draft-ietf-mip6-bootstrapping-split-05.txt   draft-ietf-mip6-bootstrapping-split-06.txt 
MIP6 Working Group G. Giaretta, Ed. MIP6 Working Group G. Giaretta, Ed.
Internet-Draft Qualcomm Internet-Draft Qualcomm
Intended status: Standards Track J. Kempf Intended status: Standards Track J. Kempf
Expires: November 26, 2007 DoCoMo Labs USA Expires: January 9, 2008 DoCoMo Labs USA
V. Devarapalli V. Devarapalli, Ed.
Azaire Networks Azaire Networks
May 25, 2007 July 8, 2007
Mobile IPv6 bootstrapping in split scenario Mobile IPv6 bootstrapping in split scenario
draft-ietf-mip6-bootstrapping-split-05 draft-ietf-mip6-bootstrapping-split-06
Status of this Memo Status of this Memo
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This Internet-Draft will expire on November 26, 2007. This Internet-Draft will expire on January 9, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
A Mobile IPv6 node requires a Home Agent address, a home address, and A Mobile IPv6 node requires a Home Agent address, a home address, and
IPsec security associations with its Home Agent before it can start IPsec security associations with its Home Agent before it can start
utilizing Mobile IPv6 service. RFC 3775 requires that some or all of utilizing Mobile IPv6 service. RFC 3775 requires that some or all of
these are statically configured. This document defines how a Mobile these are statically configured. This document defines how a Mobile
IPv6 node can bootstrap this information from non-topological IPv6 node can bootstrap this information from non-topological
information and security credentials preconfigured on the Mobile information and security credentials pre-configured on the Mobile
Node. The solution defined in this document solves the Mobile IPv6 Node. The solution defined in this document solves the split
bootstrapping problem (RFC4640) when the Mobile Node's mobility scenario described in the Mobile IPv6 bootstrapping problem statement
service is authorized by a different service provider than basic in RFC 4640. The split scenario refers the case where the Mobile
network access, and is therefore generically applicable to any Node's mobility service is authorized by a different service provider
bootstrapping case. than basic network access. The solution described in this document
is also generically applicable to any bootstrapping case, since other
scenarios are more specific realizations of the split scenario.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Split scenario . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Split scenario . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Components of the solution . . . . . . . . . . . . . . . . . . 7 4. Components of the solution . . . . . . . . . . . . . . . . . . 7
5. Protocol Operations . . . . . . . . . . . . . . . . . . . . . 9 5. Protocol Operations . . . . . . . . . . . . . . . . . . . . . 9
5.1. Home Agent Address Discovery . . . . . . . . . . . . . . . 9 5.1. Home Agent Address Discovery . . . . . . . . . . . . . . . 9
5.1.1. DNS lookup by Home Agent Name . . . . . . . . . . . . 9 5.1.1. DNS lookup by Home Agent Name . . . . . . . . . . . . 9
5.1.2. DNS lookup by service name . . . . . . . . . . . . . . 10 5.1.2. DNS lookup by service name . . . . . . . . . . . . . . 10
5.1.3. Anycast Address for Home Agent Assignment . . . . . . 11
5.2. IPsec Security Associations setup . . . . . . . . . . . . 11 5.2. IPsec Security Associations setup . . . . . . . . . . . . 11
5.2.1. IKEv2 Transaction with anycast Home Agent 5.3. Home Address assignment . . . . . . . . . . . . . . . . . 11
assignment . . . . . . . . . . . . . . . . . . . . . . 12 5.3.1. Home Address assignment by the Home Agent . . . . . . 11
5.3. Home Address assignment . . . . . . . . . . . . . . . . . 13 5.3.2. Home Address auto-configuration by the Mobile Node . . 11
5.3.1. Home Address assignment by the Home Agent . . . . . . 13 5.4. Authorization and Authentication with MSA . . . . . . . . 13
5.3.2. Home Address auto-configuration by the Mobile Node . . 14 6. Home Address registration in the DNS . . . . . . . . . . . . . 14
5.4. Authorization and Authentication with MSA . . . . . . . . 16 7. Summary of Bootstrapping Protocol Flow . . . . . . . . . . . . 16
6. Home Address registration in the DNS . . . . . . . . . . . . . 16 8. Option and Attribute Format . . . . . . . . . . . . . . . . . 17
7. Summary of Bootstrapping Protocol Flow . . . . . . . . . . . . 18 8.1. DNS Update mobility option . . . . . . . . . . . . . . . . 17
8. Option and Attribute Format . . . . . . . . . . . . . . . . . 19 8.2. MIP6_HOME_PREFIX attribute . . . . . . . . . . . . . . . . 18
8.1. DNS Update mobility option . . . . . . . . . . . . . . . . 19 9. Security Considerations . . . . . . . . . . . . . . . . . . . 19
8.2. MIP6_HOME_PREFIX attribute . . . . . . . . . . . . . . . . 21 9.1. HA Address Discovery . . . . . . . . . . . . . . . . . . . 19
9. Security Considerations . . . . . . . . . . . . . . . . . . . 22 9.2. Home Address Assignment through IKEv2 . . . . . . . . . . 21
9.1. HA Address Discovery . . . . . . . . . . . . . . . . . . . 22 9.3. SA Establishment Using EAP Through IKEv2 . . . . . . . . . 22
9.2. Home Address Assignment through IKEv2 . . . . . . . . . . 24 9.4. Back End Security Between the HA and AAA Server . . . . . 22
9.3. SA Establishment Using EAP Through IKEv2 . . . . . . . . . 24 9.5. Dynamic DNS Update . . . . . . . . . . . . . . . . . . . . 22
9.4. Back End Security Between the HA and AAA Server . . . . . 24 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
9.5. Dynamic DNS Update . . . . . . . . . . . . . . . . . . . . 25 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 23
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 24
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 26 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 24
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 27 13.1. Normative References . . . . . . . . . . . . . . . . . . . 24
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 13.2. Informative References . . . . . . . . . . . . . . . . . . 25
13.1. Normative References . . . . . . . . . . . . . . . . . . . 27 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 26
13.2. Informative References . . . . . . . . . . . . . . . . . . 27 Intellectual Property and Copyright Statements . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29
Intellectual Property and Copyright Statements . . . . . . . . . . 30
1. Introduction 1. Introduction
Mobile IPv6 [1] requires the Mobile Node to know its Home Agent Mobile IPv6 [1] requires the Mobile Node to know its Home Agent
Address, its own Home Address and the cryptographic materials (e.g. Address, its own Home Address and the cryptographic materials (e.g.
shared keys or certificates) needed to set up IPsec security shared keys or certificates) needed to set up IPsec security
associations with the Home Agent in order to protect Mobile IPv6 associations with the Home Agent in order to protect Mobile IPv6
signaling. This is generally referred to as the Mobile IPv6 signaling. This is generally referred to as the Mobile IPv6
bootstrapping problem [8]. bootstrapping problem [6].
Mobile IPv6 base protocol does not specify any method to Mobile IPv6 base protocol does not specify any method to
automatically acquire this information, which means that network automatically acquire this information, which means that network
administrators are normally required to manually set configuration administrators are normally required to manually set configuration
data on Mobile Nodes and HAs. However, in real deployments, manual data on Mobile Nodes and HAs. However, in real deployments, manual
configuration does not scale as the Mobile Nodes increase in number. configuration does not scale as the Mobile Nodes increase in number.
