draft-ietf-hip-dns-02.txt   draft-ietf-hip-dns-03.txt 
Network Working Group P. Nikander Network Working Group P. Nikander
Internet-Draft Ericsson Research Nomadic Lab Internet-Draft Ericsson Research Nomadic Lab
Expires: January 14, 2006 J. Laganier Expires: April 13, 2006 J. Laganier
DoCoMo Euro-Labs DoCoMo Euro-Labs
July 11, 2005 October 10, 2005
Host Identity Protocol (HIP) Domain Name System (DNS) Extensions Host Identity Protocol (HIP) Domain Name System (DNS) Extensions
draft-ietf-hip-dns-02 draft-ietf-hip-dns-03
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 1, line 35 skipping to change at page 1, line 35
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 14, 2006. This Internet-Draft will expire on April 13, 2006.
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 . . . . . . . . . . . . . . 6 2. Conventions used in this document . . . . . . . . . . . . . . 6
3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 7 3. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Simple static singly homed end-host . . . . . . . . . . . 8 3.1. Simple static singly homed end-host . . . . . . . . . . . 8
3.2 Mobile end-host . . . . . . . . . . . . . . . . . . . . . 9 3.2. Mobile end-host . . . . . . . . . . . . . . . . . . . . . 9
3.3 Mixed Scenario . . . . . . . . . . . . . . . . . . . . . . 10 3.3. Mixed Scenario . . . . . . . . . . . . . . . . . . . . . . 10
4. Overview of using the DNS with HIP . . . . . . . . . . . . . . 12 4. Overview of using the DNS with HIP . . . . . . . . . . . . . . 12
4.1 Storing HI and HIT in DNS . . . . . . . . . . . . . . . . 12 4.1. Storing HI and HIT in DNS . . . . . . . . . . . . . . . . 12
4.1.1 Different types of HITs . . . . . . . . . . . . . . . 12 4.1.1. HI and HIT Verification . . . . . . . . . . . . . . . 12
4.2 Storing Rendezvous Servers in the DNS . . . . . . . . . . 13 4.2. Storing Rendezvous Servers in the DNS . . . . . . . . . . 12
4.3 Initiating connections based on DNS names . . . . . . . . 13 4.3. Initiating connections based on DNS names . . . . . . . . 12
5. Storage Format . . . . . . . . . . . . . . . . . . . . . . . . 14 5. Storage Format . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1 HIPHI RDATA format . . . . . . . . . . . . . . . . . . . . 14 5.1. HIPHI RDATA format . . . . . . . . . . . . . . . . . . . . 13
5.1.1 HIT type format . . . . . . . . . . . . . . . . . . . 14 5.1.1. PK algorithm format . . . . . . . . . . . . . . . . . 13
5.1.2 HIT algorithm format . . . . . . . . . . . . . . . . . 14 5.1.2. HIT length format . . . . . . . . . . . . . . . . . . 13
5.1.3 PK algorithm format . . . . . . . . . . . . . . . . . 15 5.1.3. HIT format . . . . . . . . . . . . . . . . . . . . . . 13
5.1.4 HIT format . . . . . . . . . . . . . . . . . . . . . . 15 5.1.4. Public key format . . . . . . . . . . . . . . . . . . 13
5.1.5 Public key format . . . . . . . . . . . . . . . . . . 15 5.2. HIPRVS RDATA format . . . . . . . . . . . . . . . . . . . 14
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 . . . . . . . . . . . . . . . 15
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 . . . . . . . . . . . . . . . . . . . . . . . . . 16
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. Security Considerations . . . . . . . . . . . . . . . . . . . 19
8. Security Considerations . . . . . . . . . . . . . . . . . . . 21 8.1. Attacker tampering with an insecure HIPHI RR . . . . . . . 19
8.1 Attacker tampering with an unsecure HIPHI RR . . . . . . . 21 8.2. Attacker tampering with an insecure HIPRVS RR . . . . . . 19
8.2 Attacker tampering with an unsecure HIPRVS RR . . . . . . 21 8.3. Opportunistic HIP . . . . . . . . . . . . . . . . . . . . 20
8.3 Opportunistic HIP . . . . . . . . . . . . . . . . . . . . 22 8.4. Unpublished Initiator HI . . . . . . . . . . . . . . . . . 20
8.4 Unpublished Initiator HI . . . . . . . . . . . . . . . . . 22 8.5. Hash and HITs Collisions . . . . . . . . . . . . . . . . . 20
8.5 Hash and HITs Collisions . . . . . . . . . . . . . . . . . 22 8.6. DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.6 DNSSEC . . . . . . . . . . . . . . . . . . . . . . . . . . 22 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . 25 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 11.1. Normative references . . . . . . . . . . . . . . . . . . . 23
11.1 Normative references . . . . . . . . . . . . . . . . . . . 26 11.2. Informative references . . . . . . . . . . . . . . . . . . 24
11.2 Informative references . . . . . . . . . . . . . . . . . . 27 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 27 Intellectual Property and Copyright Statements . . . . . . . . . . 26
Intellectual Property and Copyright Statements . . . . . . . . 28
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) [RFC1034], and how to use them with the Host
Protocol (HIP) [11]. These RRs allow a HIP node to store in the DNS Identity Protocol (HIP) [I-D.ietf-hip-base]. These RRs allow a HIP
its Host Identity (HI, the public component of the node public- node to store in the DNS its Host Identity (HI, the public component
private key pair), Host Identity Tag (HIT, a truncated hash of its of the node public-private key pair), Host Identity Tag (HIT, a
HI), and the Domain Name or IP addresses of its Rendezvous Servers truncated hash of its HI), and the Domain Name or IP addresses of its
(RVS) [14]. rendezvous servers (RVS) [I-D.ietf-hip-rvs].
