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(See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (March 3, 2006) is 6628 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: '13' is defined on line 1169, but no explicit reference was found in the text ** Obsolete normative reference: RFC 3775 (ref. '2') (Obsoleted by RFC 6275) == Outdated reference: A later version (-05) exists of draft-ietf-mip6-bootstrap-ps-04 ** Downref: Normative reference to an Informational draft: draft-ietf-mip6-bootstrap-ps (ref. '4') == Outdated reference: A later version (-08) exists of draft-ietf-mip6-ikev2-ipsec-04 ** Obsolete normative reference: RFC 4306 (ref. '7') (Obsoleted by RFC 5996) == Outdated reference: A later version (-05) exists of draft-ietf-ipv6-privacy-addrs-v2-04 == Outdated reference: A later version (-03) exists of draft-ietf-mip6-aaa-ha-goals-01 == Outdated reference: A later version (-06) exists of draft-ietf-mip6-bootstrapping-integrated-dhc-00 -- Obsolete informational reference (is this intentional?): RFC 2845 (ref. '17') (Obsoleted by RFC 8945) == Outdated reference: A later version (-03) exists of draft-ietf-mip6-ro-sec-02 == Outdated reference: A later version (-11) exists of draft-ietf-ipv6-2461bis-05 Summary: 9 errors (**), 0 flaws (~~), 18 warnings (==), 7 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MIP6 WG G. Giaretta, Editor 3 Internet Draft Telecom Italia 4 Expires: September 3, 2006 J. Kempf 5 DoCoMo Labs USA 6 V. Devarapalli 7 Nokia 8 March 3, 2006 10 Mobile IPv6 bootstrapping in split scenario 11 draft-ietf-mip6-bootstrapping-split-02.txt 13 Status of this Memo 15 By submitting this Internet-Draft, each author represents that 16 any applicable patent or other IPR claims of which he or she is 17 aware have been or will be disclosed, and any of which he or she 18 becomes aware will be disclosed, in accordance with Section 6 of 19 BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF), its areas, and its working groups. Note that 23 other groups may also distribute working documents as Internet- 24 Drafts. 26 Internet-Drafts are draft documents valid for a maximum of six 27 months and may be updated, replaced, or obsoleted by other 28 documents at any time. It is inappropriate to use Internet-Drafts 29 as reference material or to cite them other than as "work in 30 progress." 32 The list of current Internet-Drafts can be accessed at 33 http://www.ietf.org/ietf/1id-abstracts.txt 35 The list of Internet-Draft Shadow Directories can be accessed at 36 http://www.ietf.org/shadow.html 38 This Internet-Draft will expire on August 3, 2006. 40 Copyright Notice 42 Copyright (C) The Internet Society (2006). All Rights Reserved. 44 Abstract 46 A Mobile IPv6 node requires a Home Agent address, a home address, 47 and IPsec security associations with its Home Agent before it can 48 start utilizing Mobile IPv6 service. RFC 3775 requires that some 49 or all of these are statically configured. This document defines 50 how a Mobile IPv6 node can bootstrap this information from non- 51 topological information and security credentials preconfigured on 52 the Mobile Node. The solution defined in this document solves the 53 bootstrapping problem from draft-ietf-mip6-bootstrapping-ps-02 54 when the Mobile Node's mobility service is authorized by a 55 different service provider than basic network access, and is 56 therefore generically applicable to any bootstrapping case. 58 Conventions used in this document 60 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL 61 NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" 62 in this document are to be interpreted as described in RFC-2119 63 [1]. 65 Table of Contents 67 1. Introduction...................................................4 68 2. Terminology....................................................5 69 3. Split scenario.................................................6 70 4. Components of the solution.....................................9 71 5. Protocol Operations...........................................11 72 5.1. Home Agent Address Discovery.............................11 73 5.1.1. DNS lookup by Home Agent Name.......................11 74 5.1.2. DNS lookup by service name..........................12 75 5.2. IPsec Security Associations setup........................13 76 5.3. Home Address assignment..................................13 77 5.3.1. Home Address assignment by the Home Agent...........13 78 5.3.2. Home Address auto-configuration by the Mobile Node..13 79 5.4. Authorization and Authentication with MSA................15 80 6. Home Address registration in the DNS..........................17 81 7. Summary of Bootstrapping Protocol Flow........................19 82 8. Option and Attribute Format...................................21 83 8.1. DNS Update mobility option...............................21 84 8.2. MIP6_HOME_PREFIX attribute...............................22 85 9. Security Considerations.......................................23 86 9.1. HA Address Discovery.....................................23 87 9.2. Home Address Assignment through IKEv2....................24 88 9.3. SA Establishment Using EAP Through IKEv2.................25 89 9.4. Back End Security Between the HA and AAA Server..........25 90 9.5. Dynamic DNS Update.......................................25 91 10. IANA Considerations..........................................27 92 11. Contributors.................................................28 93 12. Acknowledgments..............................................29 94 12.1. Normative References....................................30 95 12.2. Informative References..................................30 96 Authors' Addresses...............................................32 97 Intellectual Property Statement..................................33 98 Disclaimer of Validity...........................................33 99 Copyright Statement..............................................33 100 Acknowledgment...................................................33 102 1. Introduction 104 Mobile IPv6 [2] requires the Mobile Node to know its Home Agent 105 Address, its own Home Address and the cryptographic materials 106 (e.g. shared keys or certificates) needed to set up IPsec security 107 associations with the Home Agent in order to protect Mobile IPv6 108 signaling. This is generally referred to as the Mobile IPv6 109 bootstrapping problem [4]. 111 Mobile IPv6 base protocol does not specify any method to 112 automatically acquire this information, which means that network 113 administrators are normally required to manually set configuration 114 data on Mobile Nodes and HAs. However, in real deployments, manual 115 configuration does not scale as the Mobile Nodes increase in 116 number. 118 As discussed in [4], several bootstrapping scenarios can be 119 identified depending on the relationship between the network 120 operator that authenticates a mobile node for granting network 121 access service (Access Service Authorizer, ASA) and the service 122 provider that authorizes Mobile IPv6 service (Mobility Service 123 Authorizer, MSA). This document describes a solution to the 124 bootstrapping problem that is applicable in a scenario where the 125 MSA and the ASA are different entities (i.e. split scenario). 