Internet Engineering Task Force (IETF) E. Jankiewicz
Request for Comments: 6434 SRI International, Inc.
Obsoletes: 4294 J. Loughney
Category: Informational Nokia
ISSN: 2070-1721 T. Narten
December 2011 IPv6 Node Requirements
This document defines requirements for IPv6 nodes. It is expected
that IPv6 will be deployed in a wide range of devices and situations.
Specifying the requirements for IPv6 nodes allows IPv6 to function
well and interoperate in a large number of situations and
This document obsoletes RFC 4294.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
This document defines common functionality required from both IPv6
hosts and routers. Many IPv6 nodes will implement optional or
additional features, but this document collects and summarizes
requirements from other published Standards Track documents in one
This document tries to avoid discussion of protocol details and
references RFCs for this purpose. This document is intended to be an
applicability statement and to provide guidance as to which IPv6
specifications should be implemented in the general case and which
specifications may be of interest to specific deployment scenarios.
This document does not update any individual protocol document RFCs.
Although this document points to different specifications, it should
be noted that in many cases, the granularity of a particular
requirement will be smaller than a single specification, as many
specifications define multiple, independent pieces, some of which may
not be mandatory. In addition, most specifications define both
client and server behavior in the same specification, while many
implementations will be focused on only one of those roles.
This document defines a minimal level of requirement needed for a
device to provide useful internet service and considers a broad range
of device types and deployment scenarios. Because of the wide range
of deployment scenarios, the minimal requirements specified in this
document may not be sufficient for all deployment scenarios. It is
perfectly reasonable (and indeed expected) for other profiles to
define additional or stricter requirements appropriate for specific
usage and deployment environments. For example, this document does
not mandate that all clients support DHCP, but some deployment
scenarios may deem it appropriate to make such a requirement. For
example, government agencies in the USA have defined profiles for
specialized requirements for IPv6 in target environments (see [DODv6]
As it is not always possible for an implementer to know the exact
usage of IPv6 in a node, an overriding requirement for IPv6 nodes is
that they should adhere to Jon Postel's Robustness Principle: "Be
conservative in what you do, be liberal in what you accept from
1.1. Scope of This Document
IPv6 covers many specifications. It is intended that IPv6 will be
deployed in many different situations and environments. Therefore,
it is important to develop requirements for IPv6 nodes to ensure
This document assumes that all IPv6 nodes meet the minimum
requirements specified here.
1.2. Description of IPv6 Nodes
From the Internet Protocol, Version 6 (IPv6) Specification [RFC2460],
we have the following definitions:
IPv6 node - a device that implements IPv6.
IPv6 router - a node that forwards IPv6 packets not explicitly
addressed to itself.
IPv6 host - any node that is not a router.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
3. Abbreviations Used in This Document
ATM Asynchronous Transfer Mode
AH Authentication Header
DAD Duplicate Address Detection
ESP Encapsulating Security Payload
ICMP Internet Control Message Protocol
IKE Internet Key Exchange
MIB Management Information Base
MLD Multicast Listener Discovery
MTU Maximum Transmission Unit
NA Neighbor Advertisement
NBMA Non-Broadcast Multiple Access
ND Neighbor Discovery
NS Neighbor Solicitation
NUD Neighbor Unreachability Detection
PPP Point-to-Point Protocol
4. Sub-IP Layer
An IPv6 node must include support for one or more IPv6 link-layer
specifications. Which link-layer specifications an implementation
should include will depend upon what link-layers are supported by the
hardware available on the system. It is possible for a conformant
IPv6 node to support IPv6 on some of its interfaces and not on
As IPv6 is run over new layer 2 technologies, it is expected that new
specifications will be issued. In the following, we list some of the
layer 2 technologies for which an IPv6 specification has been
developed. It is provided for informational purposes only and may
not be complete.
- Transmission of IPv6 Packets over Ethernet Networks [RFC2464]
- IPv6 over ATM Networks [RFC2492]
- Transmission of IPv6 Packets over Frame Relay Networks
- Transmission of IPv6 Packets over IEEE 1394 Networks [RFC3146]
- Transmission of IPv6, IPv4, and Address Resolution Protocol (ARP)
Packets over Fibre Channel [RFC4338]
- Transmission of IPv6 Packets over IEEE 802.15.4 Networks [RFC4944]
- Transmission of IPv6 via the IPv6 Convergence Sublayer over IEEE
802.16 Networks [RFC5121]
- IP version 6 over PPP [RFC5072]
In addition to traditional physical link-layers, it is also possible
to tunnel IPv6 over other protocols. Examples include:
- Teredo: Tunneling IPv6 over UDP through Network Address
Translations (NATs) [RFC4380]
- Section 3 of "Basic Transition Mechanisms for IPv6 Hosts and
5. IP Layer
5.1. Internet Protocol Version 6 - RFC 2460
The Internet Protocol Version 6 is specified in [RFC2460]. This
specification MUST be supported.
Any unrecognized extension headers or options MUST be processed as
described in RFC 2460.
The node MUST follow the packet transmission rules in RFC 2460.