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 [12] way lookup between these two namespaces. The HIP architecture
defines a new third namespace, called the Host Identity Namespace. [I-D.ietf-hip-arch] defines a new third namespace, called the Host
This namespace is composed of Host Identifiers (HI) of HIP nodes. Identity Namespace. This namespace is composed of Host Identifiers
The Host Identity Tag (HIT) is one representation of an HI. This (HI) of HIP nodes. The Host Identity Tag (HIT) is one representation
representation is obtained by taking the output of a secure hash of an HI. This representation is obtained by taking the output of a
function applied to the HI, truncated to the IPv6 address size. HITs secure hash function applied to the HI, truncated to the IPv6 address
are supposed to be used in the place of IP addresses within most ULPs size. HITs are supposed to be used in the place of IP addresses
and applications. within most ULPs and applications.
The Host Identity Protocol [11] allows two HIP nodes to establish The Host Identity Protocol [I-D.ietf-hip-base] allows two HIP nodes
together a HIP Association. A HIP association is bound to the nodes to establish together a HIP Association. A HIP association is bound
HIs rather than to their IP address(es). to the nodes HIs rather than to their IP address(es).
A HIP node establish a HIP association by initiating a 4 way A HIP node establish a HIP association by initiating a 4 way
handshake where two parties, the Initiatior and Responder, exchange handshake where two parties, the initiator and responder, exchange
the I1, I2, R1 and R2 HIP packets (see section 5.3 of [11]) the I1, I2, R1 and R2 HIP packets (see section 5.3 of [I-D.ietf-hip-
base])
+-----+ +-----+ +-----+ +-----+
| |-------I1------>| | | |-------I1------>| |
| I |<------R1-------| R | | I |<------R1-------| R |
| |-------I2------>| | | |-------I2------>| |
| |<------R2-------| | | |<------R2-------| |
+-----+ +-----+ +-----+ +-----+
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 prior knowledge of its peer's HI,
HI, doing so exposes both endpoints to Man-in-the-Middle attacks on doing so exposes both endpoints to Man-in-the-Middle attacks on the
the HIP handshake and its cryptographic protocol. Hence, there is a 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, DNS is a straightforward way to Name System [RFC1034] 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 information (i.e. HI, HIT and possibly
of nodes named in the DNS tree, without introducing or relying on an RVS) of nodes named in the DNS tree, without introducing or relying
additional piece of infrastructure. Note that without DNSSEC [3] the on an additional piece of infrastructure. Note that in the absence
Man-in-the-Middle attack evocated before has moved from the of DNSSEC [RFC2065], the DNS name resolution is vulnerable to Man-in-
opportunistic HIP handshake to the DNS name resolution; See also the-Middle attack (See Section 8), and hence the HIP handshake is
Section 8. also vulnerable to a Man-in-the-Middle attack.