As discussed in [8], several bootstrapping scenarios can be As discussed in [6], several bootstrapping scenarios can be
identified depending on the relationship between the network operator identified depending on the relationship between the network operator
that authenticates a mobile node for granting network access service that authenticates a mobile node for granting network access service
(Access Service Authorizer, ASA) and the service provider that (Access Service Authorizer, ASA) and the service provider that
authorizes Mobile IPv6 service (Mobility Service Authorizer, MSA). authorizes Mobile IPv6 service (Mobility Service Authorizer, MSA).
This document describes a solution to the bootstrapping problem that This document describes a solution to the bootstrapping problem that
is applicable in a scenario where the MSA and the ASA are different is applicable in a scenario where the MSA and the ASA are different
entities (i.e. split scenario). entities (i.e. split scenario).
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [2]. document are to be interpreted as described in RFC 2119 [2].
General mobility terminology can be found in [9]. The following General mobility terminology can be found in [7]. The following
additional terms are used here: additional terms are used here:
Access Service Authorizer (ASA) Access Service Authorizer (ASA)
A network operator that authenticates a mobile node and A network operator that authenticates a mobile node and
establishes the mobile node's authorization to receive Internet establishes the mobile node's authorization to receive Internet
service. service.
Access Service Provider (ASP) Access Service Provider (ASP)
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prove authorization to obtain the service. prove authorization to obtain the service.
Split scenario Split scenario
A scenario where mobility service and network access service are A scenario where mobility service and network access service are
authorized by different entities. This implies that MSA is authorized by different entities. This implies that MSA is
different from ASA. different from ASA.
3. Split scenario 3. Split scenario
In the problem statement description [8] there is a clear assumption In the problem statement description [6] there is a clear assumption
that mobility service and network access service can be separate. that mobility service and network access service can be separate.
This assumption implies that mobility service and network access This assumption implies that mobility service and network access
service may be authorized by different entities. As an example, the service may be authorized by different entities. As an example, the
service model defined in [8] allows an enterprise network to deploy a service model defined in [6] allows an enterprise network to deploy a
Home Agent and offer Mobile IPv6 service to a user, even if the user Home Agent and offer Mobile IPv6 service to a user, even if the user
is accessing the Internet independent of its enterprise account is accessing the Internet independent of its enterprise account
(e.g., by using his personal WiFi hotspot account at a coffee shop). (e.g., by using his personal WiFi hotspot account at a coffee shop).
Therefore, in this document it is assumed that network access and Therefore, in this document it is assumed that network access and
mobility service are authorized by different entities, which means mobility service are authorized by different entities, which means
that authentication and authorization for mobility service and that authentication and authorization for mobility service and
network access will be considered separately. This scenario is network access will be considered separately. This scenario is
called split scenario. called split scenario.
Moreover, the model defined in [8] separates the entity providing the Moreover, the model defined in [6] separates the entity providing the
service from the entity that authenticates and authorizes the user. service from the entity that authenticates and authorizes the user.
This is similar to the roaming model for network access. Therefore, This is similar to the roaming model for network access. Therefore,
in the split scenario, two different cases can be identified in the split scenario, two different cases can be identified
depending on the relationship between the entity that provides the depending on the relationship between the entity that provides the
mobility service (i.e. Mobility Service Provider, MSP) and the mobility service (i.e. Mobility Service Provider, MSP) and the
entity that authenticates and authorizes the user (i.e. Mobility entity that authenticates and authorizes the user (i.e. Mobility
Service Authorizer, MSA). Service Authorizer, MSA).
Figure 1 depicts the split scenario when the MSP and the MSA are the Figure 1 depicts the split scenario when the MSP and the MSA are the
same entity. This means that the network operator that provides the same entity. This means that the network operator that provides the
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|MN| |MN|
+--+ +--+
Figure 2 -- Split Scenario (MSA != MSP) Figure 2 -- Split Scenario (MSA != MSP)
Note that Figure 1 and Figure 2 assume the use of an AAA protocol to Note that Figure 1 and Figure 2 assume the use of an AAA protocol to
authenticate and authorize the Mobile Node for mobility service. authenticate and authorize the Mobile Node for mobility service.
However, since IKEv2 allows EAP client authentication only and the However, since IKEv2 allows EAP client authentication only and the
server authentication needs to be performed based on certificates or server authentication needs to be performed based on certificates or
public keys, the Mobile Node potentially requires a certificate public keys, the Mobile Node potentially requires a certificate
revocation list check (CTL check) even though an AAA potocol is used revocation list check (CRL check) even though an AAA protocol is used
to authenticate and authorize the Mobile Node for mobility service. to authenticate and authorize the Mobile Node for mobility service.
If, instead, a PKI is used, the Mobile Node and HA exchange If, instead, PKI is used, the Mobile Node and HA use certificates to
certificates and there is no AAA server involved [10]. This is authenticate each other and there is no AAA server involved [8].
conceptually similar to Figure 1, since the MSP == MSA, except the This is conceptually similar to Figure 1, since the MSP == MSA,
Home Agent, and potentially the Mobile Node, may require a except the Home Agent, and potentially the Mobile Node, may require a
certificate revocation list check (CRL check) with the Certificate certificate revocation list check (CRL check) with the Certificate
Authority (CA). The CA may be either internal or external to the Authority (CA). The CA may be either internal or external to the
MSP. Figure 3 illustrates this. MSP. Figure 3 illustrates this.
Certificate Certificate
Authority Authority
+-------------+ +-------------+
| CA | | CA |
| server | | server |
+-------------+ +-------------+
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+--+ +--+
Figure 3 -- Split Scenario with PKI Figure 3 -- Split Scenario with PKI
The split scenario is the simplest model that can be identified, The split scenario is the simplest model that can be identified,
since no assumptions about the access network are made. This implies since no assumptions about the access network are made. This implies
that the mobility service is bootstrapped independently from the that the mobility service is bootstrapped independently from the
authentication protocol for network access used (e.g. EAP or even authentication protocol for network access used (e.g. EAP or even
open access). For this reason, the solution described in this open access). For this reason, the solution described in this
document and developed for this scenario could also be applied to the document and developed for this scenario could also be applied to the
integrated access network deployment model [8], even if it might not integrated access network deployment model [6], even if it might not
be optimized. be optimized.
4. Components of the solution 4. Components of the solution
The bootstrapping problem is composed of different sub-problems that The bootstrapping problem is composed of different sub-problems that
can be solved independently in a modular way. The components can be solved independently in a modular way. The components
identified and a brief overview of their solution follow. identified and a brief overview of their solution follow.
HA address discovery HA address discovery
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authentication can be performed both using certificates and using authentication can be performed both using certificates and using
EAP, depending on the network operator's deployment model. EAP, depending on the network operator's deployment model.
Home Address (HoA) assignment Home Address (HoA) assignment
The Mobile Node needs to know its Home Address in order to The Mobile Node needs to know its Home Address in order to
bootstrap Mobile IPv6 operation. The Home Address is assigned by bootstrap Mobile IPv6 operation. The Home Address is assigned by
the Home Agent during the IKEv2 exchange (as described in [4]). the Home Agent during the IKEv2 exchange (as described in [4]).
The solution defined in this document also allows the Mobile Node The solution defined in this document also allows the Mobile Node
to auto-configure its Home Address based on stateless auto- to auto-configure its Home Address based on stateless auto-
configuration [11], Cryptographically Generated Addresses [12] or configuration [9], Cryptographically Generated Addresses [10] or
privacy addresses [13]. privacy addresses [11].
