set of mandatory-to-implement algorithms for IKEv2 are 965 defined in "Cryptographic Algorithms for Use in the Internet Key 966 Exchange Version 2 (IKEv2)" [RFC8247]. IPv6 nodes implementing IKEv2 967 MUST conform to the requirements in [RFC8247] and/or any future 968 updates or replacements to [RFC8247]. 970 14. Router-Specific Functionality 972 This section defines general host considerations for IPv6 nodes that 973 act as routers. Currently, this section does not discuss detailed 974 routing-specific requirements. For the case of typical home routers, 975 [RFC7084] defines basic requirements for customer edge routers. 977 Further recommendations on router-specific functionality can be found 978 in [I-D.ietf-v6ops-ipv6rtr-reqs]. 980 14.1. IPv6 Router Alert Option - RFC 2711 982 The IPv6 Router Alert Option [RFC2711] is an optional IPv6 Hop-by-Hop 983 Header that is used in conjunction with some protocols (e.g., RSVP 984 [RFC2205] or Multicast Listener Discovery (MLDv2) [RFC3810]). The 985 Router Alert option will need to be implemented whenever such 986 protocols that mandate its use are implemented. See Section 5.11. 988 14.2. Neighbor Discovery for IPv6 - RFC 4861 990 Sending Router Advertisements and processing Router Solicitations 991 MUST be supported. 993 Section 7 of [RFC6275] includes some mobility-specific extensions to 994 Neighbor Discovery. Routers SHOULD implement Sections 7.3 and 7.5, 995 even if they do not implement Home Agent functionality. 997 14.3. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315 999 A single DHCP server ([RFC3315] or [RFC4862]) can provide 1000 configuration information to devices directly attached to a shared 1001 link, as well as to devices located elsewhere within a site. 1002 Communication between a client and a DHCP server located on different 1003 links requires the use of DHCP relay agents on routers. 1005 In simple deployments, consisting of a single router and either a 1006 single LAN or multiple LANs attached to the single router, together 1007 with a WAN connection, a DHCP server embedded within the router is 1008 one common deployment scenario (e.g., [RFC7084]). There is no need 1009 for relay agents in such scenarios. 1011 In more complex deployment scenarios, such as within enterprise or 1012 service provider networks, the use of DHCP requires some level of 1013 configuration, in order to configure relay agents, DHCP servers, etc. 1014 In such environments, the DHCP server might even be run on a 1015 traditional server, rather than as part of a router. 1017 Because of the wide range of deployment scenarios, support for DHCP 1018 server functionality on routers is optional. However, routers 1019 targeted for deployment within more complex scenarios (as described 1020 above) SHOULD support relay agent functionality. Note that "Basic 1021 Requirements for IPv6 Customer Edge Routers" [RFC7084] requires 1022 implementation of a DHCPv6 server function in IPv6 Customer Edge (CE) 1023 routers. 1025 14.4. IPv6 Prefix Length Recommendation for Forwarding - BCP 198 1027 Forwarding nodes MUST conform to BCP 198 [RFC7608] and thus IPv6 1028 implementations of nodes that may forward packets MUST conform to the 1029 rules specified in Section 5.1 of [RFC4632]. 1031 15. Constrained Devices 1033 The target for this document is general IPv6 nodes. In the case of 1034 constrained nodes, with limited CPU, memory, bandwidth or power, 1035 support for certain IPv6 functionality may need to be considered due 1036 to those limitations. The requirements of this document are 1037 RECOMMENDED for all nodes, including constrained nodes, but 1038 compromises may need to be made in certain cases. Where such 1039 compromises are made, the interoperability of devices should be 1040 strongly considered, paticularly where this may impact other nodes on 1041 the same link, e.g., only supporting MLDv1 will affect other nodes. 