draft-ietf-hip-dns-01.txt   draft-ietf-hip-dns-02.txt 
HIP Working Group P. Nikander Network Working Group P. Nikander
Internet-Draft Ericsson Research Nomadic Lab Internet-Draft Ericsson Research Nomadic Lab
Expires: August 21, 2005 J. Laganier Expires: January 14, 2006 J. Laganier
LIP / Sun Microsystems DoCoMo Euro-Labs
February 20, 2005 July 11, 2005
Host Identity Protocol (HIP) Domain Name System (DNS) Extensions Host Identity Protocol (HIP) Domain Name System (DNS) Extensions
draft-ietf-hip-dns-01 draft-ietf-hip-dns-02
Status of this Memo Status of this Memo
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
Abstract Abstract
This document specifies two new resource records (RRs) for the Domain This document specifies two new resource records (RRs) for the Domain
Name System (DNS), and how to use them with the Host Identity Name System (DNS), and how to use them with the Host Identity
Protocol (HIP). These RRs allow a HIP node to store in the DNS its Protocol (HIP). These RRs allow a HIP node to store in the DNS its
Host Identity (HI, the public component of the node public-private Host Identity (HI, the public component of the node public-private
key pair), Host Identity Tag (HIT, a truncated hash of its public key pair), Host Identity Tag (HIT, a truncated hash of its public
key), and the Domain Name or IP addresses of its Rendezvous Servers key), and the Domain Name or IP addresses of its Rendezvous Servers
(RVS). (RVS).
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions used in this document . . . . . . . . . . . . . . 5 2. Conventions used in this document . . . . . . . . . . . . . . 6
3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 6 3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Simple static singly homed end-host . . . . . . . . . . . 7 3.1 Simple static singly homed end-host . . . . . . . . . . . 8
3.2 Mobile end-host . . . . . . . . . . . . . . . . . . . . . 8 3.2 Mobile end-host . . . . . . . . . . . . . . . . . . . . . 9
3.3 Mixed Scenario . . . . . . . . . . . . . . . . . . . . . . 9 3.3 Mixed Scenario . . . . . . . . . . . . . . . . . . . . . . 10
4. Overview of using the DNS with HIP . . . . . . . . . . . . . . 10 4. Overview of using the DNS with HIP . . . . . . . . . . . . . . 12
4.1 Storing HI and HIT in DNS . . . . . . . . . . . . . . . . 10 4.1 Storing HI and HIT in DNS . . . . . . . . . . . . . . . . 12
4.1.1 Different types of HITs . . . . . . . . . . . . . . . 10 4.1.1 Different types of HITs . . . . . . . . . . . . . . . 12
4.2 Storing Rendezvous Servers in the DNS . . . . . . . . . . 11 4.2 Storing Rendezvous Servers in the DNS . . . . . . . . . . 13
4.3 Initiating connections based on DNS names . . . . . . . . 11 4.3 Initiating connections based on DNS names . . . . . . . . 13
5. Storage Format . . . . . . . . . . . . . . . . . . . . . . . . 12 5. Storage Format . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1 HIPHI RDATA format . . . . . . . . . . . . . . . . . . . . 12 5.1 HIPHI RDATA format . . . . . . . . . . . . . . . . . . . . 14
5.1.1 HIT type format . . . . . . . . . . . . . . . . . . . 12 5.1.1 HIT type format . . . . . . . . . . . . . . . . . . . 14
5.1.2 HIT algorithm format . . . . . . . . . . . . . . . . . 12 5.1.2 HIT algorithm format . . . . . . . . . . . . . . . . . 14
5.1.3 PK algorithm format . . . . . . . . . . . . . . . . . 12 5.1.3 PK algorithm format . . . . . . . . . . . . . . . . . 15
5.1.4 HIT format . . . . . . . . . . . . . . . . . . . . . . 13 5.1.4 HIT format . . . . . . . . . . . . . . . . . . . . . . 15
5.1.5 Public key format . . . . . . . . . . . . . . . . . . 13 5.1.5 Public key format . . . . . . . . . . . . . . . . . . 15
5.2 HIPRVS RDATA format . . . . . . . . . . . . . . . . . . . 13 5.2 HIPRVS RDATA format . . . . . . . . . . . . . . . . . . . 16
5.2.1 Preference format . . . . . . . . . . . . . . . . . . 14 5.2.1 Preference format . . . . . . . . . . . . . . . . . . 16
5.2.2 Rendezvous server type format . . . . . . . . . . . . 14 5.2.2 Rendezvous server type format . . . . . . . . . . . . 16
5.2.3 Rendezvous server format . . . . . . . . . . . . . . . 14 5.2.3 Rendezvous server format . . . . . . . . . . . . . . . 17
6. Presentation Format . . . . . . . . . . . . . . . . . . . . . 16 6. Presentation Format . . . . . . . . . . . . . . . . . . . . . 18
6.1 HIPHI Representation . . . . . . . . . . . . . . . . . . . 16 6.1 HIPHI Representation . . . . . . . . . . . . . . . . . . . 18
6.2 HIPRVS Representation . . . . . . . . . . . . . . . . . . 16 6.2 HIPRVS Representation . . . . . . . . . . . . . . . . . . 18
6.3 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 17 6.3 Examples . . . . . . . . . . . . . . . . . . . . . . . . . 19
7. Retrieving Multiple HITs and IPs from the DNS . . . . . . . . 18 7. Retrieving Multiple HITs and IPs from the DNS . . . . . . . . 20
8. Transition mechanisms . . . . . . . . . . . . . . . . . . . . 19 8. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9. Security Considerations . . . . . . . . . . . . . . . . . . . 20 8.1 Attacker tampering with an unsecure HIPHI RR . . . . . . . 21
9.1 Attacker tampering with an unsecure HIPHI RR . . . . . . . 20 8.2 Attacker tampering with an unsecure HIPRVS RR . . . . . . 21
9.2 Attacker tampering with an unsecure HIPRVS RR . . . . . . 20 8.3 Opportunistic HIP . . . . . . . . . . . . . . . . . . . . 22
9.3 Opportunistic HIP . . . . . . . . . . . . . . . . . . . . 21 8.4 Unpublished Initiator HI . . . . . . . . . . . . . . . . . 22
9.4 Unpublished Initiator HI . . . . . . . . . . . . . . . . . 21 8.5 Hash and HITs Collisions . . . . . . . . . . . . . . . . . 22
9.5 Hash and HITs Collisions . . . . . . . . . . . . . . . . . 21 8.6 DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . . . 22
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . 22 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 23 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 25
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 26
12.1 Normative references . . . . . . . . . . . . . . . . . . . . 24 11.1 Normative references . . . . . . . . . . . . . . . . . . . 26
12.2 Informative references . . . . . . . . . . . . . . . . . . . 25 11.2 Informative references . . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 27
A. Document Revision History . . . . . . . . . . . . . . . . . . 26 Intellectual Property and Copyright Statements . . . . . . . . 28
Intellectual Property and Copyright Statements . . . . . . . . 27
1. Introduction 1. Introduction
This document specifies two new resource records (RRs) for the Domain This document specifies two new resource records (RRs) for the Domain
Name System (DNS) [1], and how to use them with the Host Identity Name System (DNS) [1], and how to use them with the Host Identity
Protocol (HIP) [10]. These RRs allow a HIP node to store in the DNS Protocol (HIP) [11]. These RRs allow a HIP node to store in the DNS
its Host Identity (HI, the public component of the node its Host Identity (HI, the public component of the node public-
public-private key pair), Host Identity Tag (HIT, a truncated hash of private key pair), Host Identity Tag (HIT, a truncated hash of its
its HI), and the Domain Name or IP addresses of its Rendezvous HI), and the Domain Name or IP addresses of its Rendezvous Servers
Servers (RVS) [13]. (RVS) [14].
The current Internet architecture defines two global namespaces: IP The current Internet architecture defines two global namespaces: IP
addresses and domain names. The Domain Name System provides a two addresses and domain names. The Domain Name System provides a two
way lookup between these two namespaces. The HIP architecture [11] way lookup between these two namespaces. The HIP architecture [12]
defines a new third namespace, called the Host Identity Namespace. defines a new third namespace, called the Host Identity Namespace.
This namespace is composed of Host Identifiers (HI) of HIP nodes. This namespace is composed of Host Identifiers (HI) of HIP nodes.