Authentication and Authorization with MSA Authentication and Authorization with MSA
The user must be authenticated in order for the MSP to grant the The user must be authenticated in order for the MSP to grant the
service. Since the user credentials can be verified only by the service. Since the user credentials can be verified only by the
MSA, this authorization step is performed by the MSA. Moreover, MSA, this authorization step is performed by the MSA. Moreover,
the mobility service must be explicitly authorized by the MSA the mobility service must be explicitly authorized by the MSA
based on the user's profile. These operations are performed in based on the user's profile. These operations are performed in
different ways depending on the credentials used by the Mobile different ways depending on the credentials used by the Mobile
Node during the IKEv2 peer authentication and on the backend Node during the IKEv2 peer authentication and on the backend
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This section describes in detail the procedures needed to perform This section describes in detail the procedures needed to perform
Mobile IPv6 bootstrapping based on the components identified in the Mobile IPv6 bootstrapping based on the components identified in the
previous section. previous section.
5.1. Home Agent Address Discovery 5.1. Home Agent Address Discovery
Once a Mobile Node has obtained network access, it can perform Mobile Once a Mobile Node has obtained network access, it can perform Mobile
IPv6 bootstrapping. For this purpose, the Mobile Node queries the IPv6 bootstrapping. For this purpose, the Mobile Node queries the
DNS server to request information on Home Agent service. As DNS server to request information on Home Agent service. As
mentioned before in the document, the only information that needs to mentioned before in the document, the Mobile Node should be pre-
be pre-configured on the Mobile Node is the domain name of the configured with the domain name of the Mobility Service Provider.
Mobility Service Provider.
The Mobile Node needs to obtain the IP address of the DNS server The Mobile Node needs to obtain the IP address of a DNS server before
before it can send a DNS request. This can be pre-configured on the it can send a DNS request. This can be configured on the Mobile Node
Mobile Node or obtained through DHCPv6 from the visited link [14]. or obtained through DHCPv6 from the visited link [12]. In any case,
In any case, it is assumed that there is some kind of mechanism by it is assumed that there is some kind of mechanism by which the
which the Mobile Node is configured with a DNS server since a DNS Mobile Node is configured with a DNS server since a DNS server is
server is needed for many other reasons. needed for many other reasons.
Two options for DNS lookup for a Home Agent address are identified in Two options for DNS lookup for a Home Agent address are identified in
this document: DNS lookup by Home Agent Name and DNS lookup by this document: DNS lookup by Home Agent Name and DNS lookup by
service name. service name.
This document does not provide a specific mechanism to load balance This document does not provide a specific mechanism to load balance
different Mobile Nodes among Home Agents. It is possible for an MSP different Mobile Nodes among Home Agents. It is possible for an MSP
to achieve coarse-grained load balancing by dynamically updating the to achieve coarse-grained load balancing by dynamically updating the
SRV RR priorities to reflect the current load on the MSP's collection SRV RR priorities to reflect the current load on the MSP's collection
of Home Agents. Mobile Nodes then use the priority mechanism to of Home Agents. Mobile Nodes then use the priority mechanism to
preferentially select the least loaded HA. The effectiveness of this preferentially select the least loaded HA. The effectiveness of this
technique depends on how much of a load it will place on the DNS technique depends on how much of a load it will place on the DNS
servers, particularly if dynamic DNS is used for frequent updates. servers, particularly if dynamic DNS is used for frequent updates.
While this document specifies a Home Agent Address Discovery solution While this document specifies a Home Agent Address Discovery solution
based on DNS, when the ASP and the MSP are the same entity DHCP may based on DNS, when the ASP and the MSP are the same entity DHCP may
be used. See [15] for details. be used. See [13] for details.
5.1.1. DNS lookup by Home Agent Name 5.1.1. DNS lookup by Home Agent Name
In this case, the Mobile Node is configured with the Fully Qualified In this case, the Mobile Node is configured with the Fully Qualified
Domain Name of the Home Agent. As an example, the Mobile Node could Domain Name of the Home Agent. As an example, the Mobile Node could
be configured with the name "ha1.example.com", where "example.com" is be configured with the name "ha1.example.com", where "example.com" is
the domain name of the MSP granting the mobility service. the domain name of the MSP granting the mobility service.
The Mobile Node constructs a DNS request, by setting the QNAME to the The Mobile Node constructs a DNS request, by setting the QNAME to the
name of the Home Agent. The request has QTYPE set to 'AAAA', so that name of the Home Agent. The request has QTYPE set to 'AAAA', so that
the DNS server sends the IPv6 address of the Home Agent. Once the the DNS server sends the IPv6 address of the Home Agent. Once the
DNS server replies to this query, the Mobile Node knows its Home DNS server replies to this query, the Mobile Node knows its Home
Agent address and can run IKEv2 in order to set up the IPsec SAs and Agent address and can run IKEv2 in order to set up the IPsec SAs and
get a Home Address. get a Home Address.
Note that the configuration of a fixed home agent FQDN does allow Note that the configuration of a home agent FQDN on the mobile node
dynamic assignment of a localized home agent. Such dynamic can also be extended to dynamically assign a local home agent from
assignment would be useful, however, for instance from the point of the visited network. Such dynamic assignment would be useful, for
view of improving routing efficiency in bidirectional tunneling mode. instance, from the point of view of improving routing efficiency in
Enhancements or conventions for dynamic assignment are possible, but bidirectional tunneling mode. Enhancements or conventions for
are outside the scope of this specification. dynamic assignment of local home agents are outside the scope of this
specification.
5.1.2. DNS lookup by service name 5.1.2. DNS lookup by service name
RFC 2782 [3] defines the service resource record (SRV RR) that allows RFC 2782 [3] defines the service resource record (SRV RR) that allows
an operator to use several servers for a single domain, to move an operator to use several servers for a single domain, to move
services from host to host, and to designate some hosts as primary services from host to host, and to designate some hosts as primary
servers for a service and others as backups. Clients ask for a servers for a service and others as backups. Clients ask for a
specific service/protocol for a specific domain and get back the specific service/protocol for a specific domain and get back the
names of any available servers. names of any available servers.
RFC 2782 [3] also describes the policies to choose a service agent RFC 2782 [3] also describes the policies to choose a service agent
based on the preference and weight values. The DNS SRV record may based on the preference and weight values. The DNS SRV record may
contain the preference and weight values for multiple Home Agents contain the preference and weight values for multiple Home Agents
available to the Mobile Node in addition to the Home Agent FQDNs. If available to the Mobile Node in addition to the Home Agent FQDNs. If
multiple Home Agents are available in the DNS SRV record then Mobile multiple Home Agents are available in the DNS SRV record then Mobile
Node is responsible for processing the information as per policy and Node is responsible for processing the information as per policy and
for picking one Home Agent. If the Home Agent of choice does not for picking one Home Agent. If the Home Agent of choice does not
respond for some reason or the IKEv2 authentication fails, the Mobile respond to the IKE_SA_INIT messages or if IKEv2 authentication fails,
Node SHOULD try other Home Agents on the list. the Mobile Node SHOULD try the next Home Agent on the list. If none
of the Home Agents respond, the Mobile Node SHOULD try again after a
period of time that is configurable on the Mobile Node. If IKEv2
authentication fails with all Home Agents, it is an unrecoverable
error on the Mobile Node.
The service name for Mobile IPv6 Home Agent service as required by The service name for Mobile IPv6 Home Agent service as required by
RFC 2782 is "mip6" and the protocol name is "ipv6". Note that a RFC 2782 is "mip6" and the protocol name is "ipv6". Note that a
transport name cannot be used here because Mobile IPv6 does not run transport name cannot be used here because Mobile IPv6 does not run
over a transport protocol. over a transport protocol.