Nodes MUST always be able to send, receive, and process fragment
headers. All conformant IPv6 implementations MUST be capable of
sending and receiving IPv6 packets; the forwarding functionality MAY
be supported. Overlapping fragments MUST be handled as described in
RFC 2460 specifies extension headers and the processing for these
An IPv6 node MUST be able to process these headers. An exception is
Routing Header type 0 (RH0), which was deprecated by [RFC5095] due to
security concerns and which MUST be treated as an unrecognized
All nodes SHOULD support the setting and use of the IPv6 Flow Label
field as defined in the IPv6 Flow Label specification [RFC6437].
Forwarding nodes such as routers and load distributors MUST NOT
depend only on Flow Label values being uniformly distributed. It is
RECOMMENDED that source hosts support the flow label by setting the
Flow Label field for all packets of a given flow to the same value
chosen from an approximation to a discrete uniform distribution.
5.2. Neighbor Discovery for IPv6 - RFC 4861
Neighbor Discovery is defined in [RFC4861]; the definition was
updated by [RFC5942]. Neighbor Discovery SHOULD be supported. RFC
Unless specified otherwise (in a document that covers operating IP
over a particular link type) this document applies to all link
types. However, because ND uses link-layer multicast for some of
its services, it is possible that on some link types (e.g., Non-
Broadcast Multi-Access (NBMA) links), alternative protocols or
mechanisms to implement those services will be specified (in the
appropriate document covering the operation of IP over a
particular link type). The services described in this document
that are not directly dependent on multicast, such as Redirects,
next-hop determination, Neighbor Unreachability Detection, etc.,
are expected to be provided as specified in this document. The
details of how one uses ND on NBMA links are addressed in
Some detailed analysis of Neighbor Discovery follows:
Router Discovery is how hosts locate routers that reside on an
attached link. Hosts MUST support Router Discovery functionality.
Prefix Discovery is how hosts discover the set of address prefixes
that define which destinations are on-link for an attached link.
Hosts MUST support Prefix Discovery.
Hosts MUST also implement Neighbor Unreachability Detection (NUD) for
all paths between hosts and neighboring nodes. NUD is not required
for paths between routers. However, all nodes MUST respond to
unicast Neighbor Solicitation (NS) messages.
Hosts MUST support the sending of Router Solicitations and the
receiving of Router Advertisements. The ability to understand
individual Router Advertisement options is dependent on supporting
the functionality making use of the particular option.
All nodes MUST support the sending and receiving of Neighbor
Solicitation (NS) and Neighbor Advertisement (NA) messages. NS and
NA messages are required for Duplicate Address Detection (DAD).
Hosts SHOULD support the processing of Redirect functionality.
Routers MUST support the sending of Redirects, though not necessarily
for every individual packet (e.g., due to rate limiting). Redirects
are only useful on networks supporting hosts. In core networks
dominated by routers, Redirects are typically disabled. The sending
of Redirects SHOULD be disabled by default on backbone routers. They
MAY be enabled by default on routers intended to support hosts on
"IPv6 Host-to-Router Load Sharing" [RFC4311] includes additional
recommendations on how to select from a set of available routers.
[RFC4311] SHOULD be supported.
5.3. Default Router Preferences and More-Specific Routes - RFC 4191
"Default Router Preferences and More-Specific Routes" [RFC4191]
provides support for nodes attached to multiple (different) networks,
each providing routers that advertise themselves as default routers
via Router Advertisements. In some scenarios, one router may provide
connectivity to destinations the other router does not, and choosing
the "wrong" default router can result in reachability failures. In
such cases, RFC 4191 can help.
Small Office/Home Office (SOHO) deployments supported by routers
adhering to [RFC6204] use RFC 4191 to advertise routes to certain
local destinations. Consequently, nodes that will be deployed in
SOHO environments SHOULD implement RFC 4191.
5.4. SEcure Neighbor Discovery (SEND) - RFC 3971
SEND [RFC3971] and Cryptographically Generated Address (CGA)
[RFC3972] provide a way to secure the message exchanges of Neighbor
Discovery. SEND is a new technology in that it has no IPv4
counterpart, but it has significant potential to address certain
classes of spoofing attacks. While there have been some
implementations of SEND, there has been only limited deployment
experience to date in using the technology. In addition, the IETF
working group Cga & Send maIntenance (csi) is currently working on
additional extensions intended to make SEND more attractive for
At this time, SEND is considered optional, and IPv6 nodes MAY provide
5.5. IPv6 Router Advertisement Flags Option - RFC 5175
Router Advertisements include an 8-bit field of single-bit Router
Advertisement flags. The Router Advertisement Flags Option extends
the number of available flag bits by 48 bits. At the time of this
writing, 6 of the original 8 single-bit flags have been assigned,
while 2 remain available for future assignment. No flags have been
defined that make use of the new option, and thus, strictly speaking,
there is no requirement to implement the option today. However,
implementations that are able to pass unrecognized options to a
higher-level entity that may be able to understand them (e.g., a
user-level process using a "raw socket" facility) MAY take steps to
handle the option in anticipation of a future usage.
5.6. Path MTU Discovery and Packet Size
5.6.1. Path MTU Discovery - RFC 1981
"Path MTU Discovery for IP version 6" [RFC1981] SHOULD be supported.