1043 The IETF 6LowPAN (IPv6 over Low Power LWPAN) WG defined six RFCs, 1044 including a general overview and problem statement ([RFC4919], the 1045 means by which IPv6 packets are transmitted over IEEE 802.15.4 1046 networks [RFC4944] and ND optimisations for that medium [RFC6775]. 1048 If an IPv6 node is concerned about the impact of IPv6 message power 1049 consumption, it SHOULD want to implement the recommendations in 1050 [RFC7772]. 1052 16. Network Management 1054 Network management MAY be supported by IPv6 nodes. However, for IPv6 1055 nodes that are embedded devices, network management may be the only 1056 possible way of controlling these nodes. 1058 A node supporting network management SHOULD support NETCONF [RFC6241] 1059 and SNMP configuration [RFC3411]. 1061 16.1. Management Information Base (MIB) Modules 1063 IPv6 MIBs have been updated since the last release of the document; 1064 [RFC8096] obseletes several MIBs, which nodes need no longer support. 1066 The following two MIB modules SHOULD be supported by nodes that 1067 support a Simple Network Management Protocol (SNMP) agent. 1069 16.1.1. IP Forwarding Table MIB 1071 The IP Forwarding Table MIB [RFC4292] SHOULD be supported by nodes 1072 that support an SNMP agent. 1074 16.1.2. Management Information Base for the Internet Protocol (IP) 1076 The IP MIB [RFC4293] SHOULD be supported by nodes that support an 1077 SNMP agent. 1079 16.2. YANG Data Models 1081 The following YANG data models SHOULD be supported by nodes that 1082 support a NETCONF agent. 1084 16.2.1. IP Management YANG Model 1086 The IP Management YANG Model [RFC7277] SHOULD be supported by nodes 1087 that support NETCONF. 1089 16.2.2. System Management YANG Model 1091 The System Management YANG Model [RFC7317] SHOULD be supported by 1092 nodes that support NETCONF. 1094 16.2.3. System Management YANG Model 1096 The Interface Management YANG Model [RFC7223] SHOULD be supported by 1097 nodes that support NETCONF. 1099 17. Security Considerations 1101 This document does not directly affect the security of the Internet, 1102 beyond the security considerations associated with the individual 1103 protocols. 1105 Security is also discussed in Section 13 above. 1107 18. IANA Considerations 1109 This document does not require any IANA actions. 1111 19. Authors and Acknowledgments 1113 19.1. Authors and Acknowledgments (Current Document) 1115 For this version of the IPv6 Node Requirements document, the authors 1116 would like to thank Brian Carpenter, Dave Thaler, Tom Herbert, Erik 1117 Kline, Mohamed Boucadair, and Michayla Newcombe for their 1118 contributions. 1120 19.2. Authors and Acknowledgments from RFC 6434 1122 Ed Jankiewicz and Thomas Narten were named authors of the previous 1123 iteration of this document, RFC6434. 1125 For this version of the document, the authors thanked Hitoshi Asaeda, 1126 Brian Carpenter, Tim Chown, Ralph Droms, Sheila Frankel, Sam Hartman, 1127 Bob Hinden, Paul Hoffman, Pekka Savola, Yaron Sheffer, and Dave 1128 Thaler. 1130 19.3. Authors and Acknowledgments from RFC 4294 1132 The original version of this document (RFC 4294) was written by the 1133 IPv6 Node Requirements design team: 1135 Jari Arkko 1136 jari.arkko@ericsson.com 1138 Marc Blanchet 1139 marc.blanchet@viagenie.qc.ca 1141 Samita Chakrabarti 1142 samita.chakrabarti@eng.sun.com 1144 Alain Durand 1145 alain.durand@sun.com 1147 Gerard Gastaud 1148 gerard.gastaud@alcatel.fr 1150 Jun-ichiro Itojun Hagino 1151 itojun@iijlab.net 1153 Atsushi Inoue 1154 inoue@isl.rdc.toshiba.co.jp 1156 Masahiro Ishiyama 1157 masahiro@isl.rdc.toshiba.co.jp 1159 John Loughney 1160 john.loughney@nokia.com 1162 Rajiv Raghunarayan 1163 raraghun@cisco.com 1164 Shoichi Sakane 1165 shouichi.sakane@jp.yokogawa.com 1167 Dave Thaler 1168 dthaler@windows.microsoft.com 1170 Juha Wiljakka 1171 juha.wiljakka@Nokia.com 1173 The authors would like to thank Ran Atkinson, Jim Bound, Brian 1174 Carpenter, Ralph Droms, Christian Huitema, Adam Machalek, Thomas 1175 Narten, Juha Ollila, and Pekka Savola for their comments. Thanks to 1176 Mark Andrews for comments and corrections on DNS text. Thanks to 1177 Alfred Hoenes for tracking the updates to various RFCs. 1179 20. Appendix: Changes from RFC 6434 1181 There have been many editorial clarifications as well as significant 1182 additions and updates. While this section highlights some of the 1183 changes, readers should not rely on this section for a comprehensive 1184 list of all changes. 