127 2. Terminology 129 General mobility terminology can be found in [8]. The following 130 additional terms are used here: 132 ASA 133 Access Service Authorizer. A network operator that 134 authenticates a mobile node and establishes the mobile node's 135 authorization to receive Internet service. 137 ASP 138 Access Service Provider. A network operator that provides 139 direct IP packet forwarding to and from the end host. 141 MSA 142 Mobility Service Authorizer. A service provider that 143 authorizes Mobile IPv6 service. 145 MSP 146 Mobility Service Provider. A service provider that provides 147 Mobile IPv6 service. In order to obtain such service, the 148 mobile node must be authenticated and prove authorization to 149 obtain the service. 151 Split scenario 152 A scenario where mobility service and network access service 153 are authorized by different entities. This implies that MSA is 154 different from ASA. 156 3. Split scenario 158 In the problem statement description [4] there is a clear 159 assumption that mobility service and network access service can be 160 separate. This assumption implies that mobility service and 161 network access service may be authorized by different entities. As 162 an example, the service model defined in [4] allows an enterprise 163 network to deploy a Home Agent and offer Mobile IPv6 service to a 164 user, even if the user is accessing the Internet independent of 165 its enterprise account (e.g., by using his personal WiFi hotspot 166 account at a coffee shop). 168 Therefore, in this document it is assumed that network access and 169 mobility service are authorized by different entities, which means 170 that authentication and authorization for mobility service and 171 network access will be considered separately. This scenario is 172 called split scenario. 174 Moreover, the model defined in [4] separates the entity providing 175 the service from the entity that authenticates and authorizes the 176 user. This is similar to the roaming model for network access. 177 Therefore, in the split scenario, two different cases can be 178 identified depending on the relationship between the entity that 179 provides the mobility service (i.e. Mobility Service Provider, 180 MSP) and the entity that authenticates and authorizes the user 181 (i.e. Mobility Service Authorizer, MSA). 183 Figure 1 depicts the split scenario when the MSP and the MSA are 184 the same entity. This means that the network operator that 185 provides the Home Agent authenticates and authorizes the 186 user for mobility service.. 188 Mobility Service 189 Provider and Authorizer 190 +-------------------------------------------+ 191 | | 192 | +-------------+ +--+ | 193 | | MSA/MSP AAA | <-------------> |HA| | 194 | | server | AAA protocol +--+ | 195 | +-------------+ | 196 | | 197 +-------------------------------------------+ 199 +--+ 200 |MN| 201 +--+ 203 Figure 1 - Split Scenario (MSA == MSP) 205 Figure 2 shows the split scenario in case the MSA and the MSP are 206 two different entities. This might happen if the Mobile Node is 207 far from its MSA network and is assigned a closer HA to optimize 208 performance or if the MSA cannot provide any Home Agent and relies 209 on a third party (i.e. the MSP) to grant mobility service to its 210 users. Notice that the MSP might be or might not also be the 211 network operator that is providing network access (i.e. ASP, 212 Access Service Provider). 214 Mobility Service 215 Authorizer 216 +-------------+ 217 | MSA AAA | 218 | server | 219 +-------------+ 220 ^ 221 | 222 AAA protocol | 223 | Mobility Service 224 | Provider 225 +--------|----------------------------------+ 226 | V | 227 | +-------------+ +--+ | 228 | | MSP AAA | <-------------> |HA| | 229 | | server | AAA protocol +--+ | 230 | +-------------+ | 231 | | 232 +-------------------------------------------+ 234 +--+ 235 |MN| 236 +--+ 238 Figure 2 - Split Scenario (MSA != MSP) 240 Note that Figure 1 and Figure 2 assume the use of an AAA protocol 241 to authenticate and authorize the Mobile Node for mobility 242 service. However, since IKEv2 allows EAP client authentication 243 only and the server authentication needs to be performed based on 244 certificates or public keys, the Mobile Node potentially requires 245 a certificate revocation list check (CTL check) even though an AAA 246 potocol is used to authenticate and authorize the Mobile Node for 247 mobility service. 249 If, instead, a PKI is used, the Mobile Node and HA exchange 250 certificates and there is no AAA server involved. This is 251 conceptually similar to Figure 1, since the MSP == MSA, except the 252 Home Agent, and potentially the Mobile Node, may require a 253 certificate revocation list check (CRL check) with the Certificate 254 Authority (CA). The CA may be either internal or external to the 255 MSP. Figure 3 illustrates. 257 Certificate 258 Authority 259 +-------------+ 260 | CA | 261 | server | 262 +-------------+ 263 ^ 264 | 265 CRL Check | 266 | Mobility Service 267 | Provider and Authorizer 268 +--------|----------+ 269 | V | 270 | +-------------+ | 271 | | HA | | 272 | | | | 273 | +-------------+ | 274 | | 275 +-------------------+ 277 +--+ 278 |MN| 279 +--+ 281 Figure 3 - Split Scenario with PKI 283 The split scenario is the simplest model that can be identified, 284 since no assumptions about the access network are made. This 285 implies that the mobility service is bootstrapped independently 286 from the authentication protocol for network access used (e.g. 287 PANA, EAP). For this reason, the solution described in this 288 document and developed for this scenario could also be applied to 289 the integrated access network deployment model [4], even if it 290 might not be optimized. 292 4. Components of the solution 294 The bootstrapping problem is composed of different sub-problems 295 that can be solved independently in a modular way. The components 296 identified and a brief overview of their solution follow. 298 o HA address discovery. The Mobile Node needs to discover the 299 address of its Home Agent. The main objective of a 300 bootstrapping solution is to minimize the data pre-configured 301 on the Mobile Node. For this reason, the DHAAD defined in [2] 302 may not be applicable in real deployments since it is required 303 that the Mobile Node is pre-configured with the home network 304 prefix and it does not allow an operator to load balance by 305 having Mobile Nodes dynamically assigned to Home Agents located 306 in different subnets. This document defines a solution for Home 307 Agent address discovery that is based on Domain Name Service 308 (DNS), introducing a new DNS SRV record [5]. The unique 309 information that needs to be pre-configured on the Mobile Node 310 is the domain name of the MSP. 312 o IPsec Security Associations setup. Mobile IPv6 requires that a 313 Mobile Node and its Home Agent share an IPsec SA in order to 314 protect binding updates and other Mobile IPv6 signaling. This 315 document provides a solution that is based on IKEv2 and follows 316 what is specified in [6]. The IKEv2 peer authentication can be 317 performed both using certificates and using EAP, depending on 318 the network operator's deployment model. 