The Host Identity Tag (HIT) is one representation of an HI. This The Host Identity Tag (HIT) is one representation of an HI. This
representation is obtained by taking the output of a secure hash representation is obtained by taking the output of a secure hash
function applied to the HI, truncated to the IPv6 address size. HITs function applied to the HI, truncated to the IPv6 address size. HITs
are supposed to be used in the place of IP addresses within most ULPs are supposed to be used in the place of IP addresses within most ULPs
and applications. and applications.
The Host Identity Protocol [11] allows two HIP nodes to establish
together a HIP Association. A HIP association is bound to the nodes
HIs rather than to their IP address(es).
A HIP node establish a HIP association by initiating a 4 way
handshake where two parties, the Initiatior and Responder, exchange
the I1, I2, R1 and R2 HIP packets (see section 5.3 of [11])
+-----+ +-----+ +-----+ +-----+
| |-------I1------>| | | |-------I1------>| |
| I |<------R1-------| R | | I |<------R1-------| R |
| |-------I2------>| | | |-------I2------>| |
| |<------R2-------| | | |<------R2-------| |
+-----+ +-----+ +-----+ +-----+
The Host Identity Protocol [10] allows two HIP nodes to establish
together a HIP Association. A HIP association is bound to the nodes
HIs rather than to their IP address(es).
Although a HIP node can initiate HIP communication Although a HIP node can initiate HIP communication
"opportunistically", i.e., without a priori knowledge of its peer's "opportunistically", i.e., without a priori knowledge of its peer's
HI, doing so exposes both endpoints to Man-in-the-Middle attacks on HI, doing so exposes both endpoints to Man-in-the-Middle attacks on
the HIP handshake and its cryptographic protocol. Hence, there is a the HIP handshake and its cryptographic protocol. Hence, there is a
desire to gain knowledge of peers' HI before applications and ULPs desire to gain knowledge of peers' HI before applications and ULPs
initiate communication. Because many applications use the Domain initiate communication. Because many applications use the Domain
Name System [1] to name nodes, DNSSEC [3] is a straightforward way to Name System [1] to name nodes, DNS is a straightforward way to
provision nodes with the HIP informations (i.e. HI and possibly RVS) provision nodes with the HIP informations (i.e. HI and possibly RVS)
of nodes named in the DNS tree, without introducing or relying on an of nodes named in the DNS tree, without introducing or relying on an
additional piece of infrastructure. additional piece of infrastructure. Note that without DNSSEC [3] the
Man-in-the-Middle attack evocated before has moved from the
opportunistic HIP handshake to the DNS name resolution; See also
Section 8.
The proposed HIP multi-homing mechanisms [13] allow a node to
dynamically change its set of underlying IP addresses while
maintaining IPsec SA and transport layer session survivability. The
HIP rendezvous extensions [14] proposal allows a HIP node to maintain
HIP reachability while it is changing its current location (the node
IP address(es)). This rendezvous service is provided by a third
party, the node's Rendezvous Server (RVS).
+-----+ +-----+
+--I1--->| RVS |---I1--+ +--I1--->| RVS |---I1--+
| +-----+ | | +-----+ |
| v | v
+-----+ +-----+ +-----+ +-----+
| |<------R1-------| | | |<------R1-------| |
| I |-------I2------>| R | | I |-------I2------>| R |
| |<------R2-------| | | |<------R2-------| |
+-----+ +-----+ +-----+ +-----+
The proposed HIP multi-homing mechanisms [12] allow a node to An initiator (I) willing to establish a HIP association with a
dynamically change its set of underlying IP addresses while responder (R) would typically initiate a HIP exchange by sending an
maintaining IPsec SA and transport layer session survivability. The I1 towards the RVS IP address rather than towards the responder IP
HIP rendezvous extensions [13] proposal allows a HIP node to maintain address. Then, the RVS, noticing that the receiver HIT is not its
HIP reachability while it is changing its current location (the node own, but the HIT of a HIP node registered for the rendezvous Service,
IP address(es)). This rendezvous service is provided by a third would relay the I1 to the responder. Typically the responder would
party, the node's Rendezvous Server (RVS). An initiator (I) willing then complete the exchange without further assistance from the RVS by
to establish a HIP association with a responder (R) would typically sending an R1 directly to the initiator IP address.
initiate a HIP exchange by sending an I1 towards the RVS IP address
rather than towards the responder IP address. Then, the RVS,
noticing that the receiver HIT is not its own, but the HIT of a HIP
node registered for the rendezvous Service, would relay the I1 to the
responder. Typically the responder would then complete the exchange
without further assistance from the RVS by sending an R1 directly to
the initiator IP address.
Currently, most of the Internet applications that need to communicate Currently, most of the Internet applications that need to communicate
with a remote host first translate a domain name (often obtained via with a remote host first translate a domain name (often obtained via
user input) into one or more IP address(es). This step occurs prior user input) into one or more IP address(es). This step occurs prior
to communication with the remote host, and relies on a DNS lookup. to communication with the remote host, and relies on a DNS lookup.
With HIP, IP addresses are expected to be used mostly for on-the-wire With HIP, IP addresses are expected to be used mostly for on-the-wire
communication between end hosts, while most ULPs and applications communication between end hosts, while most ULPs and applications
uses HIs or HITs instead (ICMP might be an example of an ULP not uses HIs or HITs instead (ICMP might be an example of an ULP not
using them). Consequently, we need a means to translate a domain using them). Consequently, we need a means to translate a domain
name into an HI. Using the DNS for this translation is pretty name into an HI. Using the DNS for this translation is pretty
straightforward: We define a new HIPHI (HIP HI) resource record. straightforward: We define a new HIPHI (HIP HI) resource record.
Upon query by an application or ULP for a FQDN -> IP lookup, the Upon query by an application or ULP for a FQDN -> IP lookup, the
resolver would then additionally perform an FQDN -> HI lookup, and resolver would then additionally perform an FQDN -> HI lookup, and
use it to construct the resulting HI -> IP mapping (which is internal use it to construct the resulting HI -> IP mapping (which is internal
to the HIP layer). The HIP layer uses the HI -> IP mapping to to the HIP layer). The HIP layer uses the HI -> IP mapping to
translate HIs and their local representations (HITs, IPv4 and translate HIs and their local representations (HITs, IPv4 and IPv6-
IPv6-compatible LSIs) into IP addresses and vice versa. compatible LSIs) into IP addresses and vice versa.
This draft introduces the following new DNS Resource Records: This draft introduces the following new DNS Resource Records:
- HIPHI, for storing Host Identifiers and Host Identity Tags - HIPHI, for storing Host Identifiers and Host Identity Tags
- HIPRVS, for storing rendezvous server information - HIPRVS, for storing rendezvous server information
2. Conventions used in this document 2. Conventions used in this document
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 RFC2119 [4]. document are to be interpreted as described in RFC2119 [4].
3. Usage Scenarios 3. Usage Scenarios
skipping to change at page 6, line 20 skipping to change at page 7, line 20
With HIP, most application and ULPs are unaware of the IP addresses With HIP, most application and ULPs are unaware of the IP addresses
used to carry packets on the wire. Consequently, a HIP node could used to carry packets on the wire. Consequently, a HIP node could
take advantage of having multiple IP addresses for fail-over, take advantage of having multiple IP addresses for fail-over,
redundancy, mobility, or renumbering, in a manner which is redundancy, mobility, or renumbering, in a manner which is
transparent to most ULPs and applications (because they are bound to transparent to most ULPs and applications (because they are bound to
HIs, hence they are agnostic to these IP address changes). HIs, hence they are agnostic to these IP address changes).
In these situations, a node wishing to be reachable by reference to In these situations, a node wishing to be reachable by reference to
its FQDN should store the following informations in the DNS: its FQDN should store the following informations in the DNS:
o A set of IP address(es). o A set of IP address(es) through A and AAAA RRs.
o A Host Identity (HI) and/or Host Identity Tag (HIT).
o An IP address or DNS name of its Rendezvous Server(s) (RVS). o A Host Identity (HI) and/or Host Identity Tag (HIT) through HIPHI
RRs.
o An IP address or DNS name of its Rendezvous Server(s) (RVS)
through HIPRVS RRs.