1186 1. Restructured sections 1188 2. Added 6LoWPAN to link layers as it has some deployment. 1190 3. Removed DOD IPv6 Profile as it hasn't been updated. 1192 4. Updated to MLDv2 support to a MUST since nodes are restricted if 1193 MLDv1 is used. 1195 5. Require DNS RA Options so SLAAC-only devices can get DNS, 1196 RFC8106 is a MUST. 1198 6. Require RFC3646 DNS Options for DHCPv6 implementations. 1200 7. Added section on constrained devices. 1202 8. Added text on RFC7934, address availability to hosts (SHOULD). 1204 9. Added text on RFC7844, anonymity profiles for DHCPv6 clients. 1206 10. mDNS and DNS-SD added as updated service discovery. 1208 11. Added RFC8028 as a SHOULD as a method for solving multi-prefix 1209 network 1211 12. Added ECN RFC3168 as a SHOULD, since recent reports have shown 1212 this as useful, and added a note on RFC8311, which is related. 1214 13. Added reference to RFC7123 for Security over IPv4-only networks 1216 14. Removed Jumbograms RFC2675 as they aren't deployed. 1218 15. Updated Obseleted RFCs to the new version of the RFC including 1219 2460, 1981, 7321, 4307 1221 16. Added RFC7772 for power comsumptions considerations 1223 17. Added why /64 boundries for more detail - RFC 7421 1225 18. Added a Unique IPv6 Prefix per Host to support currently 1226 deployed IPv6 networks 1228 19. Clarified RFC7066 was snapshot for 3GPP 1230 20. Updated 4191 as a MUST, SHOULD for Type C Host as it helps solve 1231 multi-prefix problem 1233 21. Removed IPv6 over ATM since there aren't many deployments 1235 22. Added a note in Section 6.6 for RFC6724 Section 5.5/ 1237 23. Added MUST for BCP 198 for forwarding IPv6 packets 1239 24. Added reference to draft-ietf-v6ops-ipv6rtr-reqs as it has more 1240 recommendations for a Router 1242 25. Added reference to RFC8064 for stable address creation. 1244 26. Added text on protection from excessive EH options 1246 27. Added text on dangers of 1280 MTU UDP, esp. wrt DNS traffic 1248 28. Added text to clarify RFC8200 behaviour for unrecognized EHs or 1249 unrecognized ULPs 1251 21. Appendix: Changes from RFC 4294 1253 There have been many editorial clarifications as well as significant 1254 additions and updates. While this section highlights some of the 1255 changes, readers should not rely on this section for a comprehensive 1256 list of all changes. 1258 1. Updated the Introduction to indicate that this document is an 1259 applicability statement and is aimed at general nodes. 1261 2. Significantly updated the section on Mobility protocols, adding 1262 references and downgrading previous SHOULDs to MAYs. 1264 3. Changed Sub-IP Layer section to just list relevant RFCs, and 1265 added some more RFCs. 1267 4. Added section on SEND (it is a MAY). 1269 5. Revised section on Privacy Extensions [RFC4941] to add more 1270 nuance to recommendation. 1272 6. Completely revised IPsec/IKEv2 section, downgrading overall 1273 recommendation to a SHOULD. 1275 7. Upgraded recommendation of DHCPv6 to SHOULD. 1277 8. Added background section on DHCP versus RA options, added SHOULD 1278 recommendation for DNS configuration via RAs (RFC6106), and 1279 cleaned up DHCP recommendations. 1281 9. Added recommendation that routers implement Sections 7.3 and 7.5 1282 of [RFC6275]. 1284 10. Added pointer to subnet clarification document [RFC5942]. 1286 11. Added text that "IPv6 Host-to-Router Load Sharing" [RFC4311] 1287 SHOULD be implemented. 1289 12. Added reference to [RFC5722] (Overlapping Fragments), and made 1290 it a MUST to implement. 