The proposed HIP multi-homing mechanisms [13] allow a node to The proposed HIP multi-homing mechanisms [I-D.ietf-hip-mm] allow a
dynamically change its set of underlying IP addresses while node to dynamically change its set of underlying IP addresses while
maintaining IPsec SA and transport layer session survivability. The maintaining IPsec SA and transport layer session survivability. The
HIP rendezvous extensions [14] proposal allows a HIP node to maintain HIP rendezvous extensions [I-D.ietf-hip-rvs] proposal allows a HIP
HIP reachability while it is changing its current location (the node node to maintain HIP reachability while it is changing its current
IP address(es)). This rendezvous service is provided by a third location (the node IP address(es)). This rendezvous service is
party, the node's Rendezvous Server (RVS). 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-------| |
+-----+ +-----+ +-----+ +-----+
An initiator (I) willing to establish a HIP association with a An initiator (I) willing to establish a HIP association with a
responder (R) would typically initiate a HIP exchange by sending an responder (R) would typically initiate a HIP exchange by sending an
I1 towards the RVS IP address rather than towards the responder IP I1 towards the RVS IP address rather than towards the responder IP
address. Then, the RVS, noticing that the receiver HIT is not its 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, own, but the HIT of a HIP node registered for the rendezvous service,
would relay the I1 to the responder. Typically the responder would would relay the I1 to the responder. Typically the responder would
then complete the exchange without further assistance from the RVS by then complete the exchange without further assistance from the RVS by
sending an R1 directly to the initiator IP address. 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 use
uses HIs or HITs instead (ICMP might be an example of an ULP not HIs or HITs instead (ICMP might be an example of an ULP not using
using them). Consequently, we need a means to translate a domain them). Consequently, we need a means to translate a domain name into
name into an HI. Using the DNS for this translation is pretty an HI. Using the DNS for this translation is pretty straightforward:
straightforward: We define a new HIPHI (HIP HI) resource record. We define a new HIPHI (HIP HI) resource record. Upon query by an
Upon query by an application or ULP for a FQDN -> IP lookup, the application or ULP for a FQDN -> IP lookup, the resolver would then
resolver would then additionally perform an FQDN -> HI lookup, and additionally perform an FQDN -> HI lookup, and use it to construct
use it to construct the resulting HI -> IP mapping (which is internal the resulting HI -> IP mapping (which is internal to the HIP layer).
to the HIP layer). The HIP layer uses the HI -> IP mapping to The HIP layer uses the HI -> IP mapping to translate HIs and their
translate HIs and their local representations (HITs, IPv4 and IPv6- local representations (HITs, IPv4 and IPv6-compatible LSIs) into IP
compatible LSIs) into IP addresses and vice versa. 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 [RFC2119].
3. Usage Scenarios 3. Usage Scenarios
In this section, we briefly introduce a number of usage scenarios In this section, we briefly introduce a number of usage scenarios
where the DNS is useful with the Host Identity Protocol. where the DNS is useful with the Host Identity Protocol.
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 information in the DNS:
o A set of IP address(es) through A and AAAA RRs. o A set of IP address(es) through A and AAAA RRs.
o A Host Identity (HI) and/or Host Identity Tag (HIT) through HIPHI o A Host Identity (HI) and/or Host Identity Tag (HIT) through HIPHI
RRs. RRs.
o An IP address or DNS name of its Rendezvous Server(s) (RVS) o An IP address or DNS name of its rendezvous server(s) (RVS)
through HIPRVS RRs. 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 prior knowledge of the
responder's HI, by doing so both nodes knowingly risk man-in-the- responder's HI, by doing so both nodes knowingly risk man-in-the-
middle attacks on the HIP exchange. To prevent these attacks, it is middle attacks on the HIP exchange. To prevent these attacks, it is
recommended that the initiator first obtain the HI of the responder, recommended that the initiator first obtain the HI of the responder,
and then initiate the exchange. This can be done, for example, and then initiate the exchange. This can be done, for example,
through manual configuration or DNS lookups. Hence, a new HIPHI RR through manual configuration or DNS lookups. Hence, a new 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.
When a HIP node wants to initiate a HIP exchange with a responder it When a HIP node wants to initiate a HIP exchange with a responder it
will perform a number of DNS lookups. First the initiator will need will perform a number of DNS lookups. Depending on the type of the
to query for an A or AAAA record at the responders FQDN. implementation, the order in which those lookups will be issued may
vary. For instance, implementations using IP address in APIs may
typically first query for A and/or AAAA records at the responder
FQDN, while those using HIT in APIS may typically first query for
HIPHI records.
In the following we assume that the initiator first queries for A
and/or AAAA records at the responder FQDN.
If the query for the A and/or AAAA was responded to with a DNS answer 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 with RCODE=3 (Name Error), then the responder's information is not
present in the DNS and further queries SHOULD NOT be made. present in the DNS and further queries SHOULD NOT be made.