When a HIP node wants to initiate a communication with another HIP When a HIP node wants to initiate a communication with another HIP
node, it first needs to perform a HIP base exchange to set-up a HIP node, it first needs to perform a HIP base exchange to set-up a HIP
association towards its peer. Although such an exchange can be association towards its peer. Although such an exchange can be
initiated opportunistically, i.e., without a priori knowledge of the initiated opportunistically, i.e., without a priori knowledge of the
responder's HI, by doing so both nodes knowingly risk responder's HI, by doing so both nodes knowingly risk man-in-the-
man-in-the-middle attacks on the HIP exchange. To prevent these middle attacks on the HIP exchange. To prevent these attacks, it is
attacks, it is recommended that the initiator first obtain the HI of recommended that the initiator first obtain the HI of the responder,
the responder, and then initiate the exchange. This can be done, for and then initiate the exchange. This can be done, for example,
example, through manual configuration or DNS lookups. Hence, a new through manual configuration or DNS lookups. Hence, a new HIPHI RR
HIPHI RR is introduced. is introduced.
When a HIP node is frequently changing its IP address(es), the When a HIP node is frequently changing its IP address(es), the
dynamic DNS update latency may prevent it from publishing its new IP dynamic DNS update latency may prevent it from publishing its new IP
address(es) in the DNS. For solving this problem, the HIP address(es) in the DNS. For solving this problem, the HIP
architecture introduces Rendezvous Servers (RVS). A HIP host uses a architecture introduces Rendezvous Servers (RVS). A HIP host uses a
Rendezvous Server as a Rendezvous point, to maintain reachability Rendezvous Server as a Rendezvous point, to maintain reachability
with possible HIP initiators. Such a HIP node would publish in the with possible HIP initiators. Such a HIP node would publish in the
DNS its RVS IP address or DNS name in a HIPRVS RR, while keeping its DNS its RVS IP address or DNS name in a HIPRVS RR, while keeping its
RVS up-to-date with its current set of IP addresses. RVS up-to-date with its current set of IP addresses.
Then, when some other node wants to initiate a HIP exchange with such When a HIP node wants to initiate a HIP exchange with a responder it
a responder, it retrieves the RVS IP address by looking up a HIPRVS will perform a number of DNS lookups. First the initiator will need
RR at the FQDN of the responder, and sends an I1 to this IP address. to query for an A or AAAA record at the responders FQDN.
The I1 will then be relayed by the RVS to the responder, which will
then complete the HIP exchange, either directly or via the RVS [13]. If the query for the A and/or AAAA was responded to with a DNS answer
with RCODE=3 (Name Error), then the responder's information is not
present in the DNS and further queries SHOULD NOT be made.
In case the query for the address records returned a DNS answer with
RCODE=0 (No Error), then the initiator sends out two queries: One for
the HIPHI type and one for the HIPRVS type at the responder's FQDN.
Depending on the combinations of answer the situations described in
Section 3.1, Section 3.2 and Section 3.3 can occur.
Note that storing HIP RR information in the DNS at a FQDN which is Note that storing HIP RR information in the DNS at a FQDN which is
assigned to a non-HIP node might have ill effects on its reachability assigned to a non-HIP node might have ill effects on its reachability
by HIP nodes. by HIP nodes.
3.1 Simple static singly homed end-host 3.1 Simple static singly homed end-host
A HIP node (R) with a single static network attachment, wishing to be
reachable by reference to its FQDN (www.example.com), would store in
the DNS, in addition to its IP address(es) (IP-R), its Host Identity
(HI-R) in a HIPHI resource record.
An initiator willing to associate with a node would typically issue
the following queries:
QNAME=www.example.com, QTYPE=A
(QCLASS=IN is assumed and ommitted from the examples)
Which returns a DNS packet with RCODE=0 and one or more A RRs A with
the address of the responder (e.g. IP-R) in the answer section.
QNAME=www.example.com, QTYPE=HIPHI
Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs
with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the
answer section.
QNAME=www.example.com, QTYPE=HIPRVS
Which returns a DNS packet with RCODE=0 and an empty answer section.
Caption: In the remainder of this document, for the sake of keeping
diagrams simple and concise, several DNS queries and answers
are represented as one single transaction, while in fact
there are several queries and answers flowing back and
forth, as described in the textual examples.
[A? HIPRVS? HIPHI?] [A? HIPRVS? HIPHI?]
[www.example.com ] +-----+ [www.example.com ] +-----+
+-------------------------------->| | +-------------------------------->| |
| | DNS | | | DNS |
| +-------------------------------| | | +-------------------------------| |
| | [A? HIPRVS? HIPHI? ] +-----+ | | [A? HIPRVS? HIPHI? ] +-----+
| | [www.example.com ] | | [www.example.com ]
| | [A IP-R ] | | [A IP-R ]
| | [HIPHI 10 3 2 HIT-R HI-R] | | [HIPHI 10 3 2 HIT-R HI-R]
| v | v
+-----+ +-----+ +-----+ +-----+
| |--------------I1------------->| | | |--------------I1------------->| |
| I |<-------------R1--------------| R | | I |<-------------R1--------------| R |
| |--------------I2------------->| | | |--------------I2------------->| |
| |<-------------R2--------------| | | |<-------------R2--------------| |
+-----+ +-----+ +-----+ +-----+
A HIP node (R) with a single static network attachment, wishing to be
reachable by reference to its FQDN (www.example.com), would store in
the DNS, in addition to its IP address(es) (IP-R), its Host Identity
(HI-R) in a HIPHI resource record.
3.2 Mobile end-host 3.2 Mobile end-host
A mobile HIP node (R) wishing to be reachable by reference to its
FQDN (www.example.com) would store in the DNS, possibly in addition
to its IP address(es) (IP-R), its HI (HI-R) in a HIPHI RR, and the IP
address(es) of its Rendezvous Server(s) (IP-RVS) in HIPRVS resource
record(s). The mobile HIP node also need to notify its Rendezvous
Servers of any change in its set of IP address(es).
An initiator willing to associate with such mobile node would
typically issue the following queries:
QNAME=www.example.com, QTYPE=A
Which returns a DNS packet with RCODE=0 and an empty answer section.
QNAME=www.example.com, QTYPE=HIPHI
Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs
with the HIT and HI (e.g HIT-R and HI-R) of the responder in the
answer section.
QNAME=www.example.com, QTYPE=HIPRVS
Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs
containing IP address(es) (e.g IP-RVS) or FQDN(s) of RVS(s).
[A? HIPRVS? HIPHI?] [A? HIPRVS? HIPHI?]
[www.example.com ] +-----+ [www.example.com ] +-----+
+--------------------------------->| | +--------------------------------->| |
| | DNS | | | DNS |
| +--------------------------------| | | +--------------------------------| |
| | [A? HIPRVS? HIPHI? ] +-----+ | | [A? HIPRVS? HIPHI? ] +-----+
| | [www.example.com ] | | [www.example.com ]
| | [HIPRVS 1 2 IP-RVS ] | | [HIPRVS 1 2 IP-RVS ]
| | [HIPHI 10 3 2 HIT-R HI-R] | | [HIPHI 10 3 2 HIT-R HI-R]
| | | |
skipping to change at page 8, line 29 skipping to change at page 10, line 32
| | | +-----+ | | | | +-----+ |
| | | | | | | |
| | | | | | | |
| v | v | v | v
+-----+ +-----+ +-----+ +-----+
| |<---------------R1------------| | | |<---------------R1------------| |
| I |----------------I2----------->| R | | I |----------------I2----------->| R |
| |<---------------R2------------| | | |<---------------R2------------| |
+-----+ +-----+ +-----+ +-----+
A mobile HIP node (R) wishing to be reachable by reference to its The initiator would then send an I1 to one of its RVS. Following,
FQDN (www.example.com) would store in the DNS, possibly in addition the RVS will relay the I1 up to the mobile node, which will complete
to its IP address(es) (IP-R), its HI (HI-R) in a HIPHI RR, and the IP the HIP exchange.
address(es) of its Rendezvous Server(s) (IP-RVS) in HIPRVS resource
record(s). The mobile HIP node also need to notify its Rendezvous
Servers of any change in its set of IP address(es).
A host wanting to reach this mobile host would then send an I1 to one
of its RVS. Following, the RVS will relay the I1 up to the mobile
node, which will complete the HIP exchange.