1292 13. Made "A Recommendation for IPv6 Address Text Representation" 1293 [RFC5952] a SHOULD. 1295 14. Removed mention of "DNAME" from the discussion about [RFC3363]. 1297 15. Numerous updates to reflect newer versions of IPv6 documents, 1298 including [RFC4443], [RFC4291], [RFC3596], and [RFC4213]. 1300 16. Removed discussion of "Managed" and "Other" flags in RAs. There 1301 is no consensus at present on how to process these flags, and 1302 discussion of their semantics was removed in the most recent 1303 update of Stateless Address Autoconfiguration [RFC4862]. 1305 17. Added many more references to optional IPv6 documents. 1307 18. Made "A Recommendation for IPv6 Address Text Representation" 1308 [RFC5952] a SHOULD. 1310 19. Added reference to [RFC5722] (Overlapping Fragments), and made 1311 it a MUST to implement. 1313 20. Updated MLD section to include reference to Lightweight MLD 1314 [RFC5790]. 1316 21. Added SHOULD recommendation for "Default Router Preferences and 1317 More-Specific Routes" [RFC4191]. 1319 22. Made "IPv6 Flow Label Specification" [RFC6437] a SHOULD. 1321 22. References 1323 22.1. Normative References 1325 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1326 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1327 . 1329 [RFC1035] Mockapetris, P., "Domain names - implementation and 1330 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1331 November 1987, . 1333 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1334 Requirement Levels", BCP 14, RFC 2119, 1335 DOI 10.17487/RFC2119, March 1997, 1336 . 1338 [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast 1339 Listener Discovery (MLD) for IPv6", RFC 2710, 1340 DOI 10.17487/RFC2710, October 1999, 1341 . 1343 [RFC2711] Partridge, C. and A. Jackson, "IPv6 Router Alert Option", 1344 RFC 2711, DOI 10.17487/RFC2711, October 1999, 1345 . 1347 [RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition 1348 of Explicit Congestion Notification (ECN) to IP", 1349 RFC 3168, DOI 10.17487/RFC3168, September 2001, 1350 . 1352 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 1353 C., and M. Carney, "Dynamic Host Configuration Protocol 1354 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 1355 2003, . 1357 [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An 1358 Architecture for Describing Simple Network Management 1359 Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, 1360 DOI 10.17487/RFC3411, December 2002, 1361 . 1363 [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, 1364 "DNS Extensions to Support IP Version 6", STD 88, 1365 RFC 3596, DOI 10.17487/RFC3596, October 2003, 1366 . 1368 [RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol 1369 (DHCP) Service for IPv6", RFC 3736, DOI 10.17487/RFC3736, 1370 April 2004, . 1372 [RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener 1373 Discovery Version 2 (MLDv2) for IPv6", RFC 3810, 1374 DOI 10.17487/RFC3810, June 2004, 1375 . 1377 [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1378 Rose, "DNS Security Introduction and Requirements", 1379 RFC 4033, DOI 10.17487/RFC4033, March 2005, 1380 . 1382 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1383 Rose, "Resource Records for the DNS Security Extensions", 1384 RFC 4034, DOI 10.17487/RFC4034, March 2005, 1385 . 1387 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1388 Rose, "Protocol Modifications for the DNS Security 1389 Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005, 1390 . 1392 [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms 1393 for IPv6 Hosts and Routers", RFC 4213, 1394 DOI 10.17487/RFC4213, October 2005, 1395 . 1397 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 1398 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 1399 2006, . 1401 [RFC4292] Haberman, B., "IP Forwarding Table MIB", RFC 4292, 1402 DOI 10.17487/RFC4292, April 2006, 1403 . 1405 [RFC4293] Routhier, S., Ed., "Management Information Base for the 1406 Internet Protocol (IP)", RFC 4293, DOI 10.17487/RFC4293, 1407 April 2006, . 