In case the query for the address records returned a DNS answer with 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 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. the HIPHI type and one for the HIPRVS type at the responder's FQDN.
Depending on the combinations of answer the situations described in Depending on the combinations of answer the situations described in
Section 3.1, Section 3.2 and Section 3.3 can occur. 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 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 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 the DNS, in addition to its IP address(es) (IP-R), its Host Identity
(HI-R) in a HIPHI resource record. (HI-R) in a HIPHI resource record.
An initiator willing to associate with a node would typically issue An initiator willing to associate with a node would typically issue
the following queries: the following queries:
QNAME=www.example.com, QTYPE=A QNAME=www.example.com, QTYPE=A
(QCLASS=IN is assumed and ommitted from the examples) (QCLASS=IN is assumed and omitted from the examples)
Which returns a DNS packet with RCODE=0 and one or more A RRs A with 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. the address of the responder (e.g. IP-R) in the answer section.
QNAME=www.example.com, QTYPE=HIPHI QNAME=www.example.com, QTYPE=HIPHI
Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs 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 with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the
answer section. answer section.
skipping to change at page 9, line 28 skipping to change at page 9, line 28
| | [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--------------| |
+-----+ +-----+ +-----+ +-----+
3.2 Mobile end-host 3.2. Mobile end-host
A mobile HIP node (R) wishing to be reachable by reference to its 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 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 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 address(es) of its rendezvous server(s) (IP-RVS) in HIPRVS resource
record(s). The mobile HIP node also need to notify its Rendezvous record(s). The mobile HIP node also needs to notify its rendezvous
Servers of any change in its set of IP address(es). servers of any change in its set of IP address(es).
An initiator willing to associate with such mobile node would An initiator willing to associate with such mobile node would
typically issue the following queries: typically issue the following queries:
QNAME=www.example.com, QTYPE=A QNAME=www.example.com, QTYPE=A
Which returns a DNS packet with RCODE=0 and an empty answer section. Which returns a DNS packet with RCODE=0 and an empty answer section.
QNAME=www.example.com, QTYPE=HIPHI QNAME=www.example.com, QTYPE=HIPHI
Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs 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 with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the
answer section. answer section.
QNAME=www.example.com, QTYPE=HIPRVS QNAME=www.example.com, QTYPE=HIPRVS
Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs 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). 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 10, line 36 skipping to change at page 10, line 33
+-----+ +-----+ +-----+ +-----+
| |<---------------R1------------| | | |<---------------R1------------| |
| I |----------------I2----------->| R | | I |----------------I2----------->| R |
| |<---------------R2------------| | | |<---------------R2------------| |
+-----+ +-----+ +-----+ +-----+
The initiator would then send an I1 to one of its RVS. Following, The initiator 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 RVS will relay the I1 up to the mobile node, which will complete
the HIP exchange. the HIP exchange.
3.3 Mixed Scenario 3.3. Mixed Scenario
A HIP node might be configured with more than one IP address (multi- A HIP node might be configured with more than one IP address (multi-
homed), or Rendezvous Server (multi-reachable). In these cases, it homed), or rendezvous server (multi-reachable). In these cases, it
is possible that the DNS returns multiple A or AAAA RRs, as well as is possible that the DNS returns multiple A or AAAA RRs, as well as
HIPRVS containing one or multiple Rendezvous Servers. In addition to 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 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 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. 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 An initiator willing to associate with such a node would typically
issue the following queries: issue the following queries:
QNAME=www.example.com, QTYPE=A QNAME=www.example.com, QTYPE=A
Which returns a DNS packet with RCODE=0 and one or more A or AAAA RRs 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 containing IP address(es) (e.g. IP-R1 and IP-R2) in the answer
section. section.
QNAME=www.example.com, QTYPE=HIPHI QNAME=www.example.com, QTYPE=HIPHI
Which returns a DNS packet with RCODE=0 and one or more HIPHI RRs 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 with the HIT and HI (e.g. HIT-R and HI-R) of the responder in the
answer section. answer section.