3.3 Mixed Scenario 3.3 Mixed Scenario
A HIP node might be configured with more than one IP address (multi-
homed), or Rendezvous Server (multi-reachable). In these cases, it
is possible that the DNS returns multiple A or AAAA RRs, as well as
HIPRVS containing one or multiple Rendezvous Servers. In addition to
its set of IP address(es) (IP-R1, IP-R2), a multi-homed end-host
would store in the DNS its HI (HI-R) in a HIPHI RR, and possibly the
IP address(es) of its RVS(s) (IP-RVS1, IP-RVS2) in HIPRVS RRs.
An initiator willing to associate with such a node would typically
issue the following queries:
QNAME=www.example.com, QTYPE=A
Which returns a DNS packet with RCODE=0 and one or more A or AAAA RRs
containing IP address(es) (e.g IP-R1 and IP-R2) in the answer
section.
QNAME=www.example.com, QTYPE=HIPHI
Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs
with the HIT and HI (e.g HIT-R and HI-R) of the responder in the
answer section.
QNAME=www.example.com, QTYPE=HIPRVS
Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs
containing IP address(es) (e.g IP-RVS1, IP-RVS2) or FQDN(s) of
RVS(s).
[A? HIPRVS? HIPHI?] [A? HIPRVS? HIPHI?]
[www.example.com ] +-----+ [www.example.com ] +-----+
+--------------------------------->| | +--------------------------------->| |
| | DNS | | | DNS |
| +--------------------------------| | | +--------------------------------| |
| | [A? HIPRVS? HIPHI? ] +-----+ | | [A? HIPRVS? HIPHI? ] +-----+
| | [www.example.com ] | | [www.example.com ]
| | [A IP-R1 ] | | [A IP-R1 ]
| | [A IP-R2 ] | | [A IP-R2 ]
| | [HIPRVS 1 2 IP-RVS1 ] | | [HIPRVS 1 2 IP-RVS1 ]
skipping to change at page 9, line 36 skipping to change at page 12, line 5
| | | | | | | |
| I |<--------------R1--------------| R | | I |<--------------R1--------------| R |
| |---------------I2------------->| | | |---------------I2------------->| |
| |<--------------R2--------------| | | |<--------------R2--------------| |
+-----+ +-----+ +-----+ +-----+
| ^ | ^
| +------+ | | +------+ |
+-----I1----->| RVS2 |------I1------+ +-----I1----->| RVS2 |------I1------+
+------+ +------+
A HIP node might be configured with more than one IP address
(multi-homed), or Rendezvous Server (multi-reachable). In these
cases, it is possible that the DNS returns multiples A or AAAA RRs,
as well as HIPRVS containing one or multiple Rendezvous Servers. In
addition to its set of IP address(es) (IP-R1, IP-R2), a multi-homed
end-host would store in the DNS its HI (HI-R) in a HIPHI RR, and
possibly the IP address(es) of its RVS(s) (IP-RVS1, IP-RVS2) in
HIPRVS RRs.
4. Overview of using the DNS with HIP 4. Overview of using the DNS with HIP
4.1 Storing HI and HIT in DNS 4.1 Storing HI and HIT in DNS
Any conforming implementation may store Host Identifiers in a DNS Any conforming implementation may store Host Identifiers in a DNS
HIPHI RDATA format. An implementation may also store a HIT along HIPHI RDATA format. An implementation may also store a HIT along
with its associated HI. If a particular form of an HI or HIT does with its associated HI. If a particular form of an HI or HIT does
not already have a specified RDATA format, a new RDATA-like format not already have a specified RDATA format, a new RDATA-like format
SHOULD be defined for the HI or HIT. SHOULD be defined for the HI or HIT.
4.1.1 Different types of HITs 4.1.1 Different types of HITs
There are _currently_ two types of HITs. HITs of the first type There are two types of HITs. HITs of the first type, called Type 1
consists just of the least significant bits of the hash of the public HIT, consist of an 8-bit prefix followed by 120 bits of the hash of
key. HITs of the second type consist of a binary prefix Host the public key. HITs of the second type (Type 2 HIT) consist of a
Assigning Authority (HAA) field, and only the last bits come from a Host Assigning Authority Field (HAA), and only the last 64 bits come
hash of the Host Identity. This latter format for HIT is recommended from a SHA-1 hash of the Host Identity. This latter format for HIT
for 'well known' systems. It is possible to support a resolution is recommended for 'well known' systems. It is possible to support a
mechanism for these names in directories like DNS. resolution mechanism for these names in hierarchical directories,
like the DNS.
Note that the format how HITs are stored in the DNS may be different This document fully specifies only Type 2 HITs. Type 1 HITs are
form the format actually used in protocols, the HIP base exchange specified in Section 3.1 of [11].
[10] included. This is because the DNS RR explicitly contains the
HIT type and algorithm, while some protocols may prefer to use a Note that the format how HITs are stored in the HIPHI RRs may be
prefix to indicate the HIT type. The implementations are expected to different form the format actually used in protocols, the HIP base
use the actual HI when comparing Host Identities. exchange [11] included. This is because the DNS RR explicitly
contains the HIT type and algorithm, while some protocols may prefer
to use a prefix to indicate the HIT type. The implementations are
expected to use the actual HI when comparing Host Identities.
4.1.1.1 Host Assigning Authority (HAA) field 4.1.1.1 Host Assigning Authority (HAA) field
The 64 bits of HAA supports two levels of delegation. The first is a The 64 bits of HAA supports two levels of delegation. The first is a
registered assigning authority (RAA). The second is a registered registered assigning authority (RAA). The second is a registered
identity (RI, commonly a company). The RAA is 24 bits with values identity (RI, commonly a company). The RAA is 24 bits with values
assign sequentially by ICANN. The RI is 40 bits, also assigned assign sequentially by ICANN. The RI is 40 bits, also assigned
sequentially but by the RAA. sequentially but by the RAA.
4.1.1.2 Storing HAA in DNS 4.1.1.2 Storing HAA in HIPHI Resource Records
Any conforming implementation may store a domain name Host Assigning Any conforming implementation may store a domain name Host Assigning
Authority (HAA) in a DNS HIPHI RDATA format. A HAA MUST be stored Authority (HAA) in a DNS HIPHI RDATA format. A HAA MUST be stored
like a Type 2 HIT, while the least significant bits of the HIT like a Type 2 HIT, while the least significant bits of the HIT
extracted from the HI hash output are set to zero, the Host Identity extracted from the HI hash output are set to zero, the Host Identity
Length is set zero, and the Host Identity field is omitted. If a Length is set zero, and the Host Identity field is omitted. If a
particular form of a HAA does not already have an associated HIT particular form of a HAA does not already have an associated HIT
specified RDATA format, a new RDATA-like format SHOULD be defined for specified RDATA format, a new RDATA-like format SHOULD be defined for
the HIT/HAA. the HIT/HAA.
4.1.1.3 HI and HIT verification 4.1.1.3 HI and HIT verification
Upon return of a HIPHI RR, a host MUST always calculate the Upon return of a HIPHI RR, a host MUST always calculate the HI-
HI-derivative HIT to be used in the HIP exchange, as specified in the derivative HIT to be used in the HIP exchange, as specified in the
HIP architecture [11], while the HIT possibly embedded along SHOULD HIP architecture [12], while the HIT possibly embedded along SHOULD
only be used as an optimization (e.g. table lookup). only be used as an optimization (e.g. table lookup).
4.2 Storing Rendezvous Servers in the DNS 4.2 Storing Rendezvous Servers in the DNS
The HIP Rendezvous server (HIPRVS) resource record indicates an The HIP Rendezvous server (HIPRVS) resource record indicates an
address or a domain name of a RendezVous Server, towards which a HIP address or a domain name of a RendezVous Server, towards which a HIP
I1 packet might be sent to trigger the establishment of an I1 packet might be sent to trigger the establishment of an
association with the entity named by this resource record [13]. association with the entity named by this resource record [14].
An RVS receiving such an I1 would then relay it to the appropriate An RVS receiving such an I1 would then relay it to the appropriate
responder (the owner of the I1 receiver HIT). The responder will responder (the owner of the I1 receiver HIT). The responder will
then complete the exchange with the initiator, typically without then complete the exchange with the initiator, typically without
ongoing help from the RVS. ongoing help from the RVS.