The SRV RR has a DNS type code of 33. As an example, the Mobile The SRV RR has a DNS type code of 33. As an example, the Mobile
constructs a request with QNAME set to "_mip6._ipv6.example.com" and constructs a request with QNAME set to "_mip6._ipv6.example.com" and
QTYPE to SRV. The reply contains the FQDNs of one or more servers, QTYPE to SRV. The reply contains the FQDNs of one or more servers,
that can then be resolved in a separate DNS transaction to the IP that can then be resolved in a separate DNS transaction to the IP
addresses. However, if there is room in the SRV reply, it is addresses. However, if there is room in the SRV reply, it is
RECOMMENDED that the DNS server also return the IP addresses of the RECOMMENDED that the DNS server also return the IP addresses of the
Home Agents in AAAA records as part of the additional data section Home Agents in AAAA records as part of the additional data section
(in order to avoid requiring an additional DNS round trip to resolve (in order to avoid requiring an additional DNS round trip to resolve
the FQDNs). the FQDNs).
5.1.3. Anycast Address for Home Agent Assignment
A FQDN MAY be bound to an IPv6 anycast address rather than to a
unicast address for a Home Agent. Since anycast addresses are
indistinguishable from unicast addresses, there is no distinction in
the AAAA record between a unicast address and an anycast address.
The anycast address allows the home network to assign a Home Agent to
a Mobile Node on a case by case basis at the time that the Mobile
Node bootstraps, rather than having the Mobile Node select the Home
Agent address. Section 5.2.1 below describes how the IKEv2
transaction is modified by anycast Home Agent assignment. A FQDN
bound to an anycast address MAY be returned by a SRV RR query.
Mobile Nodes that implement this specification MUST be prepared to
handle an anycast address for Home Agent assignment.
The anycast address reserved by RFC 2526 [5] for Home Agents on the
same link MAY be used for bootstrapping. Other deployment-specific
anycast addresses, spanning a wider topology, MAY also be used.
Note that anycast forwarding as specified in RFC 4291 [6] allows the
node which has the anycast address assigned to one of its network
interfaces to make the decision about to which address forwarding
should occur based only on routing metric information. Use of any
other criteria, such as load balancing or service profile offered by
the Home Agent, in a standardized way is currently unsupported.
Assignment based on other criteria than routing metrics can be
achieved by having the home agent receiving the forwarded message
perform the home agent selection based on other critera, but the
mechanism for this is out of scope of this draft.
5.2. IPsec Security Associations setup 5.2. IPsec Security Associations setup
As soon as the Mobile Node has discovered the Home Agent Address, it As soon as the Mobile Node has discovered the Home Agent Address, it
establishes an IPsec Security Association with the Home Agent itself establishes an IPsec Security Association with the Home Agent itself
through IKEv2. The detailed description of this procedure is through IKEv2. The detailed description of this procedure is
provided in [4]. If the Mobile Node wants the HA to register the provided in [4]. If the Mobile Node wants the HA to register the
Home Address in the DNS, it MUST use the FQDN as the initiator Home Address in the DNS, it MUST use the FQDN as the initiator
identity in IKE_AUTH step of the IKEv2 exchange (IDi). This is identity in IKE_AUTH step of the IKEv2 exchange (IDi). This is
needed because the Mobile Node has to provide it is the owner of the needed because the Mobile Node has to prove it is the owner of the
FQDN provided in the subsequent DNS Update Option. See section 6 and FQDN provided in the subsequent DNS Update Option. See section 6 and
section 9 for a more detailed analysis on this issue. section 9 for a more detailed analysis on this issue.
The IKEv2 Mobile Node to Home Agent authentication can be performed The IKEv2 Mobile Node to Home Agent authentication can be performed
using either IKEv2 public key signatures or the Extensible using either IKEv2 public key signatures or the Extensible
Authentication Protocol (EAP). The details about how to use IKEv2 Authentication Protocol (EAP). The details about how to use IKEv2
authentication are described in [4] and [7]. Choice of an IKEv2 peer authentication are described in [4] and [5]. Choice of an IKEv2 peer
authentication method depends on the deployment. However, IKEv2 authentication method depends on the deployment. The Mobile Node
restricts the Home Agent to Mobile Node authentication to use public should be configured with the information on which IKEv2
key signature-based authentication. authentication method to use. However, IKEv2 restricts the Home
Agent to Mobile Node authentication to use public key signature-based
5.2.1. IKEv2 Transaction with anycast Home Agent assignment authentication.
If an anycast address is returned in response to DNS resolution of an
FQDN, the IKEv2 transaction between the Mobile Node and Home Agent is
modified. The Mobile Node sends the IKE_SA_INIT request to the
anycast address. The node which has the anycast address assigned to
one of its network interfaces selects a Home Agent address from the
set of Home Agents managed by the node, and forwards the IKE_SA_INIT.
If the set of Home Agents is empty, the node simply drops the packet.
The Home Agent answers using its own address, and includes an "under
attack" cookie, in accordance with RFC 4306 [7]. The Mobile Node
notes the Home Agent address and resends the IKE_SA_INIT message to
the Home Agent, along with the cookie.
The resulting IKE_SA_INIT transaction is the following:
Initiator Responder ("best" HA)
--------- ---------------------
(IP_I:500 -> ANYCAST:500)
HDR(A,0), SAi1, KEi, Ni -->
(IP_R:500 -> IP_I:500)
<-- HDR(A,0), N(COOKIE)
(IP_I:500 -> IP_R:500)
HDR(A,0), N(COOKIE), SAi1, KEi, Ni -->
(IP_R:500 -> IP_I:500)
<-- HDR(A,B), SAr1, KEr, Nr,[CERTREQ]
(IP_I:500 -> IP_R:500)
HDR(A,B), SK {IDi, [CERT,] [CERTREQ,]
[IDr,]AUTH, SAi2, TSi, TSr} -->
(IP_R:500 -> IP_I:500)
<-- HDR(A,B), SK {IDr, [CERT,] AUTH,
SAr2, TSi, TSr}
Note that the "under attack" cookie is being used to force a new
IKE_SA_INIT exchange with the home agent, after the initial
IKE_SA_INIT request/response exchange is used to identify the home
agent that will be serving the mobile node.
When the mobile node sends an IKE_SA_INIT request message to an
anycast address, the response comes back from an unicast address.
RFC 4306 requires that the responder MUST use the destination address
on the request message as the source address on the response message.
However, it is assumed that RFC 4306 is talking about unicast
addresses in that context. The mobile node implementation compliant
to this specification must relax the requirement from RFC 4306 and be
willing to process the response from an unicast address when it sends
a request to an anycast address.
The use of anycast address as specified above requires the
implementation of anycast forwarding in such a way that the Home
Agent can distinguish between an IKE_SA_INIT forwarded through an
anycast address and one sent directly from the Mobile Node. One
possible mechanism is to use IP-in-ip tunneling for forwarding the
IKE_SA_INIT. In this case, the Home Agent can identify a forwarded
IKE_SA_INIT based on the incoming interface or based on the
additional IP header. Other mechanisms may be used.
Home Agents SHOULD NOT include an "under attack" cookie unless the
IKE_SA_INIT was forwarded through an anycast address or the Home
Agent believes that it is, in fact, under attack, in order to
maintain conformance with RFC 4306 for other applications.
A mobile node's security associations with its home agent may expire
while it still has a valid binding cache entry at the the home agent.
In this case, the mobile node MUST NOT use an anycast address as the
destination address in the IKE_SA_INIT exchange to setup new security
associations. It MUST try to setup security associations with its
existing home agent.
5.3. Home Address assignment 5.3. Home Address assignment
Home Address assignment is performed during the IKEv2 exchange. The Home Address assignment is performed during the IKEv2 exchange. The
Home Address can be assigned directly by the Home Agent or can be Home Address can be assigned directly by the Home Agent or can be
auto-configured by the Mobile Node. auto-configured by the Mobile Node.