320 o Home Address (HoA) assignment. The Mobile Node needs to know 321 its Home Address in order to bootstrap Mobile IPv6 operation. 322 The Home Address is assigned by the Home Agent during the IKEv2 323 exchange (as described in [6]). The solution defined in this 324 document also allows the Mobile Node to auto-configure its Home 325 Address based on stateless auto-configuration ([20]), 326 Cryptographically Generated Addresses ([9]) or privacy 327 addresses ([10]). 329 o Authentication and Authorization with MSA. The user must be 330 authenticated in order for the MSP to grant the service. Since 331 the user credentials can be verified only by the MSA, this 332 authorization step is performed by the MSA. Moreover, the 333 mobility service must be explicitly authorized by the MSA based 334 on the user's profile. These operations are performed in 335 different ways depending on the credentials used by the Mobile 336 Node during the IKEv2 peer authentication and on the backend 337 infrastructure (PKI or AAA). 339 An optional part of bootstrapping involves providing a way for the 340 Mobile Node to have its FQDN updated in the DNS with a dynamically 341 assigned home address. While not all applications will require 342 this service, many networking applications use the FQDN to obtain 343 an address for a node prior to starting IP traffic with it. The 344 solution defined in this document specifies that the dynamic DNS 345 update is performed by the Home Agent or through the AAA 346 infrastructure, depending on the trust relationship in place. 348 5. Protocol Operations 350 This section describes in detail the procedures needed to perform 351 Mobile IPv6 bootstrapping based on the components identified in 352 the previous section. 354 5.1. Home Agent Address Discovery 356 Once a Mobile Node has obtained network access, it can perform 357 Mobile IPv6 bootstrapping. For this purpose, the Mobile Node 358 queries the DNS server to request information on Home Agent 359 service. As mentioned before in the document, the only information 360 that needs to be pre-configured on the Mobile Node is the domain 361 name of the Mobility Service Provider. 363 The Mobile Node needs to obtain the IP address of the DNS server 364 before it can send a DNS request. This can be pre-configured on 365 the Mobile Node or obtained through DHCPv6 from the visited link 366 [11]. In any case, it is assumed that there is some kind of 367 mechanism by which the Mobile Node is configured with a DNS server 368 since a DNS server is needed for many other reasons. 370 Two options for DNS lookup for a Home Agent address are identified 371 in this document: DNS lookup by Home Agent Name and DNS lookup by 372 service name. 374 This document does not provide a specific mechanism to load balance different 375 Mobile Nodes among Home Agents. It is possible for an MSP to achieve coarse- 376 grained load balancing by dynamically updating the SRV RR priorities to reflect 377 the current load on the MSP's collection of Home Agents. Mobile Nodes then use 378 the priority mechanism to preferentially select the least loaded HA. The 379 effectiveness of this technique depends on how much of a load it will place on 380 the DNS servers, particularly if dynamic DNS is used for frequent updates. 382 While this document specifies a Home Agent Address Discovery 383 solution based on DNS, when the ASP and the MSP are the same 384 entity DHCP may be used. See [15] for details. 386 5.1.1. DNS lookup by Home Agent Name 388 In this case, the Mobile Node is configured with the Fully 389 Qualified Domain Name of the Home Agent. As an example, the Mobile 390 Node could be configured with the name "ha1.example.com", where 391 "example.com" is the domain name of the MSP granting the mobility 392 service. 394 The Mobile Node constructs a DNS request, by setting the QNAME to 395 the name of the Home Agent. The request has QTYPE set to 'AAAA', 396 so that the DNS server sends the IPv6 address of the Home Agent. 398 Once the DNS server replies to this query, the Mobile Node knows 399 its Home Agent address and can run IKEv2 in order to set up the 400 IPsec SAs and get a Home Address. 402 Additionally, the ability to provide a mobile node with a 403 localized home agent (e.g. on the visited link) can help to 404 optimize handover signaling and improve routing efficiency in bi- 405 directional tunneling mode. There are a variety of ways this can 406 be achieved in an interoperable way. One way is to provision the 407 mobile node with an FQDN for a local home agent when it configures 408 for the local link. Another way is to specify an interoperable 409 naming convention for constructing home agent FQDNs based on 410 location. For example, an operator might assign the FQDN 411 "ha.locationA.operator.com" to the Home Agent located in "location 412 A" and the FQDN "ha.locationB.operator.com" to the Home Agent 413 located in "location B". If the Mobile Node wants to use a Home 414 Agent located in "location A", it will set the QNAME to 415 "ha.locationA.operator.com" in the DNS request. The exact way in 416 which localized Home Agents are configured is out of scope for 417 this draft. 419 5.1.2. DNS lookup by service name 421 RFC 2782 [5] defines the service resource record (SRV RR) that 422 allows an operator to use several servers for a single domain, to 423 move services from host to host, and to designate some hosts as 424 primary servers for a service and others as backups. Clients ask 425 for a specific service/protocol for a specific domain and get back 426 the names of any available servers. 428 RFC 2782[5] also describes the policies to choose a service agent 429 based on the preference and weight values. The DNS SRV record may 430 contain the preference and weight values for multiple Home Agents 431 available to the Mobile Node in addition to the Home Agent FQDNs. 432 If multiple Home Agents are available in the DNS SRV record then 433 Mobile Node is responsible for processing the information as per 434 policy and for picking one Home Agent. If the Home Agent of choice 435 does not respond for some reason or the IKEv2 authentication 436 fails, the Mobile Node SHOULD try other Home Agents on the list. 438 The service name for Mobile IPv6 Home Agent service as required by 439 RFC 2782 is "mip6" and the protocol name is "ipv6". Note that a 440 transport name cannot be used here because Mobile IPv6 does not 441 run over a transport protocol. 443 The SRV RR has a DNS type code of 33. As an example, the Mobile 444 constructs a request with QNAME set to "_mip6._ipv6.example.com" 445 and QTYPE to SRV. The reply contains the FQDNs of one or more 446 servers, that can then be resolved in a separate DNS transaction 447 to the IP addresses. However, if there is room in the SRV reply, 448 it is RECOMMENDED that the DNS server also return the IP addresses 449 of the Home Agents in AAAA records as part of the additional data 450 section (in order to avoid requiring an additional DNS round trip 451 to resolve the FQDNs). 