Any conforming implementation may store Rendezvous Server's IP Any conforming implementation may store Rendezvous Server's IP
address(es) or DNS name in a DNS HIPRVS RDATA format. If a address(es) or DNS name in a DNS HIPRVS RDATA format. If a
particular form of a RVS reference does not already have a specified particular form of a RVS reference does not already have a specified
RDATA format, a new RDATA-like format SHOULD be defined for the RVS. RDATA format, a new RDATA-like format SHOULD be defined for the RVS.
4.3 Initiating connections based on DNS names 4.3 Initiating connections based on DNS names
On a HIP node, a Host Identity Protocol exchange SHOULD be initiated On a HIP node, a Host Identity Protocol exchange SHOULD be initiated
whenever an Upper Layer Protocol attempt to communicate with an whenever an Upper Layer Protocol attempt to communicate with an
entity and the DNS lookup returns HIPHI and/or HIPRVS resource entity and the DNS lookup returns HIPHI and/or HIPRVS resource
records. If a DNS lookup returns one or more HIPRVS RRs and no A nor records. If a DNS lookup returns one or more HIPRVS RRs and no A nor
AAAA RRs, the afore mentioned HIP exchange SHOULD be initiated AAAA RRs, the afore mentioned HIP exchange SHOULD be initiated
towards one of these RVS [10]. Since some hosts may choose not to towards one of these RVS [11]. Since some hosts may choose not to
have HIPHI information in DNS, hosts MAY implement support for have HIPHI information in DNS, hosts MAY implement support for
opportunistic HIP. opportunistic HIP.
5. Storage Format 5. Storage Format
5.1 HIPHI RDATA format 5.1 HIPHI RDATA format
The RDATA for a HIPHI RR consists of a HIT type, an algorithm type, a The RDATA for a HIPHI RR consists of a HIT type, an algorithm type, a
HIT, and a public key. HIT, and a public key.
skipping to change at page 12, line 45 skipping to change at page 15, line 6
7 A HAA is present 7 A HAA is present
5.1.2 HIT algorithm format 5.1.2 HIT algorithm format
The HIT algorithm indicates the hash algorithm used to generate the The HIT algorithm indicates the hash algorithm used to generate the
Host Identity Tag (HIT) from the HI. Host Identity Tag (HIT) from the HI.
The following values are defined: The following values are defined:
0 Reserved 0 Reserved
1 SHA1 1 SHA1
2-255 Unassigned 2-255 Unassigned
5.1.3 PK algorithm format 5.1.3 PK algorithm format
The PK algorithm field indicates the public key cryptographic The PK algorithm field indicates the public key cryptographic
algorithm and the implied public key field format. This document algorithm and the implied public key field format. This document
reuse the values defined for the 'algorithm type' of the IPSECKEY RR reuse the values defined for the 'algorithm type' of the IPSECKEY RR
[14] 'gateway type' field. [10] 'gateway type' field.
The presently defined values are given only informally: The presently defined values are given only informally:
1 A DSA key is present, in the format defined in RFC2536 [5]. 1 A DSA key is present, in the format defined in RFC2536 [5].
2 A RSA key is present, in the format defined in RFC3110 [6]. 2 A RSA key is present, in the format defined in RFC3110 [6].
5.1.4 HIT format 5.1.4 HIT format
There's currently two types of HITs, and a single type of HAA. Both There's currently two types of HITs, and a single type of HAA. Both
of them are stored in network byte order within a self-describing of them are stored in network byte order within a self-describing
variable length wire-encoded <character-string> (as per Section 3.3 variable length wire-encoded <character-string> (as per Section 3.3
of [2]): of [2]):
o A *Type 1* HIT: least significant bits of the hash (e.g., SHA1) of o A *Type 1* HIT: least significant bits of the hash (e.g. SHA1) of
the public key (Host Identity), which is possibly following in the the public key (Host Identity), which is possibly following in the
HIPHI RR. HIPHI RR.
o A *Type 2* HIT: binary prefix (HAA) concatenated with a the least o A *Type 2* HIT: binary prefix (HAA) concatenated with a the least
significant bits of the hash (e.g., SHA1) of the public key (Host significant bits of the hash (e.g. SHA1) of the public key (Host
Identity), which is possibly following in the HIPHI RR. Identity), which is possibly following in the HIPHI RR.
o A HAA: binary prefix (HAA) concatenated with 0, up to the o A HAA: binary prefix (HAA) concatenated with 0, up to the
associated HIT length. associated HIT length.
5.1.5 Public key format 5.1.5 Public key format
Both of the public key types defined in this document (RSA and DSA) Both of the public key types defined in this document (RSA and DSA)
reuse the public key formats defined for the IPSECKEY RR [14] (which reuse the public key formats defined for the IPSECKEY RR [10] (which
in turns contains the algorithm-specific portion of the KEY RR RDATA, in turns contains the algorithm-specific portion of the KEY RR RDATA,
all of the KEY RR DATA after the first four octets, corresponding to all of the KEY RR DATA after the first four octets, corresponding to
the same portion of the KEY RR that must be specified by documents the same portion of the KEY RR that must be specified by documents
that define a DNSSEC algorithm). that define a DNSSEC algorithm).
In the future, if a new algorithm is to be used both by IPSECKEY RR In the future, if a new algorithm is to be used both by IPSECKEY RR
and HIPHI RR, it would probably use the same public key encodings for and HIPHI RR, it would probably use the same public key encodings for
both RRs. Unless specified otherwise, the HIPHI public key field both RRs. Unless specified otherwise, the HIPHI public key field
would use the same public key format as the IPSECKEY RR RDATA for the would use the same public key format as the IPSECKEY RR RDATA for the
corresponding algorithm. corresponding algorithm.
The DSA key format is defined in RFC2536 [5]. The DSA key format is defined in RFC2536 [5].
The RSA key format is defined in RFC3110 [6] and the RSA key size The RSA key format is defined in RFC3110 [6] and the RSA key size
limit (4096 bits) is relaxed in the IPSECKEY RR [14] specification. limit (4096 bits) is relaxed in the IPSECKEY RR [10] specification.
5.2 HIPRVS RDATA format 5.2 HIPRVS RDATA format
The RDATA for a HIPRVS RR consists of a preference value, a The RDATA for a HIPRVS RR consists of a preference value, a
Rendezvous server type and either one or more Rendezvous server Rendezvous server type and either one or more Rendezvous server
address, or one Rendezvous server domain name. address, or one Rendezvous server domain name.
0 1 2 3 0 1 2 3
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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| preference | type | | | preference | type | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Rendezvous server | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Rendezvous server |
~ ~ ~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5.2.1 Preference format 5.2.1 Preference format
This is an unsigned 8-bit value, used to specify the preference given This is an unsigned 8-bit value, used to specify the preference given
to this RR amongst others at the same owner. Lower values are to the RVS in the HIPRVS RR amongst others at the same owner. RVSs
preferred. If there is a tie within some RR subset, the server with lower values are preferred. If there is a tie within some RR
should return a permutation (e.g. round robin) of the set of RRs, subset, the initiating HIP host should pick one of the RVS randomly
such that the requester load is fairly balanced amongst all RRs of from the set of RRs, such that the requester load is fairly balanced
the set. amongst all RVSs of the set.
5.2.2 Rendezvous server type format 5.2.2 Rendezvous server type format
The Rendezvous server type indicates the format of the information The Rendezvous server type indicates the format of the information
stored in the Rendezvous server field. stored in the Rendezvous server field.
This document reuses the type values for the 'gateway type' field of This document reuses the type values for the 'gateway type' field of
the IPSECKEY RR [14]. The presently defined values are given only the IPSECKEY RR [10]. The presently defined values are given only
informally: informally:
1. One or more 4-byte IPv4 address(es) in network byte order are 1. One or more 4-byte IPv4 address(es) in network byte order are
present. present.
2. One or more 16-byte IPv6 address(es) in network byte order are 2. One or more 16-byte IPv6 address(es) in network byte order are
present. present.
3. One or more variable length wire-encoded domain names as 3. One or more variable length wire-encoded domain names as
described in section 3.3 of RFC1035 [2]. The wire-encoded format described in section 3.3 of RFC1035 [2]. The wire-encoded format
is self-describing, so the length is implicit. The domain names is self-describing, so the length is implicit. The domain names
MUST NOT be compressed. MUST NOT be compressed.