QNAME=www.example.com, QTYPE=HIPRVS QNAME=www.example.com, QTYPE=HIPRVS
Which returns a DNS packet with RCODE=0 and one or more HIPRVS RRs 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 containing IP address(es) (e.g. IP-RVS1, IP-RVS2) or FQDN(s) of
RVS(s). 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 ]
skipping to change at page 12, line 7 skipping to change at page 12, line 7
| |---------------I2------------->| | | |---------------I2------------->| |
| |<--------------R2--------------| | | |<--------------R2--------------| |
+-----+ +-----+ +-----+ +-----+
| ^ | ^
| +------+ | | +------+ |
+-----I1----->| RVS2 |------I1------+ +-----I1----->| RVS2 |------I1------+
+------+ +------+
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
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
not already have a specified RDATA format, a new RDATA-like format
SHOULD be defined for the HI or HIT.
4.1.1 Different types of HITs
There are two types of HITs. HITs of the first type, called Type 1
HIT, consist of an 8-bit prefix followed by 120 bits of the hash of
the public key. HITs of the second type (Type 2 HIT) consist of a
Host Assigning Authority Field (HAA), and only the last 64 bits come
from a SHA-1 hash of the Host Identity. This latter format for HIT
is recommended for 'well known' systems. It is possible to support a
resolution mechanism for these names in hierarchical directories,
like the DNS.
This document fully specifies only Type 2 HITs. Type 1 HITs are
specified in Section 3.1 of [11].
Note that the format how HITs are stored in the HIPHI RRs may be
different form the format actually used in protocols, the HIP base
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
The 64 bits of HAA supports two levels of delegation. The first is a
registered assigning authority (RAA). The second is a registered
identity (RI, commonly a company). The RAA is 24 bits with values
assign sequentially by ICANN. The RI is 40 bits, also assigned
sequentially but by the RAA.
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 Host Identity (HI) and its
Authority (HAA) in a DNS HIPHI RDATA format. A HAA MUST be stored associated Host Identity Tag (HIT) in a DNS HIPHI RDATA format. If a
like a Type 2 HIT, while the least significant bits of the HIT particular form of an HI does not already have a specified RDATA
extracted from the HI hash output are set to zero, the Host Identity format, a new RDATA-like format SHOULD be defined for the HI. HI and
Length is set zero, and the Host Identity field is omitted. If a HIT are defined in Section 3 of [I-D.ietf-hip-base].
particular form of a HAA does not already have an associated HIT
specified RDATA format, a new RDATA-like format SHOULD be defined for
the HIT/HAA.
4.1.1.3 HI and HIT verification 4.1.1. HI and HIT Verification
Upon return of a HIPHI RR, a host MUST always calculate the HI- Upon return of a HIPHI RR, a host MUST always calculate the 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
HIP architecture [12], while the HIT possibly embedded along SHOULD Section 3 of the HIP base specification [I-D.ietf-hip-base], while
only be used as an optimization (e.g. table lookup). the HIT possibly embedded along SHOULD 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 [14]. association with the entity named by this resource record [I-D.ietf-
hip-rvs].
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 [11]. Since some hosts may choose not to towards one of these RVS [I-D.ietf-hip-base]. Since some hosts may
have HIPHI information in DNS, hosts MAY implement support for choose not to have HIPHI information in DNS, hosts MAY implement
opportunistic HIP. support for 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 public key algorithm type, the
HIT, and a public key. HIT length, a HIT, and a public key.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HIT type | HIT algorithm | PK algorithm | | | PK algorithm | HIT length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ HIT | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ HIT |
~ ~ ~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| / | /
/ Public Key / / Public Key /
/ / / /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-|
5.1.1 HIT type format The PK algorithm, HIT length, HIT and Public Key field are REQUIRED.
The HIT type field indicates the Host Identity Tag (HIT) type and the
implied HIT format.
The following values are defined:
0 No HIT is present
1 A Type 1 HIT is present
2 A Type 2 HIT is present
3-6 Unassigned
7 A HAA is present
5.1.2 HIT algorithm format
The HIT algorithm indicates the hash algorithm used to generate the
Host Identity Tag (HIT) from the HI.
The following values are defined:
0 Reserved
1 SHA1
2-255 Unassigned
5.1.3 PK algorithm format 5.1.1. 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
[10] 'gateway type' field. [RFC4025] '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
[RFC2536].
2 A RSA key is present, in the format defined in RFC3110 [6].
5.1.4 HIT format 2 A RSA key is present, in the format defined in RFC3110
[RFC3110].