453 5.2. IPsec Security Associations setup 455 As soon as the Mobile Node has discovered the Home Agent Address, 456 it establishes an IPsec Security Association with the Home Agent 457 itself through IKEv2. The detailed description of this procedure 458 is provided in [6]. If the Mobile Node wants the HA to register 459 the Home Address in the DNS, it MUST use the FQDN as the initiator 460 identity in IKE_AUTH step of the IKEv2 exchange (IDi). This is 461 needed because the Mobile Node has to provide it is the owner of 462 the FQDN provided in the subsequent DNS Update Option. See section 463 6 and section 9 for a more detailed analysis on this issue. 465 The IKEv2 Mobile Node to Home Agent authentication can be 466 performed using either IKEv2 public key signatures or the 467 Extensible Authentication Protocol (EAP). The details about how to 468 use IKEv2 authentication are described in [6] and [7]. Choice of 469 an IKEv2 peer authentication method depends on the deployment. 470 However, IKEv2 restricts the Home Agent to Mobile Node 471 authentication to use public key signature-based authentication. 473 5.3. Home Address assignment 475 Home Address assignment is performed during the IKEv2 exchange. 476 The Home Address can be assigned directly by the Home Agent or can 477 be auto-configured by the Mobile Node. 479 5.3.1. Home Address assignment by the Home Agent 481 When the Mobile Node runs IKEv2 with its Home Agent, it can 482 request a HoA through the Configuration Payload in the IKE_AUTH 483 exchange by including an INTERNAL_IP6_ADDRESS attribute. When the 484 Home Agent processes the message, it allocates a HoA and sends it 485 a CFG_REPLY message. The Home Agent could consult a DHCP server on 486 the home link for the actual home address allocation. This is 487 explained in detail in [6]. 489 5.3.2. Home Address auto-configuration by the Mobile Node 491 With the type of assignment described in the previous section, the 492 Home Address cannot be generated based on Cryptographically 493 Generated Addresses (CGAs) [9] or based on the privacy extensions 494 for stateless auto-configuration [10]. However, the Mobile Node 495 might want to have an auto-configured HoA based on these 496 mechanisms. It is worthwhile to mention that the auto- 497 configuration procedure described in this section cannot be used 498 in some possible deployments, since the Home Agents might be 499 provisioned with pools of allowed Home Addresses. 501 In the simplest case, the Mobile Node is provided with a pre- 502 configured home prefix and home prefix length. In this case the 503 Mobile Node creates a Home Address based on the pre-configured 504 prefix and sends it to the Home Agent including an 505 INTERNAL_IP6_ADDRESS attribute in a Configuration Payload of type 506 CFG_REQUEST. If the Home Address is valid, the Home Agent replies 507 with a CFG_REPLY, including an INTERNAL_IP6_ADDRESS with the same 508 address. If the Home Address provided by the Mobile Node is not 509 valid, the Home Agent assigns a different Home Address including 510 an INTERNAL_IP6_ADDRESS attribute with a new value. According to 511 [7] the Mobile Node MUST use the address sent by the Home Agent. 512 Later, if the Mobile Node wants to use an auto-configured Home 513 Address (e.g. based on CGA), it can run Mobile Prefix Discovery, 514 obtain a prefix, auto-configure a new Home Address and then 515 perform a new CREATE_CHILD_SA exchange. 517 If the Mobile Node is not provided with a pre-configured Home 518 Prefix, the Mobile cannot simply propose an auto-configured HoA in 519 the Configuration Payload since the Mobile Node does not know the 520 home prefix before the start of the IKEv2 exchange. The Mobile 521 Node must obtain the home prefix and the home prefix length before 522 it can configure a home address. 524 One simple solution would be for the Mobile Node to just assume 525 that the prefix length on the home link is 64 bits and extract the 526 home prefix from the Home Agent's address. The disadvantage with 527 this solution is that the home prefix cannot be anything other 528 than /64. Moreover, this ties the prefix on the home link and the 529 Home Agent's address, but, in general, a Home Agent with a 530 particular address should be able to serve a number of prefixes on 531 the home link, not just the prefix from which its address is 532 configured. 534 Another solution would be for the Mobile Node to assume that the 535 prefix length on the home link is 64 bits and send its interface 536 identifier to the Home Agent in the INTERNAL_IP6_ADDRESS attribute 537 within the CFG_REQ payload. Even though this approach does not tie 538 the prefix on the home link and the Home Agent's address, it still 539 requires that the home prefix length is 64 bits. 541 For this reason the Mobile Node needs to obtain the home link 542 prefixes through the IKEv2 exchange. In the Configuration Payload 543 during the IKE_AUTH exchange, the Mobile Node includes the 544 MIP6_HOME_PREFIX attribute in the CFG_REQUEST message. The Home 545 Agent, when it processes this message, should include in the 546 CFG_REPLY payload prefix information for one prefix on the home 547 link. This prefix information includes the prefix length (see 548 section 8.2). The Mobile Node auto-configures a Home Address from 549 the prefix returned in the CFG_REPLY message and runs a 550 CREATE_CHILD_SA exchange to create security associations for the 551 new Home Address. 553 As mentioned before in this document, there are deployments where 554 auto-configuration of the Home Address cannot be used. In this 555 case, when the Home Agent receives a CFG_REQUEST including a 556 MIP6_HOME_PREFIX attribute, in the subsequent IKE response it 557 includes a Notify Payload type "USE_ASSIGNED_HoA" and the related 558 Home Address in a INTERNAL_IP6_ADDRESS attribute. If the Mobile 559 Node gets a "USE_ASSIGNED_HoA" Notify Payload in response to the 560 Configuration Payload containing the MIP6_HOME_PREFIX attribute, 561 it looks for an INTERNAL_IP6_ADDRESS attribute and MUST use the 562 address contained in it in the subsequent CREATE_CHILD_SA 563 exchange. 565 When the Home Agent receives a Binding Update for the Mobile Node, 566 it performs proxy DAD for the auto-configured Home Address. If DAD 567 fails, the Home Agent rejects the Binding Update. If the Mobile 568 Node receives a Binding Acknowledgement with status 134 (DAD 569 failed), it MUST stop using the current Home Address, configure a 570 new HoA, and then run IKEv2 CREATE_CHILD_SA exchange to create 571 security associations based on the new HoA. The Mobile Node does 572 not need to run IKE_INIT and IKE_AUTH exchanges again. Once the 573 necessary security associations are created, the Mobile Node sends 574 a Binding Update for the new Home Address. 576 It is worth noting that with this mechanism, the prefix 577 information carried in MIP6_HOME_PREFIX attribute includes only 578 one prefix and does not carry all the information that is 579 typically present when received through a IPv6 router 580 advertisement. Mobile Prefix Discovery, specified in RFC 3775 [2], 581 is the mechanism through which the Mobile Node can get all 582 prefixes on the home link and all related information. That means 583 that MIP6_HOME_PREFIX attribute is only used for Home Address 584 auto-configuration and does not replace the usage of Mobile Prefix 585 Discovery for the purposes detailed in RFC 3775. 