1409 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 1410 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 1411 December 2005, . 1413 [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", 1414 RFC 4303, DOI 10.17487/RFC4303, December 2005, 1415 . 1417 [RFC4311] Hinden, R. and D. Thaler, "IPv6 Host-to-Router Load 1418 Sharing", RFC 4311, DOI 10.17487/RFC4311, November 2005, 1419 . 1421 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1422 Control Message Protocol (ICMPv6) for the Internet 1423 Protocol Version 6 (IPv6) Specification", STD 89, 1424 RFC 4443, DOI 10.17487/RFC4443, March 2006, 1425 . 1427 [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for 1428 IP", RFC 4607, DOI 10.17487/RFC4607, August 2006, 1429 . 1431 [RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing 1432 (CIDR): The Internet Address Assignment and Aggregation 1433 Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August 1434 2006, . 1436 [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, 1437 "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, 1438 DOI 10.17487/RFC4861, September 2007, 1439 . 1441 [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless 1442 Address Autoconfiguration", RFC 4862, 1443 DOI 10.17487/RFC4862, September 2007, 1444 . 1446 [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy 1447 Extensions for Stateless Address Autoconfiguration in 1448 IPv6", RFC 4941, DOI 10.17487/RFC4941, September 2007, 1449 . 1451 [RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation 1452 of Type 0 Routing Headers in IPv6", RFC 5095, 1453 DOI 10.17487/RFC5095, December 2007, 1454 . 1456 [RFC5453] Krishnan, S., "Reserved IPv6 Interface Identifiers", 1457 RFC 5453, DOI 10.17487/RFC5453, February 2009, 1458 . 1460 [RFC5722] Krishnan, S., "Handling of Overlapping IPv6 Fragments", 1461 RFC 5722, DOI 10.17487/RFC5722, December 2009, 1462 . 1464 [RFC5790] Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet 1465 Group Management Protocol Version 3 (IGMPv3) and Multicast 1466 Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790, 1467 DOI 10.17487/RFC5790, February 2010, 1468 . 1470 [RFC5942] Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet 1471 Model: The Relationship between Links and Subnet 1472 Prefixes", RFC 5942, DOI 10.17487/RFC5942, July 2010, 1473 . 1475 [RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 1476 Address Text Representation", RFC 5952, 1477 DOI 10.17487/RFC5952, August 2010, 1478 . 1480 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 1481 and A. Bierman, Ed., "Network Configuration Protocol 1482 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 1483 . 1485 [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, 1486 "IPv6 Flow Label Specification", RFC 6437, 1487 DOI 10.17487/RFC6437, November 2011, 1488 . 1490 [RFC6564] Krishnan, S., Woodyatt, J., Kline, E., Hoagland, J., and 1491 M. Bhatia, "A Uniform Format for IPv6 Extension Headers", 1492 RFC 6564, DOI 10.17487/RFC6564, April 2012, 1493 . 1495 [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown, 1496 "Default Address Selection for Internet Protocol Version 6 1497 (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012, 1498 . 1500 [RFC6762] Cheshire, S. and M. Krochmal, "Multicast DNS", RFC 6762, 1501 DOI 10.17487/RFC6762, February 2013, 1502 . 1504 [RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service 1505 Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013, 1506 . 1508 [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. 1509 Bormann, "Neighbor Discovery Optimization for IPv6 over 1510 Low-Power Wireless Personal Area Networks (6LoWPANs)", 1511 RFC 6775, DOI 10.17487/RFC6775, November 2012, 1512 . 1514 [RFC6891] Damas, J., Graff, M., and P. Vixie, "Extension Mechanisms 1515 for DNS (EDNS(0))", STD 75, RFC 6891, 1516 DOI 10.17487/RFC6891, April 2013, 1517 . 1519 [RFC6946] Gont, F., "Processing of IPv6 "Atomic" Fragments", 1520 RFC 6946, DOI 10.17487/RFC6946, May 2013, 1521 . 