It is strongly recommended that IPv6 nodes implement Path MTU
Discovery [RFC1981], in order to discover and take advantage of
path MTUs greater than 1280 octets. However, a minimal IPv6
implementation (e.g., in a boot ROM) may simply restrict itself to
sending packets no larger than 1280 octets, and omit
implementation of Path MTU Discovery.
The rules in [RFC2460] and [RFC5722] MUST be followed for packet
fragmentation and reassembly.
One operational issue with Path MTU Discovery occurs when firewalls
block ICMP Packet Too Big messages. Path MTU Discovery relies on
such messages to determine what size messages can be successfully
sent. "Packetization Layer Path MTU Discovery" [RFC4821] avoids
having a dependency on Packet Too Big messages.
5.7. IPv6 Jumbograms - RFC 2675
IPv6 Jumbograms [RFC2675] are an optional extension that allow the
sending of IP datagrams larger than 65.535 bytes. IPv6 Jumbograms
make use of IPv6 hop-by-hop options and are only suitable on paths in
which every hop and link are capable of supporting Jumbograms (e.g.,
within a campus or datacenter). To date, few implementations exist,
and there is essentially no reported experience from usage.
Consequently, IPv6 Jumbograms [RFC2675] remain optional at this time.
5.8. ICMP for the Internet Protocol Version 6 (IPv6) - RFC 4443
ICMPv6 [RFC4443] MUST be supported. "Extended ICMP to Support Multi-
Part Messages" [RFC4884] MAY be supported.
5.9.1. IP Version 6 Addressing Architecture - RFC 4291
The IPv6 Addressing Architecture [RFC4291] MUST be supported.
5.9.2. IPv6 Stateless Address Autoconfiguration - RFC 4862
Hosts MUST support IPv6 Stateless Address Autoconfiguration as
defined in [RFC4862]. Configuration of static address(es) may be
supported as well.
Nodes that are routers MUST be able to generate link-local addresses
as described in [RFC4862].
From RFC 4862:
The autoconfiguration process specified in this document applies
only to hosts and not routers. Since host autoconfiguration uses
information advertised by routers, routers will need to be
configured by some other means. However, it is expected that
routers will generate link-local addresses using the mechanism
described in this document. In addition, routers are expected to
successfully pass the Duplicate Address Detection procedure
described in this document on all addresses prior to assigning
them to an interface.
All nodes MUST implement Duplicate Address Detection. Quoting from
Section 5.4 of RFC 4862:
Duplicate Address Detection MUST be performed on all unicast
addresses prior to assigning them to an interface, regardless of
whether they are obtained through stateless autoconfiguration,
DHCPv6, or manual configuration, with the following [exceptions
"Optimistic Duplicate Address Detection (DAD) for IPv6" [RFC4429]
specifies a mechanism to reduce delays associated with generating
addresses via Stateless Address Autoconfiguration [RFC4862]. RFC
4429 was developed in conjunction with Mobile IPv6 in order to reduce
the time needed to acquire and configure addresses as devices quickly
move from one network to another, and it is desirable to minimize
transition delays. For general purpose devices, RFC 4429 remains
optional at this time.
5.9.3. Privacy Extensions for Address Configuration in IPv6 - RFC 4941
Privacy Extensions for Stateless Address Autoconfiguration [RFC4941]
addresses a specific problem involving a client device whose user is
concerned about its activity or location being tracked. The problem
arises both for a static client and for one that regularly changes
its point of attachment to the Internet. When using Stateless
Address Autoconfiguration [RFC4862], the Interface Identifier portion
of formed addresses stays constant and is globally unique. Thus,
although a node's global IPv6 address will change if it changes its
point of attachment, the Interface Identifier portion of those
addresses remains the same, making it possible for servers to track
the location of an individual device as it moves around or its
pattern of activity if it remains in one place. This may raise
privacy concerns as described in [RFC4862].
In such situations, RFC 4941 SHOULD be implemented. In other cases,
such as with dedicated servers in a data center, RFC 4941 provides
limited or no benefit.
Implementers of RFC 4941 should be aware that certain addresses are
reserved and should not be chosen for use as temporary addresses.
Consult "Reserved IPv6 Interface Identifiers" [RFC5453] for more
5.9.4. Default Address Selection for IPv6 - RFC 3484
The rules specified in the Default Address Selection for IPv6
[RFC3484] document MUST be implemented. IPv6 nodes will need to deal
with multiple addresses configured simultaneously.
5.9.5. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315
DHCPv6 [RFC3315] can be used to obtain and configure addresses. In
general, a network may provide for the configuration of addresses
through Router Advertisements, DHCPv6, or both. There will be a wide
range of IPv6 deployment models and differences in address assignment
requirements, some of which may require DHCPv6 for address
assignment. Consequently, all hosts SHOULD implement address
configuration via DHCPv6.
In the absence of a router, IPv6 nodes using DHCP for address
assignment MAY initiate DHCP to obtain IPv6 addresses and other
configuration information, as described in Section 5.5.2 of
5.10. Multicast Listener Discovery (MLD) for IPv6
Nodes that need to join multicast groups MUST support MLDv1
[RFC2710]. MLDv1 is needed by any node that is expected to receive
and process multicast traffic. Note that Neighbor Discovery (as used
on most link types -- see Section 5.2) depends on multicast and
requires that nodes join Solicited Node multicast addresses.