587 5.4. Authorization and Authentication with MSA 589 In a scenario where the Home Agent is discovered dynamically by 590 the Mobile Node, it is very likely that the Home Agent is not able 591 to verify by its own the credentials provided by the Mobile Node 592 during the IKEv2 exchange. Moreover, the mobility service needs to 593 be explicitly authorized based on the user's profile. As an 594 example, the Home Agent might not be aware of whether the mobility 595 service can be granted at a particular time of the day or when the 596 credit of the Mobile Node is going to expire. 598 Due to all these reasons, the Home Agent may need to contact the 599 MSA in order to authenticate the Mobile Node and authorize 600 mobility service. This can be accomplished based on a Public Key 601 Infrastructure if certificates are used and a PKI is deployed by 602 the MSP and MSA. On the other hand, if the Mobile Node is provided 603 with other types of credentials, the AAA infrastructure must be 604 used. 606 The definition of this backend communication is out of the scope 607 of this document. In [12] a list of goals for such a communication 608 is provided. 610 6. Home Address registration in the DNS 612 In order that the Mobile Node is reachable through its dynamically 613 assigned Home Address, the DNS needs to be updated with the new 614 Home Address. Since applications make use of DNS lookups on FQDN 615 to find a node, the DNS update is essential for providing IP 616 reachability to the Mobile Node, which is the main purpose of the 617 Mobile IPv6 protocol. The need for DNS updating is not discussed 618 in RFC 3775 since it assumes that the Mobile Node is provisioned 619 with a static Home Address. However, when a dynamic Home Address 620 is assigned to the Mobile Node, any existing DNS entry becomes 621 invalid and the Mobile Node becomes unreachable unless a DNS 622 update is performed. 624 Since the DNS update must be performed securely in order to 625 prevent attacks or modifications from malicious nodes, the node 626 performing this update must share a security association with the 627 DNS server. Having all possible Mobile Nodes sharing a security 628 association with the DNS servers of the MSP might be cumbersome 629 from an administrative perspective. Moreover, even if a Mobile 630 Node has a security association with a DNS server of its MSP, an 631 address authorization issue comes into the picture. A detailed 632 analysis of possible threats against DNS update is provided in 633 section 9.5. 635 Therefore, due to security and administrative reasons, it is 636 RECOMMENDED that the Home Agent perform DNS entry updates for the 637 Mobile Node. For this purpose the Mobile Node MAY include a new 638 mobility option in the Binding Update, the DNS Update option, with 639 the flag R not set in the option. This option is defined in 640 section 8 and includes the FQDN that needs to be updated. After 641 receiving the Binding Update, the Home Agent MUST update the DNS 642 entry with the identifier provided by the Mobile Node and the Home 643 Address included in the Home Address Option. The procedure for 644 sending a dynamic DNS update message is specified in [14]. The 645 dynamic DNS update SHOULD be performed in a secure way; for this 646 reason, the usage of TKEY and TSEC or DNSSEC is recommended (see 647 section 9.5. for details). As soon as the Home Agent has updated 648 the DNS, it MUST send a Binding Acknowledgement message to the 649 Mobile Node including the DNS Update mobility option with the 650 correct value in the Status field (see section 8.1). 652 This procedure can be performed directly by the Home Agent if the 653 Home Agent has a security association with the domain specified in 654 the Mobile Node's FQDN. 656 On the other hand, if the Mobile Node wants to be reachable 657 through a FQDN that belongs to the MSA, the Home Agent and the DNS 658 server that must be updated belong to different administrative 659 domains. In this case the Home Agent may not share a security 660 association with the DNS server and the DNS entry update can be 661 performed by the AAA server of the MSA. In order to accomplish 662 this, the Home Agent sends to the AAA server the FQDN-HoA pair 663 through the AAA protocol. This message is proxied by the AAA 664 infrastructure of the MSP and is received by the AAA server of the 665 MSA. The AAA server of the MSA perform the DNS update based on 666 [14]. Notice that, even in this case, the Home Agent is always 667 required to perform a DNS update for the reverse entry, since this 668 is always performed in the DNS server of the MSP. The detailed 669 description of the communication between Home Agent and AAA is out 670 of the scope of this document. More details are provided in [12]. 672 A mechanism to remove stale DNS entries is needed. A DNS entry 673 becomes stale when the related Home Address is no longer used by 674 the Mobile Node. To remove a DNS entry, the Mobile Node includes 675 in the Binding Update the DNS Update mobility option, with the 676 flag R set in the option. After receiving the Binding Update, the 677 Home Agent MUST remove the DNS entry identified by the FQDN 678 provided by the Mobile Node and the Home Address included in the 679 Home Address Option. The procedure for sending a dynamic DNS 680 update message is specified in [14]. As mentioned above, the 681 dynamic DNS update SHOULD be performed in a secure way; for this 682 reason, the usage of TKEY and TSEC or DNSSEC is recommended (see 683 section 9.5. for details). 685 This approach does not work if the Mobile Node stops using the 686 Home Address without sending a Binding Update message (e.g. in 687 case of crash). In this case, an additional mechanism to trigger 688 the DNS entry removal is needed. For this purpose, the Home Agent 689 has a timer related to the DNS entry of the Mobile Node. This 690 timer is initialized when the Mobile Node sends a Binding Update 691 with R==0 (i.e. when the Mobile Node asks the Home Agent to bind 692 the FQDN to the Home Address). The initial value of this timer is 693 configurable by the network operator. 695 If the Home Agent receives a Binding Update with R==1, it removes 696 the DNS entry as described in the previous paragraph and removes 697 the timer associated with that entry. If the timer expires without 698 receiving a Binding Update with R==1, the HA checks the Binding 699 Cache. If there is an existing Binding Cache entry for the HoA, 700 the HA does not remove the DNS entry and re-initialize the timer. 701 If there is not a Binding Cache entry, it sends a Neighbor 702 Solicitation message to check if the Mobile Node is at home and is 703 using the HoA. If the HA gets a Neighbor Advertisement message, it 704 does not remove the DNS entry and re-initialize the timer. If it 705 does not receive a NA, it removes the DNS entry and the timer 706 associated with it. 708 7. Summary of Bootstrapping Protocol Flow 710 The message flow of the whole bootstrapping procedure when the 711 dynamic DNS update is performed by the Home Agent is depicted in 712 Figure 4. 