5.2.3 Rendezvous server format 5.2.3 Rendezvous server format
The Rendezvous server field indicates one or more Rendezvous The Rendezvous server field indicates one or more Rendezvous
Server(s) IP address(es), or domain name(s). A HIP I1 packet sent to Server(s) IP address(es), or domain name(s). A HIP I1 packet sent to
any of these RVS would reach the entity named by this resource any of these RVS would reach the entity named by this resource
skipping to change at page 14, line 50 skipping to change at page 17, line 21
MUST NOT be compressed. MUST NOT be compressed.
5.2.3 Rendezvous server format 5.2.3 Rendezvous server format
The Rendezvous server field indicates one or more Rendezvous The Rendezvous server field indicates one or more Rendezvous
Server(s) IP address(es), or domain name(s). A HIP I1 packet sent to Server(s) IP address(es), or domain name(s). A HIP I1 packet sent to
any of these RVS would reach the entity named by this resource any of these RVS would reach the entity named by this resource
record. record.
This document reuses the format used for the 'gateway' field of the This document reuses the format used for the 'gateway' field of the
IPSECKEY RR [14], but allows to concatenate several IP (v4 or v6) IPSECKEY RR [10], but allows to concatenate several IP (v4 or v6)
addresses. The presently defined formats for the data portion of the addresses. The presently defined formats for the data portion of the
Rendezvous server field are given only informally: Rendezvous server field are given only informally:
o One or more 32-bit IPv4 address(es) in network byte order. o One or more 32-bit IPv4 address(es) in network byte order.
o One or more 128-bit IPv6 address(es) in network byte order. o One or more 128-bit IPv6 address(es) in network byte order.
o One or more variable length wire-encoded domain names as described o One or more variable length wire-encoded domain names as described
in section 3.3 of RFC1035 [2]. The wire-encoded format is in section 3.3 of RFC1035 [2]. The wire-encoded format is self-
self-describing, so the length is implicit. The domain names MUST describing, so the length is implicit. The domain names MUST NOT
NOT be compressed. be compressed.
6. Presentation Format 6. Presentation Format
This section specifies the representation of the HIPHI and HIPRVS RR This section specifies the representation of the HIPHI and HIPRVS RR
in a zone data master file. in a zone data master file.
6.1 HIPHI Representation 6.1 HIPHI Representation
The HIT Type, HIT algorithm, PK algorithm, and Public Key are The HIT Type, HIT algorithm, PK algorithm, HIT and Public Key are
REQUIRED. The HIT field is OPTIONAL. REQUIRED.
The HIT Type, HIT algorithm, and PK algorithm are represented as The HIT Type, HIT algorithm, and PK algorithm are represented as
unsigned integers. unsigned integers.
The HIT field is represented as the Base16 encoding [8] (a.k.a. hex The HIT field is represented as the Base16 encoding [8] (a.k.a. hex
or hexadecimal) of the public key. If no HIT is to be indicated, or hexadecimal) of the public key hash. The encoding MUST NOT
then the HIT algorithm MUST be zero and the HIT field must be ".". contains whitespace. If no HIT is to be indicated, then the HIT
algorithm MUST be zero and the HIT field must be "." (a single dot
character).
The Public Key field is represented as the Base64 encoding [8] of the The Public Key field is represented as the Base64 encoding [8] of the
public key. public key. The encoding MAY contains whitespace(s), and such
whitespaces MUST be ignored.
The complete representation of the HPIHI record is: The complete representation of the HPIHI record is:
IN HIPHI ( hit-type hit-algorithm pk-algorithm IN HIPHI ( hit-type hit-algorithm pk-algorithm
base16-encoded-hit base16-encoded-hit
base64-encoded-public-key ) base64-encoded-public-key )
6.2 HIPRVS Representation 6.2 HIPRVS Representation
The Preference and RVS Type fields are REQUIRED. At least one RVS The Preference and RVS Type fields are REQUIRED. At least one RVS
skipping to change at page 17, line 11 skipping to change at page 19, line 16
rendezvous-server[1] rendezvous-server[1]
... ...
rendezvous-server[n] ) rendezvous-server[n] )
6.3 Examples 6.3 Examples
Example of a node with a HI but no HIT: Example of a node with a HI but no HIT:
www.example.com IN HIPHI ( 0 1 2 www.example.com IN HIPHI ( 0 1 2
. .
AB3NzaC1kc3MAAACBAOBhKnTCPOuFBzZQX/N3O9dm9P9ivUIMoId== ) AB3NzaC1kc3MAAACBAOBhKn
TCPOuFBzZQX/N3O9dm9P9iv
UIMoId== )
Example of a node with a HI and a HIT: Example of a node with a HI and a HIT:
www.example.com IN HIPHI ( 1 1 2 www.example.com IN HIPHI ( 1 1 2
120cf10ea842e0ba53320f1fe0ba5d3a3 AB3NzaC1kc3MAAACBAOBhKn
AB3NzaC1kc3MAAACBAOBhKnTCPOuFBzZQX/N3O9dm9P9ivUIMoId== ) TCPOuFBzZQX/N3O9dm9P9iv
UIMoId== )
Example of a node with an IPv6 RVS: Example of a node with an IPv6 RVS:
www.example.com IN HIPRVS ( 10 2 2001:0db8:0200:1:20c:f1ff:fe0b:a533 ) www.example.com IN HIPRVS (10 2 2001:db8:200:1:20c:f1ff:feb:a533 )
Example of a node with three IPv4 RVS: Example of a node with three IPv4 RVS:
www.example.com IN HIPRVS ( 10 1 192.0.2.2 192.0.99.2 192.0.199.2) www.example.com IN HIPRVS ( 10 1 192.0.1.2 192.0.2.2 192.0.3.2 )
Example of a node with two named RVS: Example of a node with two named RVS:
www.example.com IN HIPRVS ( 10 3 rvs.uk.example.com rvs.us.example.com ) www.example.com IN HIPRVS ( 10 3 rvs.uk.example.com
rvs.us.example.com )
7. Retrieving Multiple HITs and IPs from the DNS 7. Retrieving Multiple HITs and IPs from the DNS
If a host receives multiple HITs in a response to a DNS query, those If a host receives multiple HITs in a response to a DNS query, those
HITs MUST be considered to denote a single service, and be HITs MUST be considered to denote a single service, and be
semantically equivalent from that point of view. When initiating a semantically equivalent from that point of view. When initiating a
base exchange with the denoted service, the host SHOULD be prepared base exchange with the denoted service, the host SHOULD be prepared
to accept any of HITs as the peer's identity. A host MAY implement to accept any of HITs as the peer's identity. A host MAY implement
this by using the opportunistic mode (destination HIT null in I1), or this by using the opportunistic mode (destination HIT null in I1), or
by sending multiple I1s, if needed. by sending multiple I1s, if needed.
skipping to change at page 18, line 34 skipping to change at page 20, line 34
It is RECOMMENDED that if a host receives multiple HITs, the host It is RECOMMENDED that if a host receives multiple HITs, the host
SHOULD first try to initiate the base exchange by using the SHOULD first try to initiate the base exchange by using the
opportunistic mode. If the returned HIT does not match with any of opportunistic mode. If the returned HIT does not match with any of
the expected HITs, the host SHOULD retry by sending further I1s, one the expected HITs, the host SHOULD retry by sending further I1s, one
at time, trying out all of the listed HITs. If the host receives an at time, trying out all of the listed HITs. If the host receives an
R1 for any of the I1s, the host SHOULD continue to use the successful R1 for any of the I1s, the host SHOULD continue to use the successful
IP address until an R1 with a listed HIT is received, or the host has IP address until an R1 with a listed HIT is received, or the host has
tried all HITs, and try the other IP addresses only after that. A tried all HITs, and try the other IP addresses only after that. A
host MAY also send multiple I1s in parallel, but sending such I1s host MAY also send multiple I1s in parallel, but sending such I1s
MUST be rate limited to avoid flooding (as per Section 8.4.1 of MUST be rate limited to avoid flooding (as per Section 8.4.1 of
[10]). [11]).