MLDv2 [RFC3810] extends the functionality of MLDv1 by supporting
Source-Specific Multicast. The original MLDv2 protocol [RFC3810]
supporting Source-Specific Multicast [RFC4607] supports two types of
"filter modes". Using an INCLUDE filter, a node indicates a
multicast group along with a list of senders for the group from which
it wishes to receive traffic. Using an EXCLUDE filter, a node
indicates a multicast group along with a list of senders from which
it wishes to exclude receiving traffic. In practice, operations to
block source(s) using EXCLUDE mode are rarely used but add
considerable implementation complexity to MLDv2. Lightweight MLDv2
[RFC5790] is a simplified subset of the original MLDv2 specification
that omits EXCLUDE filter mode to specify undesired source(s).
Nodes SHOULD implement either MLDv2 [RFC3810] or Lightweight MLDv2
[RFC5790]. Specifically, nodes supporting applications using Source-
Specific Multicast that expect to take advantage of MLDv2's EXCLUDE
functionality [RFC3810] MUST support MLDv2 as defined in [RFC3810],
[RFC4604], and [RFC4607]. Nodes supporting applications that expect
to only take advantage of MLDv2's INCLUDE functionality as well as
Any-Source Multicast will find it sufficient to support MLDv2 as
defined in [RFC5790].
If a node only supports applications that use Any-Source Multicast
(i.e, they do not use Source-Specific Multicast), implementing MLDv1
[RFC2710] is sufficient. In all cases, however, nodes are strongly
encouraged to implement MLDv2 or Lightweight MLDv2 rather than MLDv1,
as the presence of a single MLDv1 participant on a link requires that
all other nodes on the link operate in version 1 compatibility mode.
When MLDv1 is used, the rules in the Source Address Selection for the
Multicast Listener Discovery (MLD) Protocol [RFC3590] MUST be
6. DHCP versus Router Advertisement Options for Host Configuration
In IPv6, there are two main protocol mechanisms for propagating
configuration information to hosts: Router Advertisements (RAs) and
DHCP. Historically, RA options have been restricted to those deemed
essential for basic network functioning and for which all nodes are
configured with exactly the same information. Examples include the
Prefix Information Options, the MTU option, etc. On the other hand,
DHCP has generally been preferred for configuration of more general
parameters and for parameters that may be client-specific. That
said, identifying the exact line on whether a particular option
should be configured via DHCP versus an RA option has not always been
easy. Generally speaking, however, there has been a desire to define
only one mechanism for configuring a given option, rather than
defining multiple (different) ways of configuring the same
One issue with having multiple ways of configuring the same
information is that interoperability suffers if a host chooses one
mechanism but the network operator chooses a different mechanism.
For "closed" environments, where the network operator has significant
influence over what devices connect to the network and thus what
configuration mechanisms they support, the operator may be able to
ensure that a particular mechanism is supported by all connected
hosts. In more open environments, however, where arbitrary devices
may connect (e.g., a WIFI hotspot), problems can arise. To maximize
interoperability in such environments, hosts would need to implement
multiple configuration mechanisms to ensure interoperability.
Originally, in IPv6, configuring information about DNS servers was
performed exclusively via DHCP. In 2007, an RA option was defined
but was published as Experimental [RFC5006]. In 2010, "IPv6 Router
Advertisement Options for DNS Configuration" [RFC6106] was published
as a Standards Track document. Consequently, DNS configuration
information can now be learned either through DHCP or through RAs.
Hosts will need to decide which mechanism (or whether both) should be
implemented. Specific guidance regarding DNS server discovery is
discussed in Section 7.
7. DNS and DHCP
DNS is described in [RFC1034], [RFC1035], [RFC3363], and [RFC3596].
Not all nodes will need to resolve names; those that will never need
to resolve DNS names do not need to implement resolver functionality.
However, the ability to resolve names is a basic infrastructure
capability on which applications rely, and most nodes will need to
provide support. All nodes SHOULD implement stub-resolver [RFC1034]
functionality, as in [RFC1034], Section 5.3.1, with support for:
- AAAA type Resource Records [RFC3596];
- reverse addressing in ip6.arpa using PTR records [RFC3596];
- Extension Mechanisms for DNS (EDNS0) [RFC2671] to allow for DNS
packet sizes larger than 512 octets.
Those nodes are RECOMMENDED to support DNS security extensions
[RFC4033] [RFC4034] [RFC4035].
Those nodes are NOT RECOMMENDED to support the experimental A6
Resource Records [RFC3363].
7.2. Dynamic Host Configuration Protocol for IPv6 (DHCPv6) - RFC 3315
7.2.1. Other Configuration Information
IPv6 nodes use DHCP [RFC3315] to obtain address configuration
information (see Section 5.9.5) and to obtain additional (non-
address) configuration. If a host implementation supports
applications or other protocols that require configuration that is
only available via DHCP, hosts SHOULD implement DHCP. For
specialized devices on which no such configuration need is present,
DHCP may not be necessary.