1523 [RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing 1524 of IPv6 Extension Headers", RFC 7045, 1525 DOI 10.17487/RFC7045, December 2013, 1526 . 1528 [RFC7048] Nordmark, E. and I. Gashinsky, "Neighbor Unreachability 1529 Detection Is Too Impatient", RFC 7048, 1530 DOI 10.17487/RFC7048, January 2014, 1531 . 1533 [RFC7112] Gont, F., Manral, V., and R. Bonica, "Implications of 1534 Oversized IPv6 Header Chains", RFC 7112, 1535 DOI 10.17487/RFC7112, January 2014, 1536 . 1538 [RFC7217] Gont, F., "A Method for Generating Semantically Opaque 1539 Interface Identifiers with IPv6 Stateless Address 1540 Autoconfiguration (SLAAC)", RFC 7217, 1541 DOI 10.17487/RFC7217, April 2014, 1542 . 1544 [RFC7223] Bjorklund, M., "A YANG Data Model for Interface 1545 Management", RFC 7223, DOI 10.17487/RFC7223, May 2014, 1546 . 1548 [RFC7277] Bjorklund, M., "A YANG Data Model for IP Management", 1549 RFC 7277, DOI 10.17487/RFC7277, June 2014, 1550 . 1552 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 1553 Kivinen, "Internet Key Exchange Protocol Version 2 1554 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 1555 2014, . 1557 [RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for 1558 System Management", RFC 7317, DOI 10.17487/RFC7317, August 1559 2014, . 1561 [RFC7527] Asati, R., Singh, H., Beebee, W., Pignataro, C., Dart, E., 1562 and W. George, "Enhanced Duplicate Address Detection", 1563 RFC 7527, DOI 10.17487/RFC7527, April 2015, 1564 . 1566 [RFC7559] Krishnan, S., Anipko, D., and D. Thaler, "Packet-Loss 1567 Resiliency for Router Solicitations", RFC 7559, 1568 DOI 10.17487/RFC7559, May 2015, 1569 . 1571 [RFC7608] Boucadair, M., Petrescu, A., and F. Baker, "IPv6 Prefix 1572 Length Recommendation for Forwarding", BCP 198, RFC 7608, 1573 DOI 10.17487/RFC7608, July 2015, 1574 . 1576 [RFC7739] Gont, F., "Security Implications of Predictable Fragment 1577 Identification Values", RFC 7739, DOI 10.17487/RFC7739, 1578 February 2016, . 1580 [RFC8021] Gont, F., Liu, W., and T. Anderson, "Generation of IPv6 1581 Atomic Fragments Considered Harmful", RFC 8021, 1582 DOI 10.17487/RFC8021, January 2017, 1583 . 1585 [RFC8028] Baker, F. and B. Carpenter, "First-Hop Router Selection by 1586 Hosts in a Multi-Prefix Network", RFC 8028, 1587 DOI 10.17487/RFC8028, November 2016, 1588 . 1590 [RFC8064] Gont, F., Cooper, A., Thaler, D., and W. Liu, 1591 "Recommendation on Stable IPv6 Interface Identifiers", 1592 RFC 8064, DOI 10.17487/RFC8064, February 2017, 1593 . 1595 [RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, 1596 "IPv6 Router Advertisement Options for DNS Configuration", 1597 RFC 8106, DOI 10.17487/RFC8106, March 2017, 1598 . 1600 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1601 (IPv6) Specification", STD 86, RFC 8200, 1602 DOI 10.17487/RFC8200, July 2017, 1603 . 1605 [RFC8201] McCann, J., Deering, S., Mogul, J., and R. Hinden, Ed., 1606 "Path MTU Discovery for IP version 6", STD 87, RFC 8201, 1607 DOI 10.17487/RFC8201, July 2017, 1608 . 1610 [RFC8221] Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T. 1611 Kivinen, "Cryptographic Algorithm Implementation 1612 Requirements and Usage Guidance for Encapsulating Security 1613 Payload (ESP) and Authentication Header (AH)", RFC 8221, 1614 DOI 10.17487/RFC8221, October 2017, 1615 . 1617 [RFC8247] Nir, Y., Kivinen, T., Wouters, P., and D. Migault, 1618 "Algorithm Implementation Requirements and Usage Guidance 1619 for the Internet Key Exchange Protocol Version 2 (IKEv2)", 1620 RFC 8247, DOI 10.17487/RFC8247, September 2017, 1621 . 1623 [RFC8311] Black, D., "Relaxing Restrictions on Explicit Congestion 1624 Notification (ECN) Experimentation", RFC 8311, 1625 DOI 10.17487/RFC8311, January 2018, 1626 . 1628 22.2. Informative References 1630 [I-D.ietf-v6ops-ipv6rtr-reqs] 1631 Kahn, Z., Brzozowski, J., and R. White, "Requirements for 1632 IPv6 Routers", draft-ietf-v6ops-ipv6rtr-reqs-01 (work in 1633 progress), January 2018. 1635 [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, 1636 RFC 793, DOI 10.17487/RFC0793, September 1981, 1637 . 