5.3.1. Home Address assignment by the Home Agent 5.3.1. Home Address assignment by the Home Agent
When the Mobile Node runs IKEv2 with its Home Agent, it can request a When the Mobile Node runs IKEv2 with its Home Agent, it can request a
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including an INTERNAL_IP6_ADDRESS attribute. When the Home Agent including an INTERNAL_IP6_ADDRESS attribute. When the Home Agent
processes the message, it allocates a HoA and sends it a CFG_REPLY processes the message, it allocates a HoA and sends it a CFG_REPLY
message. The Home Agent could consult a DHCP server on the home link message. The Home Agent could consult a DHCP server on the home link
for the actual home address allocation. This is explained in detail for the actual home address allocation. This is explained in detail
in [4]. in [4].
5.3.2. Home Address auto-configuration by the Mobile Node 5.3.2. Home Address auto-configuration by the Mobile Node
With the type of assignment described in the previous section, the With the type of assignment described in the previous section, the
Home Address cannot be generated based on Cryptographically Generated Home Address cannot be generated based on Cryptographically Generated
Addresses (CGAs) [12] or based on the privacy extensions for Addresses (CGAs) [10] or based on the privacy extensions for
stateless auto-configuration [13]. However, the Mobile Node might stateless auto-configuration [11]. However, the Mobile Node might
want to have an auto-configured HoA based on these mechanisms. It is want to have an auto-configured HoA based on these mechanisms. It is
worthwhile to mention that the auto-configuration procedure described worthwhile to mention that the auto-configuration procedure described
in this section cannot be used in some possible deployments, since in this section cannot be used in some possible deployments, since
the Home Agents might be provisioned with pools of allowed Home the Home Agents might be provisioned with pools of allowed Home
Addresses. Addresses.
In the simplest case, the Mobile Node is provided with a pre- In the simplest case, the Mobile Node is provided with a pre-
configured home prefix and home prefix length. In this case the configured home prefix and home prefix length. In this case the
Mobile Node creates a Home Address based on the pre-configured prefix Mobile Node creates a Home Address based on the pre-configured prefix
and sends it to the Home Agent including an INTERNAL_IP6_ADDRESS and sends it to the Home Agent including an INTERNAL_IP6_ADDRESS
attribute in a Configuration Payload of type CFG_REQUEST. If the attribute in a Configuration Payload of type CFG_REQUEST. If the
Home Address is valid, the Home Agent replies with a CFG_REPLY, Home Address is valid, the Home Agent replies with a CFG_REPLY,
including an INTERNAL_IP6_ADDRESS with the same address. If the Home including an INTERNAL_IP6_ADDRESS with the same address. If the Home
Address provided by the Mobile Node is not valid, the Home Agent Address provided by the Mobile Node is not valid, the Home Agent
assigns a different Home Address including an INTERNAL_IP6_ADDRESS assigns a different Home Address including an INTERNAL_IP6_ADDRESS
attribute with a new value. According to [7] the Mobile Node MUST attribute with a new value. According to [5] the Mobile Node MUST
use the address sent by the Home Agent. Later, if the Mobile Node use the address sent by the Home Agent. Later, if the Mobile Node
wants to use an auto-configured Home Address (e.g. based on CGA), it wants to use an auto-configured Home Address (e.g. based on CGA), it
can run Mobile Prefix Discovery, obtain a prefix, auto-configure a can run Mobile Prefix Discovery, obtain a prefix, auto-configure a
new Home Address and then perform a new CREATE_CHILD_SA exchange. new Home Address and then perform a new CREATE_CHILD_SA exchange.
If the Mobile Node is not provided with a pre-configured Home Prefix, If the Mobile Node is not provided with a pre-configured Home Prefix,
the Mobile cannot simply propose an auto-configured HoA in the the Mobile cannot simply propose an auto-configured HoA in the
Configuration Payload since the Mobile Node does not know the home Configuration Payload since the Mobile Node does not know the home
prefix before the start of the IKEv2 exchange. The Mobile Node must prefix before the start of the IKEv2 exchange. The Mobile Node must
obtain the home prefix and the home prefix length before it can obtain the home prefix and the home prefix length before it can
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prefix length on the home link is 64 bits and send its interface prefix length on the home link is 64 bits and send its interface
identifier to the Home Agent in the INTERNAL_IP6_ADDRESS attribute identifier to the Home Agent in the INTERNAL_IP6_ADDRESS attribute
within the CFG_REQ payload. Even though this approach does not tie within the CFG_REQ payload. Even though this approach does not tie
the prefix on the home link and the Home Agent's address, it still the prefix on the home link and the Home Agent's address, it still
requires that the home prefix length is 64 bits. requires that the home prefix length is 64 bits.
For this reason the Mobile Node needs to obtain the home link For this reason the Mobile Node needs to obtain the home link
prefixes through the IKEv2 exchange. In the Configuration Payload prefixes through the IKEv2 exchange. In the Configuration Payload
during the IKE_AUTH exchange, the Mobile Node includes the during the IKE_AUTH exchange, the Mobile Node includes the
MIP6_HOME_PREFIX attribute in the CFG_REQUEST message. The Home MIP6_HOME_PREFIX attribute in the CFG_REQUEST message. The Home
Agent, when it processes this message, should include in the Agent, when it processes this message, MUST include in the CFG_REPLY
CFG_REPLY payload prefix information for one prefix on the home link. payload prefix information for one prefix on the home link. This
This prefix information includes the prefix length (see Section 8.2). prefix information includes the prefix length (see Section 8.2). The
The Mobile Node auto-configures a Home Address from the prefix Mobile Node auto-configures a Home Address from the prefix returned
returned in the CFG_REPLY message and runs a CREATE_CHILD_SA exchange in the CFG_REPLY message and runs a CREATE_CHILD_SA exchange to
to create security associations for the new Home Address. create security associations for the new Home Address.
As mentioned before in this document, there are deployments where As mentioned before in this document, there are deployments where
auto-configuration of the Home Address cannot be used. In this case, auto-configuration of the Home Address cannot be used. In this case,
when the Home Agent receives a CFG_REQUEST including a when the Home Agent receives a CFG_REQUEST including a
MIP6_HOME_PREFIX attribute, in the subsequent IKE response it MIP6_HOME_PREFIX attribute, in the subsequent IKE response it
includes a Notify Payload type "USE_ASSIGNED_HoA" and the related includes a Notify Payload type "USE_ASSIGNED_HoA" and the related
Home Address in a INTERNAL_IP6_ADDRESS attribute. If the Mobile Node Home Address in a INTERNAL_IP6_ADDRESS attribute. If the Mobile Node
gets a "USE_ASSIGNED_HoA" Notify Payload in response to the gets a "USE_ASSIGNED_HoA" Notify Payload in response to the
Configuration Payload containing the MIP6_HOME_PREFIX attribute, it Configuration Payload containing the MIP6_HOME_PREFIX attribute, it
looks for an INTERNAL_IP6_ADDRESS attribute and MUST use the address looks for an INTERNAL_IP6_ADDRESS attribute and MUST use the address
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Mobile Node is going to expire. Mobile Node is going to expire.
Due to all these reasons, the Home Agent may need to contact the MSA Due to all these reasons, the Home Agent may need to contact the MSA
in order to authenticate the Mobile Node and authorize mobility in order to authenticate the Mobile Node and authorize mobility
service. This can be accomplished based on a Public Key service. This can be accomplished based on a Public Key
Infrastructure if certificates are used and a PKI is deployed by the Infrastructure if certificates are used and a PKI is deployed by the
MSP and MSA. On the other hand, if the Mobile Node is provided with MSP and MSA. On the other hand, if the Mobile Node is provided with
other types of credentials, the AAA infrastructure must be used. other types of credentials, the AAA infrastructure must be used.