An IPv6 node can use the subset of DHCP (described in [RFC3736]) to
obtain other configuration information.
7.2.2. Use of Router Advertisements in Managed Environments
Nodes using the Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
are expected to determine their default router information and on-
link prefix information from received Router Advertisements.
7.3. IPv6 Router Advertisement Options for DNS Configuration - RFC 6106
Router Advertisements have historically limited options to those that
are critical to basic IPv6 functioning. Originally, DNS
configuration was not included as an RA option, and DHCP was the
recommended way to obtain DNS configuration information. Over time,
the thinking surrounding such an option has evolved. It is now
generally recognized that few nodes can function adequately without
having access to a working DNS resolver. [RFC5006] was published as
an Experimental document in 2007, and recently, a revised version was
placed on the Standards Track [RFC6106].
Implementations SHOULD implement the DNS RA option [RFC6106].
8. IPv4 Support and Transition
IPv6 nodes MAY support IPv4.
8.1. Transition Mechanisms
8.1.1. Basic Transition Mechanisms for IPv6 Hosts and Routers - RFC
If an IPv6 node implements dual stack and tunneling, then [RFC4213]
MUST be supported.
9. Application Support
9.1. Textual Representation of IPv6 Addresses - RFC 5952
Software that allows users and operators to input IPv6 addresses in
text form SHOULD support "A Recommendation for IPv6 Address Text
9.2. Application Programming Interfaces (APIs)
There are a number of IPv6-related APIs. This document does not
mandate the use of any, because the choice of API does not directly
relate to on-the-wire behavior of protocols. Implementers, however,
would be advised to consider providing a common API or reviewing
existing APIs for the type of functionality they provide to
"Basic Socket Interface Extensions for IPv6" [RFC3493] provides IPv6
functionality used by typical applications. Implementers should note
that RFC3493 has been picked up and further standardized by the
Portable Operating System Interface (POSIX) [POSIX].
"Advanced Sockets Application Program Interface (API) for IPv6"
[RFC3542] provides access to advanced IPv6 features needed by
diagnostic and other more specialized applications.
"IPv6 Socket API for Source Address Selection" [RFC5014] provides
facilities that allow an application to override the default Source
Address Selection rules of [RFC3484].
"Socket Interface Extensions for Multicast Source Filters" [RFC3678]
provides support for expressing source filters on multicast group
"Extension to Sockets API for Mobile IPv6" [RFC4584] provides
application support for accessing and enabling Mobile IPv6 [RFC6275]
Mobile IPv6 [RFC6275] and associated specifications [RFC3776]
[RFC4877] allow a node to change its point of attachment within the
Internet, while maintaining (and using) a permanent address. All
communication using the permanent address continues to proceed as
expected even as the node moves around. The definition of Mobile IP
includes requirements for the following types of nodes:
- mobile nodes
- correspondent nodes with support for route optimization
- home agents
- all IPv6 routers
At the present time, Mobile IP has seen only limited implementation
and no significant deployment, partly because it originally assumed
an IPv6-only environment rather than a mixed IPv4/IPv6 Internet.
Recently, additional work has been done to support mobility in mixed-
mode IPv4 and IPv6 networks [RFC5555].
More usage and deployment experience is needed with mobility before
any specific approach can be recommended for broad implementation in
all hosts and routers. Consequently, [RFC6275], [RFC5555], and
associated standards such as [RFC4877] are considered a MAY at this
This section describes the specification for security for IPv6 nodes.
Achieving security in practice is a complex undertaking. Operational
procedures, protocols, key distribution mechanisms, certificate
management approaches, etc., are all components that impact the level
of security actually achieved in practice. More importantly,
deficiencies or a poor fit in any one individual component can
significantly reduce the overall effectiveness of a particular
IPsec provides channel security at the Internet layer, making it
possible to provide secure communication for all (or a subset of)
communication flows at the IP layer between pairs of internet nodes.
IPsec provides sufficient flexibility and granularity that individual
TCP connections can (selectively) be protected, etc.
Although IPsec can be used with manual keying in some cases, such
usage has limited applicability and is not recommended.
A range of security technologies and approaches proliferate today
(e.g., IPsec, Transport Layer Security (TLS), Secure SHell (SSH),
etc.) No one approach has emerged as an ideal technology for all
needs and environments. Moreover, IPsec is not viewed as the ideal
security technology in all cases and is unlikely to displace the
Previously, IPv6 mandated implementation of IPsec and recommended the
key management approach of IKE. This document updates that
recommendation by making support of the IPsec Architecture [RFC4301]
a SHOULD for all IPv6 nodes. Note that the IPsec Architecture
requires (e.g., Section 4.5 of RFC 4301) the implementation of both
manual and automatic key management. Currently, the default
automated key management protocol to implement is IKEv2 [RFC5996].
This document recognizes that there exists a range of device types
and environments where approaches to security other than IPsec can be
justified. For example, special-purpose devices may support only a
very limited number or type of applications, and an application-
specific security approach may be sufficient for limited management
or configuration capabilities. Alternatively, some devices may run
on extremely constrained hardware (e.g., sensors) where the full
IPsec Architecture is not justified.