1639 [RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S. 1640 Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 1641 Functional Specification", RFC 2205, DOI 10.17487/RFC2205, 1642 September 1997, . 1644 [RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet 1645 Networks", RFC 2464, DOI 10.17487/RFC2464, December 1998, 1646 . 1648 [RFC2491] Armitage, G., Schulter, P., Jork, M., and G. Harter, "IPv6 1649 over Non-Broadcast Multiple Access (NBMA) networks", 1650 RFC 2491, DOI 10.17487/RFC2491, January 1999, 1651 . 1653 [RFC2590] Conta, A., Malis, A., and M. Mueller, "Transmission of 1654 IPv6 Packets over Frame Relay Networks Specification", 1655 RFC 2590, DOI 10.17487/RFC2590, May 1999, 1656 . 1658 [RFC3146] Fujisawa, K. and A. Onoe, "Transmission of IPv6 Packets 1659 over IEEE 1394 Networks", RFC 3146, DOI 10.17487/RFC3146, 1660 October 2001, . 1662 [RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. 1663 Hain, "Representing Internet Protocol version 6 (IPv6) 1664 Addresses in the Domain Name System (DNS)", RFC 3363, 1665 DOI 10.17487/RFC3363, August 2002, 1666 . 1668 [RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W. 1669 Stevens, "Basic Socket Interface Extensions for IPv6", 1670 RFC 3493, DOI 10.17487/RFC3493, February 2003, 1671 . 1673 [RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei, 1674 "Advanced Sockets Application Program Interface (API) for 1675 IPv6", RFC 3542, DOI 10.17487/RFC3542, May 2003, 1676 . 1678 [RFC3646] Droms, R., Ed., "DNS Configuration options for Dynamic 1679 Host Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, 1680 DOI 10.17487/RFC3646, December 2003, 1681 . 1683 [RFC3678] Thaler, D., Fenner, B., and B. Quinn, "Socket Interface 1684 Extensions for Multicast Source Filters", RFC 3678, 1685 DOI 10.17487/RFC3678, January 2004, 1686 . 1688 [RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility 1689 Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July 1690 2011, . 1692 [RFC3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to 1693 Protect Mobile IPv6 Signaling Between Mobile Nodes and 1694 Home Agents", RFC 3776, DOI 10.17487/RFC3776, June 2004, 1695 . 1697 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1698 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1699 DOI 10.17487/RFC3971, March 2005, 1700 . 1702 [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", 1703 RFC 3972, DOI 10.17487/RFC3972, March 2005, 1704 . 1706 [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and 1707 More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191, 1708 November 2005, . 1710 [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, 1711 DOI 10.17487/RFC4302, December 2005, 1712 . 1714 [RFC4338] DeSanti, C., Carlson, C., and R. Nixon, "Transmission of 1715 IPv6, IPv4, and Address Resolution Protocol (ARP) Packets 1716 over Fibre Channel", RFC 4338, DOI 10.17487/RFC4338, 1717 January 2006, . 1719 [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through 1720 Network Address Translations (NATs)", RFC 4380, 1721 DOI 10.17487/RFC4380, February 2006, 1722 . 1724 [RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD) 1725 for IPv6", RFC 4429, DOI 10.17487/RFC4429, April 2006, 1726 . 1728 [RFC4584] Chakrabarti, S. and E. Nordmark, "Extension to Sockets API 1729 for Mobile IPv6", RFC 4584, DOI 10.17487/RFC4584, July 1730 2006, . 1732 [RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU 1733 Discovery", RFC 4821, DOI 10.17487/RFC4821, March 2007, 1734 . 1736 [RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with 1737 IKEv2 and the Revised IPsec Architecture", RFC 4877, 1738 DOI 10.17487/RFC4877, April 2007, 1739 . 1741 [RFC4884] Bonica, R., Gan, D., Tappan, D., and C. Pignataro, 1742 "Extended ICMP to Support Multi-Part Messages", RFC 4884, 1743 DOI 10.17487/RFC4884, April 2007, 1744 . 1746 [RFC4890] Davies, E. and J. Mohacsi, "Recommendations for Filtering 1747 ICMPv6 Messages in Firewalls", RFC 4890, 1748 DOI 10.17487/RFC4890, May 2007, 1749 . 