8. Transition mechanisms
During a transition period, to allows to store the HIP informations
of a node in a DNS server which does not support the HIPHI and HIPRVS
RRs, A and AAAA RRs MAY be overloaded. A HIT would typically be
stored in a AAAA RR and a RVS in either a A or AAAA RR. If such a
situation occurs, the overloaded RRs MUST be returned as the last
items of the returned RRs set (A or AAAA), to avoid as most as
possible conflicts with non-HIP IPv6 nodes.
9. Security Considerations 8. Security Considerations
Though the security considerations of the HIP DNS extensions still Though the security considerations of the HIP DNS extensions still
need to be more investigated and documented, this section contains a need to be more investigated and documented, this section contains a
description of the known threats involved with the usage of the HIP description of the known threats involved with the usage of the HIP
DNS extensions. DNS extensions.
In a manner similar to the IPSECKEY RR [14], the HIP DNS Extensions In a manner similar to the IPSECKEY RR [10], the HIP DNS Extensions
allows to provision two HIP nodes with the public keying material allows to provision two HIP nodes with the public keying material
(HI) of their peer. These HIs will be subsequently used in a key (HI) of their peer. These HIs will be subsequently used in a key
exchange between the peers. Hence, the HIP DNS Extensions introduce exchange between the peers. Hence, the HIP DNS Extensions introduce
the same kind of threats that IPSECKEY does, plus threats caused by the same kind of threats that IPSECKEY does, plus threats caused by
the possibility given to a HIP node to initiate or accept a HIP the possibility given to a HIP node to initiate or accept a HIP
exchange using "Opportunistic" or "Unpublished Initiator HI" modes. exchange using "Opportunistic" or "Unpublished Initiator HI" modes.
A HIP node SHOULD obtain both the HIPHI and HIPRVS RRs from a trusted A HIP node SHOULD obtain both the HIPHI and HIPRVS RRs from a trusted
party trough a secure channel insuring proper data integrity of the party trough a secure channel insuring proper data integrity of the
RRs. DNSSEC [3] provides such a secure channel. RRs. DNSSEC [3] provides such a secure channel.
In the absence of a proper secure channel, both parties are In the absence of a proper secure channel, both parties are
vulnerable to MitM and DoS attacks, and unrelated parties might be vulnerable to MitM and DoS attacks, and unrelated parties might be
subject to DoS attacks as well. These threats are described in the subject to DoS attacks as well. These threats are described in the
following sections. following sections.
9.1 Attacker tampering with an unsecure HIPHI RR 8.1 Attacker tampering with an unsecure HIPHI RR
The HIPHI RR contains public keying material in the form of the named The HIPHI RR contains public keying material in the form of the named
peer's public key (the HI) and its secure hash (the HIT). Both of peer's public key (the HI) and its secure hash (the HIT). Both of
these are not sensitive to attacks where an adversary gains knowledge these are not sensitive to attacks where an adversary gains knowledge
of them. However, an attacker that is able to mount an active attack of them. However, an attacker that is able to mount an active attack
on the DNS, i.e., tampers with this HIPHI RR (e.g., using DNS on the DNS, i.e., tampers with this HIPHI RR (e.g. using DNS
spoofing) is able to mount Man-in-the-Middle attacks on the spoofing) is able to mount Man-in-the-Middle attacks on the
cryptographic core of the eventual HIP exchange (responder's HIPHI cryptographic core of the eventual HIP exchange (responder's HIPHI
and HIPRVS rewritten by the attacker). and HIPRVS rewritten by the attacker).
9.2 Attacker tampering with an unsecure HIPRVS RR 8.2 Attacker tampering with an unsecure HIPRVS RR
The HIPRVS RR contains a destination IP address where the named peer The HIPRVS RR contains a destination IP address where the named peer
is reachable by an I1 (HIP Rendezvous Extensions IPSECKEY RR [13] ). is reachable by an I1 (HIP Rendezvous Extensions IPSECKEY RR [14] ).
Thus, an attacker able to tamper with this RRs is able to redirect I1 Thus, an attacker able to tamper with this RRs is able to redirect I1
packets sent to the named peer to a chosen IP address, for DoS or packets sent to the named peer to a chosen IP address, for DoS or
MitM attacks. Note that this kind of attacks are not specific to HIP MitM attacks. Note that this kind of attacks are not specific to HIP
and exist independently to whether or not HIP and the HIPRVS RR are and exist independently to whether or not HIP and the HIPRVS RR are
used. Such an attacker might tamper with A and AAAA RRs as well. used. Such an attacker might tamper with A and AAAA RRs as well.
An attacker might obviously use these two attacks in conjunction: It An attacker might obviously use these two attacks in conjunction: It
will replace the responder's HI and RVS IP address by its owns in a will replace the responder's HI and RVS IP address by its owns in a
spoofed DNS packet sent to the initiator HI, then redirect all spoofed DNS packet sent to the initiator HI, then redirect all
exchanged packets through him and mount a MitM on HIP. In this case exchanged packets through him and mount a MitM on HIP. In this case
HIP won't provide confidentiality nor initiator HI protection from HIP won't provide confidentiality nor initiator HI protection from
eavesdroppers. eavesdroppers.
9.3 Opportunistic HIP 8.3 Opportunistic HIP
A HIP initiator may not be aware of its peer's HI, and/or its HIT A HIP initiator may not be aware of its peer's HI, and/or its HIT
(e.g., because the DNS does not contains HIP material, or the (e.g. because the DNS does not contains HIP material, or the resolver
resolver isn't HIP-enabled), and attempt an opportunistic HIP isn't HIP-enabled), and attempt an opportunistic HIP exchange towards
exchange towards its known IP address, filling the responder HIT its known IP address, filling the responder HIT field with zeros in
field with zeros in the I1 header. Such an initiator is vulnerable the I1 header. Such an initiator is vulnerable to a MitM attack
to a MitM attack because it can't validate the HI and HIT contained because it can't validate the HI and HIT contained in a replied R1.
in a replied R1. Hence, an implementation MAY choose not to use Hence, an implementation MAY choose not to use opportunistic mode.
opportunistic mode.
9.4 Unpublished Initiator HI 8.4 Unpublished Initiator HI
A HIP initiator may choose to use an unpublished HI, which is not A HIP initiator may choose to use an unpublished HI, which is not
stored in the DNS by means of a HIPHI RR. A responder associating stored in the DNS by means of a HIPHI RR. A responder associating
with such an initiator knowingly risks a MitM attack because it with such an initiator knowingly risks a MitM attack because it
cannot validate the initiator's HI. Hence, an implementation MAY cannot validate the initiator's HI. Hence, an implementation MAY
choose not to use unpublished mode. choose not to use unpublished mode.
9.5 Hash and HITs Collisions 8.5 Hash and HITs Collisions
As many cryptographic algorithm, some secure hashes (e.g. SHA1, used As many cryptographic algorithm, some secure hashes (e.g. SHA1, used
by HIP to generate a HIT from an HI) eventually become insecure, by HIP to generate a HIT from an HI) eventually become insecure,
because an exploit has been found in which an attacker with a because an exploit has been found in which an attacker with a
reasonable computation power breaks one of the security features of reasonable computation power breaks one of the security features of
the hash (e.g., its supposed collision resistance). This is why a the hash (e.g. its supposed collision resistance). This is why a HIP
HIP end-node implementation SHOULD NOT authenticate its HIP peers end-node implementation SHOULD NOT authenticate its HIP peers based
based solely on a HIT retrieved from DNS, but SHOULD rather use solely on a HIT retrieved from DNS, but SHOULD rather use HI-based
HI-based authentication. authentication.
10. IANA Considerations 8.6 DNSSEC
In the absence of DNSSEC, the HIPHI and HIPRVS RRs are subject to the
threats described in RFC 3833 [17].
9. IANA Considerations
IANA needs to allocate two new RR type code for HIPHI and HIPRVS from IANA needs to allocate two new RR type code for HIPHI and HIPRVS from
the standard RR type space. the standard RR type space.
IANA needs to open a new registry for the HIPHI RR HIT type. Defined IANA needs to open a new registry for the HIPHI RR HIT type. Defined
types are: types are:
0 No HIT is present 0 No HIT is present
1 A Type 1 HIT is present 1 A Type 1 HIT is present
2 A Type 2 HIT is present 2 A Type 2 HIT is present
3-6 Unassigned 3-6 Unassigned
7 A HAA is present 7 A HAA is present
Adding new reservations requires IETF consensus RFC2434 [16]. Adding new reservations requires IETF consensus RFC2434 [16].