The definition of this backend communication is out of the scope of The definition of this backend communication is out of the scope of
this document. In [16] a list of goals for such a communication is this document. In [14] a list of goals for such a communication is
provided. provided. [15] and [16] define the RADIUS and Diameter extensions,
respectively, for the backend communication.
6. Home Address registration in the DNS 6. Home Address registration in the DNS
In order that the Mobile Node is reachable through its dynamically In order that the Mobile Node is reachable through its dynamically
assigned Home Address, the DNS needs to be updated with the new Home assigned Home Address, the DNS needs to be updated with the new Home
Address. Since applications make use of DNS lookups on FQDN to find Address. Since applications make use of DNS lookups on FQDN to find
a node, the DNS update is essential for providing IP reachability to a node, the DNS update is essential for providing IP reachability to
the Mobile Node, which is the main purpose of the Mobile IPv6 the Mobile Node, which is the main purpose of the Mobile IPv6
protocol. The need for DNS updating is not discussed in RFC 3775 protocol. The need for DNS updating is not discussed in RFC 3775
since it assumes that the Mobile Node is provisioned with a static since it assumes that the Mobile Node is provisioned with a static
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server and the DNS entry update can be performed by the AAA server of server and the DNS entry update can be performed by the AAA server of
the MSA. In order to accomplish this, the Home Agent sends to the the MSA. In order to accomplish this, the Home Agent sends to the
AAA server the FQDN-HoA pair through the AAA protocol. This message AAA server the FQDN-HoA pair through the AAA protocol. This message
is proxied by the AAA infrastructure of the MSP and is received by is proxied by the AAA infrastructure of the MSP and is received by
the AAA server of the MSA. The AAA server of the MSA perform the DNS the AAA server of the MSA. The AAA server of the MSA perform the DNS
update based on [17]. Notice that, even in this case, the Home Agent update based on [17]. Notice that, even in this case, the Home Agent
is always required to perform a DNS update for the reverse entry, is always required to perform a DNS update for the reverse entry,
since this is always performed in the DNS server of the MSP. The since this is always performed in the DNS server of the MSP. The
detailed description of the communication between Home Agent and AAA detailed description of the communication between Home Agent and AAA
is out of the scope of this document. More details are provided in is out of the scope of this document. More details are provided in
[16]. [14].
A mechanism to remove stale DNS entries is needed. A DNS entry A mechanism to remove stale DNS entries is needed. A DNS entry
becomes stale when the related Home Address is no longer used by the becomes stale when the related Home Address is no longer used by the
Mobile Node. To remove a DNS entry, the Mobile Node includes in the Mobile Node. To remove a DNS entry, the Mobile Node includes in the
Binding Update the DNS Update mobility option, with the flag R set in Binding Update the DNS Update mobility option, with the flag R set in
the option. After receiving the Binding Update, the Home Agent MUST the option. After receiving the Binding Update, the Home Agent MUST
remove the DNS entry identified by the FQDN provided by the Mobile remove the DNS entry identified by the FQDN provided by the Mobile
Node and the Home Address included in the Home Address Option. The Node and the Home Address included in the Home Address Option. The
procedure for sending a dynamic DNS update message is specified in procedure for sending a dynamic DNS update message is specified in
[17]. As mentioned above, the dynamic DNS update SHOULD be performed [17]. As mentioned above, the dynamic DNS update SHOULD be performed
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1. A legitimate client obtains a bogus Home Agent address from a 1. A legitimate client obtains a bogus Home Agent address from a
bogus DNS server. This is sometimes called a "pharming" attack, bogus DNS server. This is sometimes called a "pharming" attack,
2. An attacking client obtains a legitimate Home Agent address from 2. An attacking client obtains a legitimate Home Agent address from
a legitimate server. a legitimate server.
The risk in Case 1 is mitigated because the Mobile Node is required The risk in Case 1 is mitigated because the Mobile Node is required
to conduct an IKE transaction with the Home Agent prior to performing to conduct an IKE transaction with the Home Agent prior to performing
a Binding Update to establish Mobile IPv6 service. According to the a Binding Update to establish Mobile IPv6 service. According to the
IKEv2 specification [7], the responder must present the initiator IKEv2 specification [5], the responder must present the initiator
with a valid certificate containing the responder's public key, and with a valid certificate containing the responder's public key, and
the responder to initiator IKE_AUTH message must be protected with an the responder to initiator IKE_AUTH message must be protected with an
authenticator calculated using the public key in the certificate. authenticator calculated using the public key in the certificate.
Thus, an attacker would have to set up both a bogus DNS server and a Thus, an attacker would have to set up both a bogus DNS server and a
bogus Home Agent, and provision the Home Agent with a certificate bogus Home Agent, and provision the Home Agent with a certificate
that a victim Mobile Node could verify. If the Mobile Node can that a victim Mobile Node could verify. If the Mobile Node can
detect that the certificate is not trustworthy, the attack will be detect that the certificate is not trustworthy, the attack will be
foiled when the Mobile Node attempts to set up the IKE SA. foiled when the Mobile Node attempts to set up the IKE SA.
The risk in Case 2 is limited for a single Mobile Node to Home Agent The risk in Case 2 is limited for a single Mobile Node to Home Agent
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traffic on the Home Agent networks to detect when traffic volume traffic on the Home Agent networks to detect when traffic volume
increases abnormally indicating a possible DoS attack, and hot spares increases abnormally indicating a possible DoS attack, and hot spares
that can quickly be switched on in the event an attack is mounted on that can quickly be switched on in the event an attack is mounted on
an operating collection of Home Agents. DoS attacks of moderate an operating collection of Home Agents. DoS attacks of moderate
intensity should be foiled during the IKEv2 transaction. IKEv2 intensity should be foiled during the IKEv2 transaction. IKEv2
implementations are expected to generate their cookies without any implementations are expected to generate their cookies without any
saved state, and to time out cookie generation parameters frequently, saved state, and to time out cookie generation parameters frequently,
with the timeout value increasing if a DoS attack is suspected. This with the timeout value increasing if a DoS attack is suspected. This
should prevent state depletion attacks, and should assure continued should prevent state depletion attacks, and should assure continued
service to legitimate clients until the practical limits on the service to legitimate clients until the practical limits on the
network bandwith and processing capacity of the Home Agent network network bandwidth and processing capacity of the Home Agent network
are reached. are reached.
Explicit security measures between the DNS server and host, such Explicit security measures between the DNS server and host, such
DNSSEC [18] or TSIG/TKEY [19] [20] can mitigate the risk of 1) and DNSSEC [18] or TSIG/TKEY [19] [20] can mitigate the risk of 1) and
2), but these security measures are not widely deployed on end nodes. 2), but these security measures are not widely deployed on end nodes.
These security measures are not sufficient to protect the Home Agent These security measures are not sufficient to protect the Home Agent
address against DoS attack, however, because a node having a address against DoS attack, however, because a node having a
legitimate security association with the DNS server could legitimate security association with the DNS server could
nevertheless intentionally or inadvertently cause the Home Agent nevertheless intentionally or inadvertently cause the Home Agent
address to become the target of DoS. address to become the target of DoS.
Finally notice that assignment of an home agent from the serving Finally notice that assignment of an home agent from the serving
network access provider's (local home agent) or a home agent from a network access provider's (local home agent) or a home agent from a
nearby network (nearby home agent) may set up the potential to nearby network (nearby home agent) may set up the potential to
compromise a mobile node's location privacy. However, since a compromise a mobile node's location privacy. A home address anchored
standardized mechanism of assigning local or nearby home agents is at such home agent contains some information about the topological
out of scope for this document, it is not possible to present location of the mobile node. Consequently, a mobile node requiring
detailed security considerations. Please see other drafts that location privacy should not disclose this home address to nodes that
contain detailed mechanisms for localized home agent assignment, such are not authorized to learn the mobile node's location, e.g., by
as [15], for information on the location privacy properties of updating DNS with the new home address.
particular home agent assignment mechanisms.