714 +----+ +----+ +-----+ 715 | MN | | HA | | DNS | 716 +----+ +----+ +-----+ 718 IKEv2 exchange 719 (HoA configuration) 720 <======================> 722 BU (DNS update option) 723 -----------------------> 724 DNS update 725 <-------------------> 726 BA (DNS update option) 727 <----------------------- 729 Figure 4 - Dynamic DNS update by the HA 731 Figure 5 shows the message flow of the whole bootstrapping 732 procedure when the dynamic DNS update is performed by the AAA 733 server of the MSA. 735 +----+ +----+ +---+ +---+ 736 | MN | | HA | |AAA| |DNS| 737 +----+ +----+ +---+ +---+ 739 IKEv2 exchange 740 (HoA configuration) 741 <======================> 743 BU (DNS update option) 744 -----------------------> 746 AAA request 747 (FQDN, HoA) 748 <--------------> 750 DNS update 751 <-----------> 752 AAA answer 753 (FQDN, HoA) 754 <--------------> 755 BA (DNS update option) 756 <----------------------- 758 Figure 5 - Dynamic DNS update by the AAA 760 Notice that, even in this last case, the Home Agent is always 761 required to perform a DNS update for the reverse entry, since this 762 is always performed in the DNS server of the MSP. This is not 763 depicted in Figure 5. 765 8. Option and Attribute Format 767 8.1. DNS Update mobility option 769 0 1 2 3 770 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 771 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 772 | Option Type | Option Length | 773 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 774 | Status |R| Reserved | MN identity (FQDN) ... 775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 777 o Option Type - DNS-UPDATE-TYPE to be defined by IANA 779 o Option Length - 8 bit unsigned integer indicating the length of 780 the option excluding the type and length fields 782 o Status - 8 bit unsigned integer indicating the result of the 783 dynamic DNS update procedure. This field MUST be set to 0 and 784 ignored by the receiver when the DNS Update mobility option is 785 included in a Binding Update message. When the DNS Update 786 mobility option is included in the Binding Acknowledgement 787 message, values of the Status field less than 128 indicate that 788 the dynamic DNS update was performed successfully by the Home 789 Agent. Values greater than or equal to 128 indicate that the 790 dynamic DNS update was not completed by the HA. The following 791 Status values are currently defined: 793 0 DNS update performed 795 128 Reason unspecified 797 129 Administratively prohibited 799 130 DNS Update Failed 801 o R flag - if set the Mobile Node is requesting the HA to remove 802 the DNS entry identified by the FQDN specified in this option 803 and the HoA of the Mobile Node. If not set, the Mobile Node is 804 requesting the HA to create or update a DNS entry with its HoA 805 and the FQDN specified in the option. 807 o Reserved - these bits are reserved for future purposes and MUST 808 be set to 0. 810 o MN identity - the identity of the Mobile Node to be used by the 811 Home Agent to send a Dynamic DNS update. It is a variable 812 length field. 814 8.2. MIP6_HOME_PREFIX attribute 816 The MIP6_HOME_PREFIX attribute is included in the IKEv2 817 CFG_REQUEST by the Mobile Node to ask the Home Agent for the home 818 prefix and is included in the CFG_REPLY by the Home Agent to 819 provide the Mobile Node with home prefix and home prefix length. 820 The format of this attribute is equal to the format of the 821 Configuration Attributes defined in [7] and is depicted below. 823 1 2 3 824 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 825 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 826 |R| Attribute Type ! Length | 827 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 828 | | 829 | home prefix | 830 | | 831 | | 832 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 833 | Prefix Lifetime | 834 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 835 | Prefix Length | 836 +-+-+-+-+-+-+-+-+ 838 o Reserved (1 bit) - This bit MUST be set to zero and MUST be 839 ignored on receipt. 841 o Attribute Type (7 bits) - A unique identifier for the 842 MIP6_HOME_PREFIX attribute. To be assigned by IANA. 844 o Length (2 octets) - Length in octets of Value field (home 845 prefix and Prefix Length). This is multi-valued and can be 0 or 846 17. 848 o Home Prefix (16 octets) - The prefix of the home link through 849 which the Mobile Node must auto-configure its Home Address. 851 o Prefix Lifetime (4 octets) - 853 o Prefix Length (1 octet) - The length in bits of the home prefix 854 specified in the field Home Prefix. 856 When the MIP6_HOME_PREFIX attribute is included by the Mobile Node 857 in the CFG_REQUEST payload, the value of the Length field is 0. On 858 the other hand, when the MIP6_HOME_PREFIX attribute is included in 859 the CFG_REPLY payload by the Home Agent, the value of the Length 860 field is 17 and the attribute contains also the Home Prefix and 861 the Prefix Length fields. 863 9. Security Considerations 865 9.1. HA Address Discovery 867 Use of DNS for address discovery carries certain security risks. 868 DNS transactions in the Internet are typically done without any 869 authentication of the DNS server by the client or of the client by 870 the server. There are two risks involved: 872 1) A legitimate client obtains a bogus Home Agent address from a 873 bogus DNS server. This is sometimes called a "pharming" attack, 875 2) An attacking client obtains a legitimate Home Agent address 876 from a legitimate server. 878 The risk in Case 1 is mitigated because the Mobile Node is 879 required to conduct an IKE transaction with the Home Agent prior 880 to performing a Binding Update to establish Mobile IPv6 service. 881 According to the IKEv2 specification [7], the responder must 882 present the initiator with a valid certificate containing the 883 responder's public key, and the responder to initiator IKE_AUTH 884 message must be protected with an authenticator calculated using 885 the public key in the certificate. Thus, an attacker would have to 886 set up both a bogus DNS server and a bogus Home Agent, and 887 provision the Home Agent with a certificate that a victim Mobile 888 Node could verify. If the Mobile Node can detect that the 889 certificate is not trustworthy, the attack will be foiled when the 890 Mobile Node attempts to set up the IKE SA. 892 The risk in Case 2 is limited for a single Mobile Node to Home 893 Agent transaction if the attacker does not possess proper 894 credentials to authenticate with the Home Agent. The IKE SA 895 establishment will fail when the attacking Mobile Node attempts to 896 authenticate itself with the Home Agent. Regardless of whether the 897 Home Agent utilizes EAP or host-side certificates to authenticate 898 the Mobile Node, the authentication will fail unless the Mobile 899 Node has valid credentials. 