"Security Architecture for the Internet Protocol" [RFC4301] SHOULD be
supported by all IPv6 nodes. Note that the IPsec Architecture
requires (e.g., Section 4.5 of [RFC4301]) the implementation of both
manual and automatic key management. Currently, the default
automated key management protocol to implement is IKEv2. As required
in [RFC4301], IPv6 nodes implementing the IPsec Architecture MUST
implement ESP [RFC4303] and MAY implement AH [RFC4302].
11.2. Transforms and Algorithms
The current set of mandatory-to-implement algorithms for the IPsec
Architecture are defined in "Cryptographic Algorithm Implementation
Requirements For ESP and AH" [RFC4835]. IPv6 nodes implementing the
IPsec Architecture MUST conform to the requirements in [RFC4835].
Preferred cryptographic algorithms often change more frequently than
security protocols. Therefore, implementations MUST allow for
migration to new algorithms, as RFC 4835 is replaced or updated in
The current set of mandatory-to-implement algorithms for IKEv2 are
defined in "Cryptographic Algorithms for Use in the Internet Key
Exchange Version 2 (IKEv2)" [RFC4307]. IPv6 nodes implementing IKEv2
MUST conform to the requirements in [RFC4307] and/or any future
updates or replacements to [RFC4307].
12. Router-Specific Functionality
This section defines general host considerations for IPv6 nodes that
act as routers. Currently, this section does not discuss routing-
12.1. IPv6 Router Alert Option - RFC 2711
The IPv6 Router Alert Option [RFC2711] is an optional IPv6 Hop-by-Hop
Header that is used in conjunction with some protocols (e.g., RSVP
[RFC2205] or Multicast Listener Discovery (MLD) [RFC2710]). The
Router Alert option will need to be implemented whenever protocols
that mandate its usage (e.g., MLD) are implemented. See
12.2. Neighbor Discovery for IPv6 - RFC 4861
Sending Router Advertisements and processing Router Solicitations
MUST be supported.
Section 7 of [RFC6275] includes some mobility-specific extensions to
Neighbor Discovery. Routers SHOULD implement Sections 7.3 and 7.5,
even if they do not implement Home Agent functionality.
12.3. Stateful Address Autoconfiguration (DHCPv6) - RFC 3315
A single DHCP server ([RFC3315] or [RFC4862]) can provide
configuration information to devices directly attached to a shared
link, as well as to devices located elsewhere within a site.
Communication between a client and a DHCP server located on different
links requires the use of DHCP relay agents on routers.
In simple deployments, consisting of a single router and either a
single LAN or multiple LANs attached to the single router, together
with a WAN connection, a DHCP server embedded within the router is
one common deployment scenario (e.g., [RFC6204]). However, there is
no need for relay agents in such scenarios.
In more complex deployment scenarios, such as within enterprise or
service provider networks, the use of DHCP requires some level of
configuration, in order to configure relay agents, DHCP servers, etc.
In such environments, the DHCP server might even be run on a
traditional server, rather than as part of a router.
Because of the wide range of deployment scenarios, support for DHCP
server functionality on routers is optional. However, routers
targeted for deployment within more complex scenarios (as described
above) SHOULD support relay agent functionality. Note that "Basic
Requirements for IPv6 Customer Edge Routers" [RFC6204] requires
implementation of a DHCPv6 server function in IPv6 Customer Edge (CE)
13. Network Management
Network management MAY be supported by IPv6 nodes. However, for IPv6
nodes that are embedded devices, network management may be the only
possible way of controlling these nodes.
13.1. Management Information Base (MIB) Modules
The following two MIB modules SHOULD be supported by nodes that
support a Simple Network Management Protocol (SNMP) agent.
13.1.1. IP Forwarding Table MIB
The IP Forwarding Table MIB [RFC4292] SHOULD be supported by nodes
that support an SNMP agent.
13.1.2. Management Information Base for the Internet Protocol (IP)
The IP MIB [RFC4293] SHOULD be supported by nodes that support an
14. Security Considerations
This document does not directly affect the security of the Internet,
beyond the security considerations associated with the individual
Security is also discussed in Section 11 above.
15. Authors and Acknowledgments
15.1. Authors and Acknowledgments (Current Document)
For this version of the IPv6 Node Requirements document, the authors
would like to thank Hitoshi Asaeda, Brian Carpenter, Tim Chown, Ralph
Droms, Sheila Frankel, Sam Hartman, Bob Hinden, Paul Hoffman, Pekka
Savola, Yaron Sheffer, and Dave Thaler for their comments.
15.2. Authors and Acknowledgments from RFC 4279
The original version of this document (RFC 4279) was written by the
IPv6 Node Requirements design team:
Jun-ichiro Itojun Hagino
The authors would like to thank Ran Atkinson, Jim Bound, Brian
Carpenter, Ralph Droms, Christian Huitema, Adam Machalek, Thomas
Narten, Juha Ollila, and Pekka Savola for their comments. Thanks to
Mark Andrews for comments and corrections on DNS text. Thanks to
Alfred Hoenes for tracking the updates to various RFCs.
16. Appendix: Changes from RFC 4294
There have been many editorial clarifications as well as significant
additions and updates. While this section highlights some of the
changes, readers should not rely on this section for a comprehensive
list of all changes.