There's currently two types of HITs, and a single type of HAA. Both 5.1.2. HIT length format
of them are stored in network byte order within a self-describing
variable length wire-encoded <character-string> (as per Section 3.3
of [2]):
o A *Type 1* HIT: least significant bits of the hash (e.g. SHA1) of The HIT length indicates the length in bytes of the HIT field.
the public key (Host Identity), which is possibly following in the
HIPHI RR.
o A *Type 2* HIT: binary prefix (HAA) concatenated with a the least 5.1.3. HIT format
significant bits of the hash (e.g. SHA1) of the public key (Host
Identity), which is possibly following in the HIPHI RR.
o A HAA: binary prefix (HAA) concatenated with 0, up to the The HIT is stored, as a binary value, in network byte order.
associated HIT length.
5.1.5 Public key format 5.1.4. 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 [10] (which reuse the public key formats defined for the IPSECKEY RR [RFC4025]
in turns contains the algorithm-specific portion of the KEY RR RDATA, (which in turns contains the algorithm-specific portion of the KEY RR
all of the KEY RR DATA after the first four octets, corresponding to RDATA, all of the KEY RR DATA after the first four octets,
the same portion of the KEY RR that must be specified by documents corresponding to the same portion of the KEY RR that must be
that define a DNSSEC algorithm). specified by documents 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 encoding 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 [RFC2536].
The RSA key format is defined in RFC3110 [6] and the RSA key size The RSA key format is defined in RFC3110 [RFC3110] and the RSA key
limit (4096 bits) is relaxed in the IPSECKEY RR [10] specification. size limit (4096 bits) is relaxed in the IPSECKEY RR [RFC4025]
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 The Preference and RVS Type fields are REQUIRED. At least one RVS
field MUST be present.
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 the RVS in the HIPRVS RR amongst others at the same owner. RVSs to the RVS in the HIPRVS RR amongst others at the same owner. RVSs
with lower values are preferred. If there is a tie within some RR with lower values are preferred. If there is a tie within some RR
subset, the initiating HIP host should pick one of the RVS randomly subset, the initiating HIP host should pick one of the RVS randomly
from the set of RRs, such that the requester load is fairly balanced from the set of RRs, such that the requester load is fairly balanced
amongst all RVSs of 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 [10]. The presently defined values are given only the IPSECKEY RR [RFC4025]. The presently defined values are given
informally: only 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 [RFC1035]. The wire-encoded
is self-describing, so the length is implicit. The domain names format is self-describing, so the length is implicit. The domain
MUST NOT be compressed. names 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 [10], but allows to concatenate several IP (v4 or v6) IPSECKEY RR [RFC4025], but allows to concatenate several IP (v4 or
addresses. The presently defined formats for the data portion of the v6) addresses. The presently defined formats for the data portion of
Rendezvous server field are given only informally: the 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 self- in Section 3.3 of RFC1035 [RFC1035]. The wire-encoded format is
describing, so the length is implicit. The domain names MUST NOT self-describing, so the length is implicit. The domain names MUST
be compressed. NOT 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, HIT and Public Key are The PK algorithm field is represented as unsigned integers.
REQUIRED.
The HIT Type, HIT algorithm, and PK algorithm are represented as The HIT length field is not represented as it is implicitly known
unsigned integers. thanks to the HIT field representation.
The HIT field is represented as the Base16 encoding [8] (a.k.a. hex The HIT field is represented as the Base16 encoding [RFC3548] (a.k.a.
or hexadecimal) of the public key hash. The encoding MUST NOT hex or hexadecimal) of the HIT. The encoding MUST NOT contains
contains whitespace. If no HIT is to be indicated, then the HIT whitespace(s).
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 [RFC3548]
public key. The encoding MAY contains whitespace(s), and such of the public key. The encoding MAY contains whitespace(s), and such
whitespaces MUST be ignored. whitespace(s) 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 ( 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
field MUST be present.
The HIT Type, HIT algorithm, and PK algorithm are represented as
unsigned integers.
The RVS field is represented by one or more: The RVS field is represented by one or more:
o IPv4 dotted decimal address(es) o IPv4 dotted decimal address(es)
o IPv6 colon hex address(es) o IPv6 colon hex address(es)
o uncompressed domain name(s) o uncompressed domain name(s)
The complete representation of the HPIRVS record is: The complete representation of the HPIRVS record is:
IN HIPRVS ( preference rendezvous-server-type IN HIPRVS ( preference rendezvous-server-type
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:
www.example.com IN HIPHI ( 0 1 2
.
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 ( 2 2A20E0FF0FE8A52422D059FFFEA938A1
AB3NzaC1kc3MAAACBAOBhKn AB3NzaC1kc3MAAACBAOBhKn
TCPOuFBzZQX/N3O9dm9P9iv TCPOuFBzZQX/N3O9dm9P9iv
UIMoId== ) 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:db8:200:1:20c:f1ff:feb: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:
skipping to change at page 20, line 34 skipping to change at page 18, 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
[11]). [I-D.ietf-hip-base]).