901 Another risk exists in Case 2 because the attacker may be 902 attempting to propagate a DoS attack on the Home Agent. In that 903 case, the attacker obtains the Home Agent address from the DNS, 904 then propagates the address to a network of attacking hosts that 905 bombard the Home Agent with traffic. This attack is not unique to 906 the bootstrapping solution, however, it is actually a risk that 907 any Mobile IPv6 Home Agent installation faces. In fact, the risk 908 is faced by any service in the Internet that distributes a unicast 909 globally routable address to clients. Since Mobile IPv6 requires 910 that the Mobile Node communicate through a globally routable 911 unicast address of a Home Agent, it is possible that the Home 912 Agent address could be propagated to an attacker by various means 913 (theft of the Mobile Node, malware installed on the Mobile Node, 914 evil intent of the Mobile Node owner him/herself, etc.) even if 915 the home address is manually configured on the Mobile Node. 916 Consequently, every Mobile IPv6 Home Agent installation will 917 likely be required to mount anti-DoS measures. Such measures 918 include overprovisioning of links to and from Home Agents and of 919 Home Agent processing capacity, vigilant monitoring of traffic on 920 the Home Agent networks to detect when traffic volume increases 921 abnormally indicating a possible DoS attack, and hot spares that 922 can quickly be switched on in the event an attack is mounted on an 923 operating collection of Home Agents. DoS attacks of moderate 924 intensity should be foiled during the IKEv2 transaction. IKEv2 925 implementations are expected to generate their cookies without any 926 saved state, and to time out cookie generation parameters 927 frequently, with the timeout value increasing if a DoS attack is 928 suspected. This should prevent state depletion attacks, and should 929 assure continued service to legitimate clients until the practical 930 limits on the network bandwith and processing capacity of the Home 931 Agent network are reached. 933 Explicit security measures between the DNS server and host, such 934 DNSSEC [16] or TSIG/TKEY [17] [18] can mitigate the risk of 1) and 935 2), but these security measures are not widely deployed on end 936 nodes. These security measures are not sufficient to protect the 937 Home Agent address against DoS attack, however, because a node 938 having a legitimate security association with the DNS server could 939 nevertheless intentionally or inadvertently cause the Home Agent 940 address to become the target of DoS. 942 Finally notice that assignment of an home agent from the serving 943 network access provider's (local home agent) or a home agent from 944 a nearby network (nearby home agent) may set up the potential to 945 compromise a mobile node's location privacy. However, since a 946 standardized mechanism of assigning local or nearby home agents is 947 out of scope for this document, it is not possible to present 948 detailed security considerations. Please see other drafts that 949 contain detailed mechanisms for localized home agent assignment, 950 such as [15], for information on the location privacy properties 951 of particular home agent assignment mechanisms. 953 Security considerations for discovering HA using DHCP are covered 954 in draft-jang-dhc-haopt-01 [15]. 956 9.2. Home Address Assignment through IKEv2 958 Mobile IPv6 bootstrapping assigns the home address through the 959 IKEv2 transaction. The Mobile Node can either choose to request an 960 address, similar to DHCP, or the Mobile Node can request a prefix 961 on the home link then auto-configure an address. 963 RFC 3775 [2] and 3776 [3] require that a Home Agent check 964 authorization of a home address received during a Binding Update. 966 The Home Agent MUST set up authorization by linking the home 967 address to the identity of the IPsec SAs used to authenticate the 968 Binding Update message. The linking MUST be done either during the 969 IKE_AUTH phase or CREATE_CHILD_SA phase when the IPsec SAs are 970 constructed. 972 If the address is auto-configured, RFC 3775 requires the Home 973 Agent to proxy-defend the address on the home link after the 974 Mobile Node performs the initial Binding Update. Since it is not 975 currently possible to securely proxy CGAs using SEND, attacks on 976 address resolution for Neighbor Discovery listed in RFC 3756 are 977 possible on dynamically assigned home addresses that are proxied 978 by the Home Agent. 980 9.3. SA Establishment Using EAP Through IKEv2 982 Security considerations for authentication of the IKE transaction 983 using EAP are covered in draft-ietf-mip6-ikev2-ipsec [6]. 985 9.4. Back End Security Between the HA and AAA Server 987 Some deployments of Mobile IPv6 bootstrapping may use an AAA 988 server to handle authorization for mobility service. This process 989 has its own security requirements, but the back end protocol for 990 Home Agent to AAA server interface is not covered in this draft. 991 Please see draft-ietf-mip6-aaa-ha-goals [12] for a discussion of 992 this interface. 994 9.5. Dynamic DNS Update 996 Mobile IPv6 bootstrapping recommends the Home Agent to update the 997 Mobile Node's FQDN with a dynamically assigned home address rather 998 than have the Mobile Node itself do it (see Section 6 above). This 999 choice was motivated by a concern for preventing redirection-based 1000 flooding attacks (see draft-ietf-mip6-ro-sec [19] for more 1001 information about redirection-based flooding attacks and the role 1002 preventing them played in the design of Mobile IPv6 route 1003 optimization security). Exactly as for route optimization, it is 1004 possible for a node that is the legitimate owner of a DNS FQDN - 1005 in the sense that it has a security association with the DNS 1006 server allowing it to perform dynamic DNS update of its FQDN - to 1007 bind its FQDN to the address of a victim, then redirect large 1008 volumes of traffic at the victim. The attack may be propagated 1009 without the owner's knowledge, for example, if the node is 1010 compromised by malware, or it may be intentional if the node 1011 itself is the attacker. 1013 While it is possible to prevent redirection attacks through 1014 ingress filtering on access routers, ISPs have little or no 1015 incentive to deploy ingress filtering. In some cases, if an attack 1016 could result in substantial financial gain, it is even possible 1017 that a corrupt ISP may have an incentive not to deploy ingress 1018 filters such as has been the case for spam. Consequently, the 1019 security for dynamic Mobile Node FQDN update has been assigned to 1020 the Home Agent, where active network administration and vigilant 1021 defense measures are more likely to (but are not assured of) 1022 mitigating problems, and the owner of the Mobile Node is more 1023 likely to detect a problem if it occurs. 1025 If a Home Agent performs dynamic DNS update on behalf of the 1026 Mobile Node directly with the DNS server, the Home Agent MUST have 1027 a security association of some type with the DNS server. The 1028 security association MAY be established either using DNSSEC [16] 1029 or TSIG/TKEY [17][18]. A security association is required even if 1030 the DNS server is in the same administrative domain as the Home 1031 Agent. The security association SHOULD be separate from the 1032 security associations used for other purposes, such as AAA. 1034 In the case where the Mobility Service Provider is different from 1035 the Mobility Service Authorizer, the network administrators may 1036 want to limit the number of cross-administrative domain security 1037 associations. If the Mobile Node's FQDN is in the Mobility Service 1038 Authorizer's domain, since a security association for AAA 1039 signaling involved in mobility service authorization is required 1040 in any case, the Home Agent can send the Mobile Node's FQDN to the 1041 AAA server under the HA-AAA server security association, and the 1042 AAA server can perform the update. In that case, a security 1043 association is required between the AAA server and DNS server for 1044 the dynamic DNS update. See draft-ietf-mip6-aaa-ha-goals [12] for 1045 a deeper discussion of the Home Agent to AAA server interface. 