1. Updated the Introduction to indicate that this document is an
applicability statement and is aimed at general nodes.
2. Significantly updated the section on Mobility protocols, adding
references and downgrading previous SHOULDs to MAYs.
3. Changed Sub-IP Layer section to just list relevant RFCs, and
added some more RFCs.
4. Added section on SEND (it is a MAY).
5. Revised section on Privacy Extensions [RFC4941] to add more
nuance to recommendation.
6. Completely revised IPsec/IKEv2 section, downgrading overall
recommendation to a SHOULD.
7. Upgraded recommendation of DHCPv6 to SHOULD.
8. Added background section on DHCP versus RA options, added SHOULD
recommendation for DNS configuration via RAs [RFC6106], and
cleaned up DHCP recommendations.
9. Added recommendation that routers implement Sections 7.3 and 7.5
10. Added pointer to subnet clarification document [RFC5942].
11. Added text that "IPv6 Host-to-Router Load Sharing" [RFC4311]
SHOULD be implemented.
12. Added reference to [RFC5722] (Overlapping Fragments), and made
it a MUST to implement.
13. Made "A Recommendation for IPv6 Address Text Representation"
[RFC5952] a SHOULD.
14. Removed mention of "DNAME" from the discussion about [RFC3363].
15. Numerous updates to reflect newer versions of IPv6 documents,
including [RFC4443], [RFC4291], [RFC3596], and [RFC4213].
16. Removed discussion of "Managed" and "Other" flags in RAs. There
is no consensus at present on how to process these flags, and
discussion of their semantics was removed in the most recent
update of Stateless Address Autoconfiguration [RFC4862].
17. Added many more references to optional IPv6 documents.
18. Made "A Recommendation for IPv6 Address Text Representation"
[RFC5952] a SHOULD.
19. Added reference to [RFC5722] (Overlapping Fragments), and made
it a MUST to implement.
20. Updated MLD section to include reference to Lightweight MLD
21. Added SHOULD recommendation for "Default Router Preferences and
More-Specific Routes" [RFC4191].
22. Made "IPv6 Flow Label Specification" [RFC6437] a SHOULD.
17.1. Normative References
[RFC1034] Mockapetris, P., "Domain names - concepts and facilities",
STD 13, RFC 1034, November 1987.
[RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987.
[RFC1981] McCann, J., Deering, S., and J. Mogul, "Path MTU Discovery
for IP version 6", RFC 1981, August 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)",
RFC 2671, August 1999.
[RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710,
[RFC2711] Partridge, C. and A. Jackson, "IPv6 Router Alert Option",
RFC 2711, October 1999.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3484] Draves, R., "Default Address Selection for Internet
Protocol version 6 (IPv6)", RFC 3484, February 2003.
[RFC3590] Haberman, B., "Source Address Selection for the Multicast
Listener Discovery (MLD) Protocol", RFC 3590,
[RFC3596] Thomson, S., Huitema, C., Ksinant, V., and M. Souissi,
"DNS Extensions to Support IP Version 6", RFC 3596,
[RFC3736] Droms, R., "Stateless Dynamic Host Configuration Protocol
(DHCP) Service for IPv6", RFC 3736, April 2004.
[RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "DNS Security Introduction and Requirements",
RFC 4033, March 2005.
[RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Resource Records for the DNS Security Extensions",
RFC 4034, March 2005.
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, March 2005.
[RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms
for IPv6 Hosts and Routers", RFC 4213, October 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC4292] Haberman, B., "IP Forwarding Table MIB", RFC 4292,
[RFC4293] Routhier, S., "Management Information Base for the
Internet Protocol (IP)", RFC 4293, April 2006.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, December 2005.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, December 2005.
[RFC4307] Schiller, J., "Cryptographic Algorithms for Use in the
Internet Key Exchange Version 2 (IKEv2)", RFC 4307,
[RFC4311] Hinden, R. and D. Thaler, "IPv6 Host-to-Router Load
Sharing", RFC 4311, November 2005.
[RFC4443] Conta, A., Deering, S., and M. Gupta, "Internet Control
Message Protocol (ICMPv6) for the Internet Protocol
Version 6 (IPv6) Specification", RFC 4443, March 2006.
[RFC4604] Holbrook, H., Cain, B., and B. Haberman, "Using Internet
Group Management Protocol Version 3 (IGMPv3) and Multicast
Listener Discovery Protocol Version 2 (MLDv2) for Source-
Specific Multicast", RFC 4604, August 2006.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, August 2006.
[RFC4835] Manral, V., "Cryptographic Algorithm Implementation
Requirements for Encapsulating Security Payload (ESP) and
Authentication Header (AH)", RFC 4835, April 2007.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007.
[RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy
Extensions for Stateless Address Autoconfiguration in
IPv6", RFC 4941, September 2007.
[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095,
[RFC5453] Krishnan, S., "Reserved IPv6 Interface Identifiers",
RFC 5453, February 2009.
[RFC5722] Krishnan, S., "Handling of Overlapping IPv6 Fragments",
RFC 5722, December 2009.