8. 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 [10], the HIP DNS Extensions In a manner similar to the IPSECKEY RR [RFC4025], the HIP DNS
allows to provision two HIP nodes with the public keying material Extensions allows to provision two HIP nodes with the public keying
(HI) of their peer. These HIs will be subsequently used in a key material (HI) of their peer. These HIs will be subsequently used in
exchange between the peers. Hence, the HIP DNS Extensions introduce a key exchange between the peers. Hence, the HIP DNS Extensions
the same kind of threats that IPSECKEY does, plus threats caused by introduce the same kind of threats that IPSECKEY does, plus threats
the possibility given to a HIP node to initiate or accept a HIP caused by the possibility given to a HIP node to initiate or accept a
exchange using "Opportunistic" or "Unpublished Initiator HI" modes. HIP 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 [RFC2065] 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.
8.1 Attacker tampering with an unsecure HIPHI RR 8.1. Attacker tampering with an insecure 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).
8.2 Attacker tampering with an unsecure HIPRVS RR 8.2. Attacker tampering with an insecure 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 [14] ). is reachable by an I1 (HIP Rendezvous Extensions IPSECKEY RR
Thus, an attacker able to tamper with this RRs is able to redirect I1 [I-D.ietf-hip-rvs] ). Thus, an attacker able to tamper with this RR
packets sent to the named peer to a chosen IP address, for DoS or is able to redirect I1 packets sent to the named peer to a chosen IP
MitM attacks. Note that this kind of attacks are not specific to HIP address, for DoS or MitM attacks. Note that this kind of attacks is
and exist independently to whether or not HIP and the HIPRVS RR are not specific to HIP and exists independently to whether or not HIP
used. Such an attacker might tamper with A and AAAA RRs as well. and the HIPRVS RR are 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 to him and mount a MitM on HIP. In this case HIP
HIP won't provide confidentiality nor initiator HI protection from won't provide confidentiality nor initiator HI protection from
eavesdroppers. eavesdroppers.
8.3 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 resolver (e.g. because the DNS does not contains HIP material, or the resolver
isn't HIP-enabled), and attempt an opportunistic HIP exchange towards isn't HIP-enabled), and attempt an opportunistic HIP exchange towards
its known IP address, filling the responder HIT field with zeros in its known IP address, filling the responder HIT field with zeros in
the I1 header. Such an initiator is vulnerable to a MitM attack the I1 header. Such an initiator is vulnerable to a MitM attack
because it can't validate the HI and HIT contained in a replied R1. because it can't validate the HI and HIT contained in a replied R1.
Hence, an implementation MAY choose not to use opportunistic mode. Hence, an implementation MAY choose not to use opportunistic mode.
8.4 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.
8.5 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 HIP the hash (e.g. its supposed collision resistance). This is why a HIP
end-node implementation SHOULD NOT authenticate its HIP peers based end-node implementation SHOULD NOT authenticate its HIP peers based
solely on a HIT retrieved from DNS, but SHOULD rather use HI-based solely on a HIT retrieved from DNS, but SHOULD rather use HI-based
authentication. authentication.
8.6 DNSSEC 8.6. DNSSEC
In the absence of DNSSEC, the HIPHI and HIPRVS RRs are subject to the In the absence of DNSSEC, the HIPHI and HIPRVS RRs are subject to the
threats described in RFC 3833 [17]. threats described in RFC 3833 [RFC3833].
9. IANA Considerations 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
types are:
0 No HIT is present
1 A Type 1 HIT is present
2 A Type 2 HIT is present
3-6 Unassigned
7 A HAA is present
Adding new reservations requires IETF consensus RFC2434 [16].
IANA needs to open a new registry for the HIPHI RR HIT algorithm.
Defined types are:
0 Reserved
1 SHA1
2-255 Unassigned
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 [10]. The presently defined numbers are defined for the IPSECKEY RR [RFC4025]. The presently defined numbers
given here only informally: are 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 [10]. The presently defined numbers are defined for the IPSECKEY RR [RFC4025]. The presently defined numbers
given here only informally: are 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
10. 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
[10] specification, which this document was framed after. The [RFC4025] 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, Olaf Kolkman, Miika Komu, Andrew McGregor, Erik Nordmark, Henderson, Olaf Kolkman, Miika Komu, Andrew McGregor, Erik Nordmark,
and Gabriel Montenegro. Some parts of this draft stem from [11]. and Gabriel Montenegro. Some parts of this draft stem from
[I-D.ietf-hip-base].