Security considerations for discovering HA using DHCP are covered in Security considerations for discovering HA using DHCP are covered in
[21]. [21].
9.2. Home Address Assignment through IKEv2 9.2. Home Address Assignment through IKEv2
Mobile IPv6 bootstrapping assigns the home address through the IKEv2 Mobile IPv6 bootstrapping assigns the home address through the IKEv2
transaction. The Mobile Node can either choose to request an transaction. The Mobile Node can either choose to request an
address, similar to DHCP, or the Mobile Node can request a prefix on address, similar to DHCP, or the Mobile Node can request a prefix on
the home link then auto-configure an address. the home link then auto-configure an address.
RFC 3775 [1] requires that a Home Agent check authorization of a home RFC 3775 [1] requires that a Home Agent check authorization of a home
address received during a Binding Update. Therefore, the home agent address received during a Binding Update. Therefore, the home agent
MUST authorize each home address allocation and use. This MUST authorize each home address allocation and use. This
authorization is based on linking the mobile node identity used in authorization is based on linking the mobile node identity used in
the IKEv2 authentication process and the home address. Home agents the IKEv2 authentication process and the home address. Home agents
MUST support at least the following two modes of authorization: MUST implement at least the following two modes of authorization:
o Configured home address(es) for each mobile node. In this mode, o Configured home address(es) for each mobile node. In this mode,
the home agent or infrastructure nodes behind it know what the home agent or infrastructure nodes behind it know what
addresses a specific mobile node is authorized to use. The mobile addresses a specific mobile node is authorized to use. The mobile
node is allowed to request these addresses, or if the mobile node node is allowed to request these addresses, or if the mobile node
requests any home address, these addresses are returned to it. requests any home address, these addresses are returned to it.
o First-come-first-served (FCFS). In this mode, the home agent o First-come-first-served (FCFS). In this mode, the home agent
maintains a pool of "used" addresses, and allows mobile nodes to maintains a pool of "used" addresses, and allows mobile nodes to
request any address, as long as it is not used by another mobile request any address, as long as it is not used by another mobile
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Security considerations for authentication of the IKE transaction Security considerations for authentication of the IKE transaction
using EAP are covered in [4] . using EAP are covered in [4] .
9.4. Back End Security Between the HA and AAA Server 9.4. Back End Security Between the HA and AAA Server
Some deployments of Mobile IPv6 bootstrapping may use an AAA server Some deployments of Mobile IPv6 bootstrapping may use an AAA server
to handle authorization for mobility service. This process has its to handle authorization for mobility service. This process has its
own security requirements, but the back end protocol for Home Agent own security requirements, but the back end protocol for Home Agent
to AAA server interface is not covered in this draft. Please see to AAA server interface is not covered in this draft. Please see
[16] for a discussion of this interface. [14] for a discussion of this interface.
9.5. Dynamic DNS Update 9.5. Dynamic DNS Update
If a Home Agent performs dynamic DNS update on behalf of the Mobile If a Home Agent performs dynamic DNS update on behalf of the Mobile
Node directly with the DNS server, the Home Agent MUST have a Node directly with the DNS server, the Home Agent MUST have a
security association of some type with the DNS server. The security security association of some type with the DNS server. The security
association MAY be established either using DNSSEC [18] or TSIG/TKEY association MAY be established either using DNSSEC [18] or TSIG/TKEY
[19][20]. A security association is required even if the DNS server [19][20]. A security association is REQUIRED even if the DNS server
is in the same administrative domain as the Home Agent. The security is in the same administrative domain as the Home Agent. The security
association SHOULD be separate from the security associations used association SHOULD be separate from the security associations used
for other purposes, such as AAA. for other purposes, such as AAA.
In the case where the Mobility Service Provider is different from the In the case where the Mobility Service Provider is different from the
Mobility Service Authorizer, the network administrators may want to Mobility Service Authorizer, the network administrators may want to
limit the number of cross-administrative domain security limit the number of cross-administrative domain security
associations. If the Mobile Node's FQDN is in the Mobility Service associations. If the Mobile Node's FQDN is in the Mobility Service
Authorizer's domain, since a security association for AAA signaling Authorizer's domain, since a security association for AAA signaling
involved in mobility service authorization is required in any case, involved in mobility service authorization is required in any case,
the Home Agent can send the Mobile Node's FQDN to the AAA server the Home Agent can send the Mobile Node's FQDN to the AAA server
under the HA-AAA server security association, and the AAA server can under the HA-AAA server security association, and the AAA server can
perform the update. In that case, a security association is required perform the update. In that case, a security association is required
between the AAA server and DNS server for the dynamic DNS update. between the AAA server and DNS server for the dynamic DNS update.
See [16] for a deeper discussion of the Home Agent to AAA server See [14] for a deeper discussion of the Home Agent to AAA server
interface. interface.
Regardless of whether the AAA server or Home Agent performs DNS Regardless of whether the AAA server or Home Agent performs DNS
update, the authorization of the Mobile Node to update a FQDN MUST be update, the authorization of the Mobile Node to update a FQDN MUST be
checked prior to the performance of the update. It is an checked prior to the performance of the update. It is an
implementation issue as to how authorization is determined. However, implementation issue as to how authorization is determined. However,
in order to allow this authorization step, the Mobile Node MUST use a in order to allow this authorization step, the Mobile Node MUST use a
FQDN as the IDi in IKE_AUTH step of the IKEv2 exchange. The FQDN FQDN as the IDi in IKE_AUTH step of the IKEv2 exchange. The FQDN
MUST be the same that will be provided by the Mobile Node in the DNS MUST be the same that will be provided by the Mobile Node in the DNS
Update Option. Update Option.
In case EAP over IKEv2 is used to set-up the IPsec SA, the Home Agent In case EAP over IKEv2 is used to set-up the IPsec SA, the Home Agent
gets authorization information about the Mobile Node's FQDN via the gets authorization information about the Mobile Node's FQDN via the
AAA back end communication performed during IKEv2 exchange. The AAA back end communication performed during IKEv2 exchange. The
outcome of this step will give the Home Agent the necessary outcome of this step will give the Home Agent the necessary
information to authorize the DNS update request of the Mobile Node. information to authorize the DNS update request of the Mobile Node.
See [16] for details about the communication between the AAA server See [14] for details about the communication between the AAA server
and the Home Agent needed to perform the authorization. and the Home Agent needed to perform the authorization.
In case certificates are used in IKEv2, the authorization information In case certificates are used in IKEv2, the authorization information
about the FQDN for DNS update MUST be present in the certificate about the FQDN for DNS update MUST be present in the certificate
provided by the Mobile Node. Since the IKEv2 specification does not provided by the Mobile Node. Since the IKEv2 specification does not
include a required certificate type, it is not possible to specify include a required certificate type, it is not possible to specify
precisely how the Moible Node's FQDN should appear in the precisely how the Mobile Node's FQDN should appear in the
certificate. However, as an example, if the certificate type is certificate. However, as an example, if the certificate type is
"X.509 Certificate - Signature" (one of the recommended types) then "X.509 Certificate - Signature" (one of the recommended types) then
the FQDN may appear in the subjectAltName attribute extension [22]. the FQDN may appear in the subjectAltName attribute extension [22].