1751 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 1752 over Low-Power Wireless Personal Area Networks (6LoWPANs): 1753 Overview, Assumptions, Problem Statement, and Goals", 1754 RFC 4919, DOI 10.17487/RFC4919, August 2007, 1755 . 1757 [RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler, 1758 "Transmission of IPv6 Packets over IEEE 802.15.4 1759 Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007, 1760 . 1762 [RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6 1763 Socket API for Source Address Selection", RFC 5014, 1764 DOI 10.17487/RFC5014, September 2007, 1765 . 1767 [RFC5072] Varada, S., Ed., Haskins, D., and E. Allen, "IP Version 6 1768 over PPP", RFC 5072, DOI 10.17487/RFC5072, September 2007, 1769 . 1771 [RFC5121] Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S. 1772 Madanapalli, "Transmission of IPv6 via the IPv6 1773 Convergence Sublayer over IEEE 802.16 Networks", RFC 5121, 1774 DOI 10.17487/RFC5121, February 2008, 1775 . 1777 [RFC5555] Soliman, H., Ed., "Mobile IPv6 Support for Dual Stack 1778 Hosts and Routers", RFC 5555, DOI 10.17487/RFC5555, June 1779 2009, . 1781 [RFC6563] Jiang, S., Conrad, D., and B. Carpenter, "Moving A6 to 1782 Historic Status", RFC 6563, DOI 10.17487/RFC6563, March 1783 2012, . 1785 [RFC7066] Korhonen, J., Ed., Arkko, J., Ed., Savolainen, T., and S. 1786 Krishnan, "IPv6 for Third Generation Partnership Project 1787 (3GPP) Cellular Hosts", RFC 7066, DOI 10.17487/RFC7066, 1788 November 2013, . 1790 [RFC7084] Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic 1791 Requirements for IPv6 Customer Edge Routers", RFC 7084, 1792 DOI 10.17487/RFC7084, November 2013, 1793 . 1795 [RFC7123] Gont, F. and W. Liu, "Security Implications of IPv6 on 1796 IPv4 Networks", RFC 7123, DOI 10.17487/RFC7123, February 1797 2014, . 1799 [RFC7278] Byrne, C., Drown, D., and A. Vizdal, "Extending an IPv6 1800 /64 Prefix from a Third Generation Partnership Project 1801 (3GPP) Mobile Interface to a LAN Link", RFC 7278, 1802 DOI 10.17487/RFC7278, June 2014, 1803 . 1805 [RFC7421] Carpenter, B., Ed., Chown, T., Gont, F., Jiang, S., 1806 Petrescu, A., and A. Yourtchenko, "Analysis of the 64-bit 1807 Boundary in IPv6 Addressing", RFC 7421, 1808 DOI 10.17487/RFC7421, January 2015, 1809 . 1811 [RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy 1812 Considerations for IPv6 Address Generation Mechanisms", 1813 RFC 7721, DOI 10.17487/RFC7721, March 2016, 1814 . 1816 [RFC7772] Yourtchenko, A. and L. Colitti, "Reducing Energy 1817 Consumption of Router Advertisements", BCP 202, RFC 7772, 1818 DOI 10.17487/RFC7772, February 2016, 1819 . 1821 [RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity 1822 Profiles for DHCP Clients", RFC 7844, 1823 DOI 10.17487/RFC7844, May 2016, 1824 . 1826 [RFC7934] Colitti, L., Cerf, V., Cheshire, S., and D. Schinazi, 1827 "Host Address Availability Recommendations", BCP 204, 1828 RFC 7934, DOI 10.17487/RFC7934, July 2016, 1829 . 1831 [RFC8096] Fenner, B., "The IPv6-Specific MIB Modules Are Obsolete", 1832 RFC 8096, DOI 10.17487/RFC8096, April 2017, 1833 . 1835 [RFC8273] Brzozowski, J. and G. Van de Velde, "Unique IPv6 Prefix 1836 per Host", RFC 8273, DOI 10.17487/RFC8273, December 2017, 1837 . 1839 [POSIX] IEEE, "IEEE Std. 1003.1-2008 Standard for Information 1840 Technology -- Portable Operating System Interface (POSIX), 1841 ISO/IEC 9945:2009", . 1843 [USGv6] National Institute of Standards and Technology, "A Profile 1844 for IPv6 in the U.S. Government - Version 1.0", July 2008, 1845 . 1847 Authors' Addresses 1849 Tim Chown 1850 Jisc 1851 Lumen House, Library Avenue 1852 Harwell Oxford, Didcot OX11 0SG 1853 United Kingdom 1855 Email: tim.chown@jisc.ac.uk 1857 John Loughney 1858 Intel 1859 Santa Clara, CA 1860 USA 1862 Email: john.loughney@gmail.com 1864 Timothy Winters 1865 University of New Hampshire, Interoperability Lab (UNH-IOL) 1866 Durham, NH 1867 United States 1869 Email: twinters@iol.unh.edu