Julien Laganier is partly funded by Ambient Networks, a research Julien Laganier is partly funded by Ambient Networks, a research
project supported by the European Commission under its Sixth project supported by the European Commission under its Sixth
Framework Program. The views and conclusions contained herein are Framework Program. The views and conclusions contained herein are
those of the authors and should not be interpreted as necessarily those of the authors and should not be interpreted as necessarily
representing the official policies or endorsements, either expressed representing the official policies or endorsements, either expressed
or implied, of the Ambient Networks project or the European or implied, of the Ambient Networks project or the European
Commission. Commission.
11. References 11. References
11.1 Normative references 11.1. Normative references
[1] Mockapetris, P., "Domain names - concepts and facilities", [RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987. STD 13, RFC 1034, November 1987.
[2] Mockapetris, P., "Domain names - implementation and [RFC1035] 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 [RFC2065] 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 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[5] Eastlake, D., "DSA KEYs and SIGs in the Domain Name System [RFC2536] 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 [RFC3110] Eastlake, D., "RSA/SHA-1 SIGs and RSA KEYs in the Domain
System (DNS)", RFC 3110, May 2001. Name System (DNS)", RFC 3110, May 2001.
[7] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T. Hain,
"Representing Internet Protocol version 6 (IPv6) Addresses in
the Domain Name System (DNS)", RFC 3363, August 2002.
[8] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", [RFC3363] Bush, R., Durand, A., Fink, B., Gudmundsson, O., and T.
RFC 3548, July 2003. Hain, "Representing Internet Protocol version 6 (IPv6)
Addresses in the Domain Name System (DNS)", RFC 3363,
August 2002.
[9] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi, "DNS [RFC3548] Josefsson, S., "The Base16, Base32, and Base64 Data
Extensions to Support IP Version 6", RFC 3596, October 2003. Encodings", RFC 3548, July 2003.
[10] Richardson, M., "A Method for Storing IPsec Keying Material in [RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
DNS", RFC 4025, March 2005. "DNS Extensions to Support IP Version 6", RFC 3596,
October 2003.
[11] Moskowitz, R., "Host Identity Protocol", draft-ietf-hip-base-03 [RFC4025] Richardson, M., "A Method for Storing IPsec Keying
(work in progress), June 2005. Material in DNS", RFC 4025, March 2005.
[12] Moskowitz, R., "Host Identity Protocol Architecture", [I-D.ietf-hip-base]
draft-ietf-hip-arch-02 (work in progress), January 2005. Moskowitz, R., "Host Identity Protocol",
draft-ietf-hip-base-03 (work in progress), June 2005.
[13] Nikander, P., "End-Host Mobility and Multi-Homing with Host [I-D.ietf-hip-rvs]
Identity Protocol", draft-ietf-hip-mm-01 (work in progress), Laganier, J. and L. Eggert, "Host Identity Protocol (HIP)
February 2005. Rendezvous Extension", draft-ietf-hip-rvs-04 (work in
progress), October 2005.
[14] Laganier, J. and L. Eggert, "Host Identity Protocol (HIP) 11.2. Informative references
Rendezvous Extension", draft-ietf-hip-rvs-02 (work in
progress), June 2005.
11.2 Informative references [I-D.ietf-hip-arch]
Moskowitz, R. and P. Nikander, "Host Identity Protocol
Architecture", draft-ietf-hip-arch-03 (work in progress),
August 2005.
[15] Jokela, P., "Using ESP transport format with HIP", [I-D.ietf-hip-mm]
draft-jokela-hip-esp-00 (work in progress), February 2005. Nikander, P., "End-Host Mobility and Multihoming with the
Host Identity Protocol", draft-ietf-hip-mm-02 (work in
progress), July 2005.
[16] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
Considerations Section in RFCs", BCP 26, RFC 2434, IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998. October 1998.
[17] Atkins, D. and R. Austein, "Threat Analysis of the Domain Name [RFC3833] Atkins, D. and R. Austein, "Threat Analysis of the Domain
System (DNS)", RFC 3833, August 2004. 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
 End of changes. 119 change blocks. 
379 lines changed or deleted 279 lines changed or added

This html diff was produced by rfcdiff 1.27, available from http://www.levkowetz.com/ietf/tools/rfcdiff/