10. IANA Considerations 10. IANA Considerations
This document defines a new Mobility Option and a new IKEv2 This document defines a new Mobility Option and a new IKEv2
Configuration Attribute Type. Configuration Attribute Type.
The following values should be assigned: The following values should be assigned:
o from "Mobility Option" namespace ([1]): DNS-UPDATE-TYPE o from "Mobility Option" namespace ([1]): DNS-UPDATE-TYPE
(Section 8.1) (Section 8.1)
o from "IKEv2 Configuration Payload Attribute Types" namespace o from "IKEv2 Configuration Payload Attribute Types" namespace
([7]): MIP6_HOME_PREFIX attribute (Section 8.2) ([5]): MIP6_HOME_PREFIX attribute (Section 8.2)
o from "IKEv2 Notify Payload Error Types" namespace ([7]): o from "IKEv2 Notify Payload Error Types" namespace ([5]):
USE_ASSIGNED_HoA error type (Section 5.3.2) USE_ASSIGNED_HoA error type (Section 5.3.2)
11. Contributors 11. Contributors
This contribution is a joint effort of the bootstrapping solution This contribution is a joint effort of the bootstrapping solution
design team of the MIP6 WG. The contributors include Basavaraj design team of the MIP6 WG. The contributors include Basavaraj
Patil, Alpesh Patel, Jari Arkko, James Kempf, Yoshihiro Ohba, Gopal Patil, Alpesh Patel, Jari Arkko, James Kempf, Yoshihiro Ohba, Gopal
Dommety, Alper Yegin, Junghoon Jee, Vijay Devarapalli, Kuntal Dommety, Alper Yegin, Junghoon Jee, Vijay Devarapalli, Kuntal
Chowdury, Julien Bournelle. Francis Dupont and Kilian Weniger have Chowdury, Julien Bournelle.
contributed on the anycast HA assignment procedure.
The design team members can be reached at: The design team members can be reached at:
Gerardo Giaretta gerardog@qualcomm.com Gerardo Giaretta gerardog@qualcomm.com
Basavaraj Patil basavaraj.patil@nokia.com Basavaraj Patil basavaraj.patil@nokia.com
Alpesh Patel alpesh@cisco.com Alpesh Patel alpesh@cisco.com
Jari Arkko jari.arkko@kolumbus.fi Jari Arkko jari.arkko@kolumbus.fi
skipping to change at page 27, line 36 skipping to change at page 25, line 6
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[3] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for [3] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782, specifying the location of services (DNS SRV)", RFC 2782,
February 2000. February 2000.
[4] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with [4] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with
IKEv2 and the Revised IPsec Architecture", RFC 4877, IKEv2 and the Revised IPsec Architecture", RFC 4877,
April 2007. April 2007.
[5] Johnson, D. and S. Deering, "Reserved IPv6 Subnet Anycast [5] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
Addresses", RFC 2526, March 1999.
[6] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[7] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
RFC 4306, December 2005. RFC 4306, December 2005.
13.2. Informative References 13.2. Informative References
[8] Patel, A. and G. Giaretta, "Problem Statement for bootstrapping [6] Patel, A. and G. Giaretta, "Problem Statement for bootstrapping
Mobile IPv6 (MIPv6)", RFC 4640, September 2006. Mobile IPv6 (MIPv6)", RFC 4640, September 2006.
[9] Manner, J. and M. Kojo, "Mobility Related Terminology", [7] Manner, J. and M. Kojo, "Mobility Related Terminology",
RFC 3753, June 2004. RFC 3753, June 2004.
[10] Adams, C., Farrell, S., Kause, T., and T. Mononen, "Internet [8] Adams, C., Farrell, S., Kause, T., and T. Mononen, "Internet
X.509 Public Key Infrastructure Certificate Management Protocol X.509 Public Key Infrastructure Certificate Management Protocol
(CMP)", RFC 4210, September 2005. (CMP)", RFC 4210, September 2005.
[11] Narten, T., "Neighbor Discovery for IP version 6 (IPv6)", [9] Narten, T., "Neighbor Discovery for IP version 6 (IPv6)",
draft-ietf-ipv6-2461bis-11 (work in progress), March 2007. draft-ietf-ipv6-2461bis-11 (work in progress), March 2007.
[12] Aura, T., "Cryptographically Generated Addresses (CGA)", [10] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, March 2005. RFC 3972, March 2005.
[13] Narten, T. and R. Draves, "Privacy Extensions for Stateless [11] Narten, T. and R. Draves, "Privacy Extensions for Stateless
Address Autoconfiguration in IPv6", RFC 3041, January 2001. Address Autoconfiguration in IPv6", RFC 3041, January 2001.
[14] Droms, R., "DNS Configuration options for Dynamic Host [12] Droms, R., "DNS Configuration options for Dynamic Host
Configuration Protocol for IPv6 (DHCPv6)", RFC 3646, Configuration Protocol for IPv6 (DHCPv6)", RFC 3646,
December 2003. December 2003.
[15] Chowdhury, K. and A. Yegin, "MIP6-bootstrapping for the [13] Chowdhury, K. and A. Yegin, "MIP6-bootstrapping for the
Integrated Scenario", Integrated Scenario",
draft-ietf-mip6-bootstrapping-integrated-dhc-02 (work in draft-ietf-mip6-bootstrapping-integrated-dhc-04 (work in
progress), February 2007. progress), June 2007.
[16] Giaretta, G., "AAA Goals for Mobile IPv6", [14] Giaretta, G., "AAA Goals for Mobile IPv6",
draft-ietf-mip6-aaa-ha-goals-03 (work in progress), draft-ietf-mip6-aaa-ha-goals-03 (work in progress),
September 2006. September 2006.
[15] Chowdhury, K., "RADIUS Mobile IPv6 Support",
draft-ietf-mip6-radius-02 (work in progress), March 2007.
[16] Bournelle, J., "Diameter Mobile IPv6: HA <-> HAAA Support",
draft-ietf-dime-mip6-split-02 (work in progress), May 2007.
[17] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound, "Dynamic [17] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound, "Dynamic
Updates in the Domain Name System (DNS UPDATE)", RFC 2136, Updates in the Domain Name System (DNS UPDATE)", RFC 2136,
April 1997. April 1997.
[18] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose, [18] Arends, R., Austein, R., Larson, M., Massey, D., and S. Rose,
"DNS Security Introduction and Requirements", RFC 4033, "DNS Security Introduction and Requirements", RFC 4033,
March 2005. March 2005.
[19] Vixie, P., Gudmundsson, O., Eastlake, D., and B. Wellington, [19] Vixie, P., Gudmundsson, O., Eastlake, D., and B. Wellington,
"Secret Key Transaction Authentication for DNS (TSIG)", "Secret Key Transaction Authentication for DNS (TSIG)",
RFC 2845, May 2000. RFC 2845, May 2000.
[20] Eastlake, D., "Secret Key Establishment for DNS (TKEY RR)", [20] Eastlake, D., "Secret Key Establishment for DNS (TKEY RR)",
RFC 2930, September 2000. RFC 2930, September 2000.
[21] Jang, H., "DHCP Option for Home Information Discovery in [21] Jang, H., "DHCP Option for Home Information Discovery in
MIPv6", draft-ietf-mip6-hiopt-02 (work in progress), MIPv6", draft-ietf-mip6-hiopt-05 (work in progress), June 2007.
February 2007.
[22] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509 [22] Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509
Public Key Infrastructure Certificate and Certificate Public Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile", RFC 3280, April 2002. Revocation List (CRL) Profile", RFC 3280, April 2002.
Authors' Addresses Authors' Addresses
Gerardo Giaretta Gerardo Giaretta
Qualcomm Qualcomm
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