[RFC5790] Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet
Group Management Protocol Version 3 (IGMPv3) and Multicast
Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790,
[RFC5942] Singh, H., Beebee, W., and E. Nordmark, "IPv6 Subnet
Model: The Relationship between Links and Subnet
Prefixes", RFC 5942, July 2010.
[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
Address Text Representation", RFC 5952, August 2010.
[RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
"Internet Key Exchange Protocol Version 2 (IKEv2)",
RFC 5996, September 2010.
[RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Options for DNS Configuration",
RFC 6106, November 2010.
[RFC6204] Singh, H., Beebee, W., Donley, C., Stark, B., and O.
Troan, "Basic Requirements for IPv6 Customer Edge
Routers", RFC 6204, April 2011.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437, November 2011.
17.2. Informative References
[DODv6] DISR IPv6 Standards Technical Working Group, "DoD IPv6
Standard Profiles For IPv6 Capable Products Version 5.0",
[POSIX] IEEE, "IEEE Std. 1003.1-2008 Standard for Information
Technology -- Portable Operating System Interface (POSIX),
ISO/IEC 9945:2009", <http://www.ieee.org>.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981.
[RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC2464] Crawford, M., "Transmission of IPv6 Packets over Ethernet
Networks", RFC 2464, December 1998.
[RFC2491] Armitage, G., Schulter, P., Jork, M., and G. Harter, "IPv6
over Non-Broadcast Multiple Access (NBMA) networks",
RFC 2491, January 1999.
[RFC2492] Armitage, G., Schulter, P., and M. Jork, "IPv6 over ATM
Networks", RFC 2492, January 1999.
[RFC2590] Conta, A., Malis, A., and M. Mueller, "Transmission of
IPv6 Packets over Frame Relay Networks Specification",
RFC 2590, May 1999.
[RFC2675] Borman, D., Deering, S., and R. Hinden, "IPv6 Jumbograms",
RFC 2675, August 1999.
[RFC3146] Fujisawa, K. and A. Onoe, "Transmission of IPv6 Packets
over IEEE 1394 Networks", RFC 3146, October 2001.
[RFC3363] 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,
[RFC3493] Gilligan, R., Thomson, S., Bound, J., McCann, J., and W.
Stevens, "Basic Socket Interface Extensions for IPv6",
RFC 3493, February 2003.
[RFC3542] Stevens, W., Thomas, M., Nordmark, E., and T. Jinmei,
"Advanced Sockets Application Program Interface (API) for
IPv6", RFC 3542, May 2003.
[RFC3678] Thaler, D., Fenner, B., and B. Quinn, "Socket Interface
Extensions for Multicast Source Filters", RFC 3678,
[RFC3776] Arkko, J., Devarapalli, V., and F. Dupont, "Using IPsec to
Protect Mobile IPv6 Signaling Between Mobile Nodes and
Home Agents", RFC 3776, June 2004.
[RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure
Neighbor Discovery (SEND)", RFC 3971, March 2005.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, March 2005.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, November 2005.
[RFC4302] Kent, S., "IP Authentication Header", RFC 4302,
[RFC4338] DeSanti, C., Carlson, C., and R. Nixon, "Transmission of
IPv6, IPv4, and Address Resolution Protocol (ARP) Packets
over Fibre Channel", RFC 4338, January 2006.
[RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through
Network Address Translations (NATs)", RFC 4380,
[RFC4429] Moore, N., "Optimistic Duplicate Address Detection (DAD)
for IPv6", RFC 4429, April 2006.
[RFC4584] Chakrabarti, S. and E. Nordmark, "Extension to Sockets API
for Mobile IPv6", RFC 4584, July 2006.
[RFC4821] Mathis, M. and J. Heffner, "Packetization Layer Path MTU
Discovery", RFC 4821, March 2007.
[RFC4877] Devarapalli, V. and F. Dupont, "Mobile IPv6 Operation with
IKEv2 and the Revised IPsec Architecture", RFC 4877,
[RFC4884] Bonica, R., Gan, D., Tappan, D., and C. Pignataro,
"Extended ICMP to Support Multi-Part Messages", RFC 4884,
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, September 2007.
[RFC5006] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Option for DNS Configuration",
RFC 5006, September 2007.
[RFC5014] Nordmark, E., Chakrabarti, S., and J. Laganier, "IPv6
Socket API for Source Address Selection", RFC 5014,
[RFC5072] S.Varada, Haskins, D., and E. Allen, "IP Version 6 over
PPP", RFC 5072, September 2007.
[RFC5121] Patil, B., Xia, F., Sarikaya, B., Choi, JH., and S.
Madanapalli, "Transmission of IPv6 via the IPv6
Convergence Sublayer over IEEE 802.16 Networks", RFC 5121,
[RFC5555] Soliman, H., "Mobile IPv6 Support for Dual Stack Hosts and
Routers", RFC 5555, June 2009.
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
[USGv6] National Institute of Standards and Technology, "A Profile
for IPv6 in the U.S. Government - Version 1.0", July 2008,
SRI International, Inc.
333 Ravenswood Ave.
Menlo Park, CA 94025
Phone: +1 443 502 5815
200 South Mathilda Ave.
Sunnyvale, CA 94086
Phone: +1 650 283 8068
3039 Cornwallis Ave.
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Phone: +1 919 254 7798