1047 Regardless of whether the AAA server or Home Agent performs DNS 1048 update, the authorization of the Mobile Node to update a FQDN MUST 1049 be checked prior to the performance of the update. It is an 1050 implementation issue as to how authorization is determined. 1051 However, in order to allow this authorization step, the Mobile 1052 Node MUST use a FQDN as the IDi in IKE_AUTH step of the IKEv2 1053 exchange. The FQDN MUST be the same that will be provided by the 1054 Mobile Node in the DNS Update Option. This allows the Home Agent 1055 to get authorization information about the Mobile Node's FQDN via 1056 the AAA back end communication performed during IKEv2 exchange. 1057 The outcome of this step will give the Home Agent the necessary 1058 information to authorize the DNS update request of the Mobile 1059 Node. See draft-ietf-mip6-aaa-ha-goals [12] for details about the 1060 communication between the AAA server and the Home Agent needed to 1061 perform the authorization. Notice that if certificates are used in 1062 IKEv2, the authorization information about the FQDN for DNS update 1063 MUST be present in the certificate provided by the Mobile Node. 1065 10. IANA Considerations 1067 This document defines a new Mobility Option and a new IKEv2 1068 Configuration Attribute Type. 1070 The following values should be assigned: 1072 o from "Mobility Option" namespace ([2]): DNS-UPDATE-TYPE 1073 (section 8.1) 1075 o from "IKEv2 Configuration Payload Attribute Types" namespace 1076 ([7]): MIP6_HOME_PREFIX attribute (section 8.2) 1078 o from "IKEv2 Notify Payload Error Types" namespace ([7]): 1079 USE_ASSIGNED_HoA error type (section 5.3.2) 1081 11. Contributors 1083 This contribution is a joint effort of the bootstrapping solution 1084 design team of the MIP6 WG. The contributors include Basavaraj 1085 Patil, Alpesh Patel, Jari Arkko, James Kempf, Yoshihiro Ohba, 1086 Gopal Dommety, Alper Yegin, Junghoon Jee, Vijay Devarapalli, 1087 Kuntal Chowdury, Julien Bournelle. 1089 The design team members can be reached at: 1091 Gerardo Giaretta gerardo.giaretta@tilab.com 1093 Basavaraj Patil basavaraj.patil@nokia.com 1095 Alpesh Patel alpesh@cisco.com 1097 Jari Arkko jari.arkko@kolumbus.fi 1099 James Kempf kempf@docomolabs-usa.com 1101 Yoshihiro Ohba yohba@tari.toshiba.com 1103 Gopal Dommety gdommety@cisco.com 1105 Alper Yegin alper.yegin@samsung.com 1107 Vijay Devarapalli vijayd@iprg.nokia.com 1109 Kuntal Chowdury kchowdury@starentnetworks.com 1111 Junghoon Jee jhjee@etri.re.kr 1113 Julien Bournelle julien.bournelle@int-evry.fr 1115 12. Acknowledgments 1117 The authors would like to thank Rafa Lopez, Francis Dupont, Jari 1118 Arkko, Kilian Weniger, Vidya Narayanan, Ryuji Wakikawa for their 1119 valuable comments. 1121 13. References 1123 13.1. Normative References 1125 [1] Bradner, S., "Key words for use in RFCs to Indicate 1126 Requirement Levels", BCP 14, RFC 2119, March 1997. 1128 [2] Johnson, D., Perkins, C. and J. Arkko, "Mobility Support 1129 in IPv6�, RFC 3775, June 2004. 1131 [3] Arkko, J., Devarapalli, V., Dupont, F., "Using IPsec to 1132 Protect Mobile IPv6 Signaling between Mobile Nodes and 1133 Home Agents", RFC 3776, June 2004 1135 [4] Patel, A., "Problem Statement for bootstrapping Mobile 1136 IPv6", Internet-Draft draft-ietf-mip6-bootstrap-ps-04, 1137 February 2006. 1139 [5] Gulbrandsen, A., Vixie, P. and L. Esibov, "A DNS RR for 1140 specifying the location of services (DNS SRV)", RFC 2782, 1141 February 2000. 1143 [6] Devarapalli, V., " Mobile IPv6 Operation with IKEv2 and the 1144 revised IPsec Architecture", Internet-Draft draft-ietf-mip6- 1145 ikev2-ipsec-04, October 2005. 1147 [7] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", 1148 RFC 4306, December 2005. 1150 13.2. Informative References 1152 [8] Manner, J., Kojo, M. "Mobility Related Terminology�, RFC 1153 3753, June 2004. 1155 [9] Aura, T., "Cryptographically Generated Addresses (CGA)", RFC 1156 3972, March 2005. 1158 [10] Narten, T., Draves, R., Krishnan, S., "Privacy Extensions 1159 for Stateless Address Autoconfiguration in IPv6", Internet- 1160 Draft draft-ietf-ipv6-privacy-addrs-v2-04, May 2005. 1162 [11] Droms, R., Ed., "DNS Configuration options for Dynamic Host 1163 Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, 1164 December 2003. 1166 [12] Giaretta, G., Ed. "Goals for AAA-HA interface", Internet- 1167 Draft draft-ietf-mip6-aaa-ha-goals-01, February 2006. 1169 [13] Koodli, R., Devarapalli, V., Perkins, C., Flinck, H., 1170 "Solutions for IP Address Location Privacy in the presence 1171 of IP Mobility", Internet-Draft, draft-koodli-mip6-location- 1172 privacy-solutions-00, February 2005. 1174 [14] P. Vixie, Ed., S. Thomson, Y. Rekhter, and J. Bound. 1175 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 1176 RFC 2136, April 1997. 1178 [15] Chowdhury, K., Yegin, A., Choi, J., "MIP6-bootstrapping via 1179 DHCPv6 for the Integrated Scenario", Internet-Draft, draft- 1180 ietf-mip6-bootstrapping-integrated-dhc-00, October 2005. 1182 [16] Arends, R., Austein, R., Larson, M., Massey, D., Rose, S., 1183 "DNS Security Introduction and Requirements", RFC 4033, 1184 March 2005. 1186 [17] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., Wellington, 1187 B., "Secret Key Transaction Authentication for DNS (TSIG)", 1188 RFC 2845, May 2000. 1190 [18] Eastlake 3rd, D., " Secret Key Establishment for DNS (TKEY 1191 RR)", RFC 2930, September 2000. 1193 [19] Nikander, P., Arkko, J., Aura, T., Montenegro, G., 1194 Nordmark, E., "Mobile IP version 6 Route Optimization 1195 Security Design Background", Internet-Draft, draft-ietf- 1196 mip6-ro-sec-02, October 2004. 1198 [20] Narten, T., Nordmark, E., Simpson, W., Soliman, H., 1199 "Neighbor Discovery for IP version 6 (IPv6)"`, Internet- 1200 Draft, draft-ietf-ipv6-2461bis-05, October 2005. 1202 Authors' Addresses 1204 Gerardo Giaretta 1205 Telecom Italia Lab 1206 via Reiss Romoli 274 1207 10148 Torino 1208 Italy 1210 Phone: +39 011 228 6904 1211 Email: gerardo.giaretta@telecomitalia.it 1213 James Kempf 1214 DoCoMo Labs USA 1215 181 Metro Drive 1216 Suite 300 1217 San Jose, CA, 95110 1218 USA 1220 Phone: +1 408 451 4711 1221 Email: kempf@docomolabs-usa.com 1223 Vijay Devarapalli 1224 Nokia Research Center 1225 313 Fairchild Drive 1226 Mountain View, CA 94043 1227 USA 1229 Email: vijay.devarapalli@nokia.com 1231 Intellectual Property Statement 1233 The IETF takes no position regarding the validity or scope of any 1234 Intellectual Property Rights or other rights that might be claimed 1235 to pertain to the implementation or use of the technology 1236 described in this document or the extent to which any license 1237 under such rights might or might not be available; nor does it 1238 represent that it has made any independent effort to identify any 1239 such rights. 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