IANA needs to open a new registry for the HIPHI RR HIT algorithm. IANA needs to open a new registry for the HIPHI RR HIT algorithm.
Defined types are: Defined types are:
0 Reserved 0 Reserved
1 SHA1 1 SHA1
2-255 Unassigned 2-255 Unassigned
Adding new reservations requires IETF consensus RFC2434 [16]. Adding new reservations requires IETF consensus RFC2434 [16].
IANA does not need to open a new registry for the HIPHI RR type for IANA does not need to open a new registry for the HIPHI RR type for
public key algorithms because the HIPHI RR reuse 'algorithms types' public key algorithms because the HIPHI RR reuse 'algorithms types'
defined for the IPSECKEY RR [14]. The presently defined numbers are defined for the IPSECKEY RR [10]. The presently defined numbers are
given here only informally: given here only informally:
0 is reserved 0 is reserved
1 is RSA 1 is RSA
2 is DSA 2 is DSA
IANA does not need to open a new registry for the HIPRVS RR IANA does not need to open a new registry for the HIPRVS RR
Rendezvous server type because the HIPHI RR reuse the 'gateway types' Rendezvous server type because the HIPHI RR reuse the 'gateway types'
defined for the IPSECKEY RR [14]. The presently defined numbers are defined for the IPSECKEY RR [10]. The presently defined numbers are
given here only informally: given here only informally:
0 is reserved 0 is reserved
1 is IPv4 1 is IPv4
2 is IPv6 2 is IPv6
3 is a wire-encoded uncompressed domain name 3 is a wire-encoded uncompressed domain name
11. Acknowledgments 10. Acknowledgments
As usual in the IETF, this document is the result of a collaboration As usual in the IETF, this document is the result of a collaboration
between many people. The authors would like to thanks the author between many people. The authors would like to thanks the author
(Michael Richardson), contributors and reviewers of the IPSECKEY RR (Michael Richardson), contributors and reviewers of the IPSECKEY RR
[14] specification, which this document was framed after. The [10] specification, which this document was framed after. The
authors would also like to thanks the following people, who have authors would also like to thanks the following people, who have
provided thoughtful and helpful discussions and/or suggestions, that provided thoughtful and helpful discussions and/or suggestions, that
have helped improving this document: Rob Austein, Hannu Flinck, Tom have helped improving this document: Rob Austein, Hannu Flinck, Tom
Henderson, Miika Komu, Andrew McGregor, Erik Nordmark, and Gabriel Henderson, Olaf Kolkman, Miika Komu, Andrew McGregor, Erik Nordmark,
Montenegro. Some parts of this draft stem from [10]. and Gabriel Montenegro. Some parts of this draft stem from [11].
12. References Julien Laganier is partly funded by Ambient Networks, a research
project supported by the European Commission under its Sixth
Framework Program. The views and conclusions contained herein are
those of the authors and should not be interpreted as necessarily
representing the official policies or endorsements, either expressed
or implied, of the Ambient Networks project or the European
Commission.
12.1 Normative references 11. References
[1] Mockapetris, P., "Domain names - concepts and facilities", STD 11.1 Normative references
13, RFC 1034, November 1987.
[1] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[2] Mockapetris, P., "Domain names - implementation and [2] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
[3] Eastlake, D. and C. Kaufman, "Domain Name System Security [3] Eastlake, D. and C. Kaufman, "Domain Name System Security
Extensions", RFC 2065, January 1997. Extensions", RFC 2065, January 1997.
[4] Bradner, S., "Key words for use in RFCs to Indicate Requirement [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[5] Eastlake, D., "DSA KEYs and SIGs in the Domain Name System [5] Eastlake, D., "DSA KEYs and SIGs in the Domain Name System
(DNS)", RFC 2536, March 1999. (DNS)", RFC 2536, March 1999.
[6] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name [6] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain Name
System (DNS)", RFC 3110, May 2001. System (DNS)", RFC 3110, May 2001.
[7] Bush, R., Durand, A., Fink, B., Gudmundsson, O. and T. Hain, [7] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. Hain,
"Representing Internet Protocol version 6 (IPv6) Addresses in "Representing Internet Protocol version 6 (IPv6) Addresses in
the Domain Name System (DNS)", RFC 3363, August 2002. the Domain Name System (DNS)", RFC 3363, August 2002.
[8] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", [8] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings",
RFC 3548, July 2003. RFC 3548, July 2003.
[9] Thomson, S., Huitema, C., Ksinant, V. and M. Souissi, "DNS [9] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, "DNS
Extensions to Support IP Version 6", RFC 3596, October 2003. Extensions to Support IP Version 6", RFC 3596, October 2003.
[10] Moskowitz, R., Nikander, P. and P. Jokela, "Host Identity [10] Richardson, M., "A Method for Storing IPsec Keying Material in
Protocol", draft-ietf-hip-base-01 (work in progress), October DNS", RFC 4025, March 2005.
2004.
[11] Moskowitz, R. and P. Nikander, "Host Identity Protocol [11] Moskowitz, R., "Host Identity Protocol", draft-ietf-hip-base-03
Architecture", draft-ietf-hip-arch-00 (work in progress), (work in progress), June 2005.
October 2004.
[12] Nikander, P., "End-Host Mobility and Multi-Homing with Host [12] Moskowitz, R., "Host Identity Protocol Architecture",
Identity Protocol", draft-ietf-hip-mm-00 (work in progress), draft-ietf-hip-arch-02 (work in progress), January 2005.
October 2004.
[13] Laganier, J. and L. Eggert, "Host Identity Protocol (HIP) [13] Nikander, P., "End-Host Mobility and Multi-Homing with Host
Rendezvous Extensions", draft-ietf-hip-rvs-00 (work in Identity Protocol", draft-ietf-hip-mm-01 (work in progress),
progress), October 2004. February 2005.
[14] Richardson, M., "A method for storing IPsec keying material in [14] Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)
DNS", draft-ietf-ipseckey-rr-12 (work in progress), January Rendezvous Extension", draft-ietf-hip-rvs-02 (work in
2005. progress), June 2005.
12.2 Informative references 11.2 Informative references
[15] Jokela, P., Moskowitz, R. and P. Nikander, "Using ESP transport [15] Jokela, P., "Using ESP transport format with HIP",
format with HIP", draft-jokela-hip-esp-00 (work in progress), draft-jokela-hip-esp-00 (work in progress), February 2005.
February 2005.
[16] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [16] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October Considerations Section in RFCs", BCP 26, RFC 2434,
1998. October 1998.
[17] Atkins, D. and R. Austein, "Threat Analysis of the Domain Name
System (DNS)", RFC 3833, August 2004.
Authors' Addresses Authors' Addresses
Pekka Nikander Pekka Nikander
Ericsson Research Nomadic Lab Ericsson Research Nomadic Lab
JORVAS FIN-02420 JORVAS FIN-02420
FINLAND FINLAND
Phone: +358 9 299 1 Phone: +358 9 299 1
EMail: pekka.nikander@nomadiclab.com Email: pekka.nikander@nomadiclab.com
Julien Laganier Julien Laganier
LIP (CNRS-INRIA-ENSL-UCBL) & Sun Labs (Sun Microsystems) DoCoMo Communications Laboratories Europe GmbH
180, Avenue de l'Europe Landsberger Strasse 312
Saint Ismier CEDEX 38334 Munich 80687
France Germany
Phone: +33 476 188 815
EMail: ju@sun.com
Appendix A. Document Revision History
+-----------+-------------------------------------------------------+ Phone: +49 89 56824 231
| Revision | Comments | Email: julien.ietf@laposte.net
+-----------+-------------------------------------------------------+ URI: http://www.docomolab-euro.com/
| 01 | Compared to draft-ietf-hip-dns-01: Removed HIP |
| | rendezvous registration protocol. Removed references |
| | to DNS. Added figures. Added text discussing multiple |
| | HITs and IP. |
| | |
| 00 | Initial version as a HIP WG item. |
+-----------+-------------------------------------------------------+
Intellectual Property Statement Intellectual Property Statement
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made any independent effort to identify any such rights. Information made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
 End of changes. 

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