   Link: manifest
   Link: license
   Link: canonical
   [ ] Open main menu
     * Home
     * Random
     * Nearby
     * Log in
     * Donate
     * About Wikipedia
     * Disclaimers
   Wikipedia
   _____________________
   Search

                                      IPv6

   Article Talk
     * Language
     * Watch
     * Edit

   Parts of this article (those related to RFC 8200 and RFC 8201) need to be  
   updated. Please help update this article to reflect recent events or newly 
   available information. (July 2017)                                         

   Internet Protocol version 6 (IPv6) is the most recent version of the
   Internet Protocol (IP), the communications protocol that provides an
   identification and location system for computers on networks and routes
   traffic across the Internet. IPv6 was developed by the Internet
   Engineering Task Force (IETF) to deal with the long-anticipated problem of
   IPv4 address exhaustion, and is intended to replace IPv4.^[1] In December
   1998, IPv6 became a Draft Standard for the IETF,^[2] which subsequently
   ratified it as an Internet Standard on 14 July 2017.^[3]^[4]

                          Internet Protocol Version 6
   Communication protocol
   Diagram of an IPv6 header
   IPv6 header  
   Purpose      Internetworking protocol        
   Developer(s) Internet Engineering Task Force 
   Introduction December 1995; 26 years ago     
   Based on     IPv4                            
   OSI layer    Network layer                   
   RFC(s)       2460, 8200                      

   Devices on the Internet are assigned a unique IP address for
   identification and location definition. With the rapid growth of the
   Internet after commercialization in the 1990s, it became evident that far
   more addresses would be needed to connect devices than the IPv4 address
   space had available. By 1998, the IETF had formalized the successor
   protocol. IPv6 uses 128-bit addresses, theoretically allowing 2^128, or
   approximately 3.4×10^38 total addresses. The actual number is slightly
   smaller, as multiple ranges are reserved for special use or completely
   excluded from use. The two protocols are not designed to be interoperable,
   and thus direct communication between them is impossible, complicating the
   move to IPv6. However, several transition mechanisms have been devised to
   rectify this.

   IPv6 provides other technical benefits in addition to a larger addressing
   space. In particular, it permits hierarchical address allocation methods
   that facilitate route aggregation across the Internet, and thus limit the
   expansion of routing tables. The use of multicast addressing is expanded
   and simplified, and provides additional optimization for the delivery of
   services. Device mobility, security, and configuration aspects have been
   considered in the design of the protocol.

   IPv6 addresses are represented as eight groups of four hexadecimal digits
   each, separated by colons. The full representation may be shortened; for
   example, 2001:0db8:0000:0000:0000:8a2e:0370:7334 becomes
   2001:db8::8a2e:370:7334.

Contents

     * 1 Main features
     * 2 Motivation and origin
          * 2.1 IPv4 address exhaustion
     * 3 Comparison with IPv4
          * 3.1 Larger address space
          * 3.2 Multicasting
          * 3.3 Stateless address autoconfiguration (SLAAC)
          * 3.4 IPsec
          * 3.5 Simplified processing by routers
          * 3.6 Mobility
          * 3.7 Extension headers
               * 3.7.1 Jumbograms
     * 4 IPv6 packets
     * 5 Addressing
          * 5.1 Address representation
          * 5.2 Link-local address
          * 5.3 Address uniqueness and router solicitation
          * 5.4 Global addressing
     * 6 IPv6 in the Domain Name System
     * 7 Transition mechanisms
          * 7.1 Dual-stack IP implementation
          * 7.2 ISP customers with public-facing IPv6
          * 7.3 Tunneling
          * 7.4 IPv4-mapped IPv6 addresses
     * 8 Security
          * 8.1 Shadow networks
          * 8.2 IPv6 packet fragmentation
     * 9 Standardization through RFCs
          * 9.1 Working-group proposals
          * 9.2 RFC standardization
     * 10 Deployment
     * 11 See also
     * 12 References
     * 13 External links

Main featuresEdit

   [IMG] 
   Enlarge
   Glossary of terms used for IPv6 addresses

   IPv6 is an Internet Layer protocol for packet-switched internetworking and
   provides end-to-end datagram transmission across multiple IP networks,
   closely adhering to the design principles developed in the previous
   version of the protocol, Internet Protocol Version 4 (IPv4).

   In addition to offering more addresses, IPv6 also implements features not
   present in IPv4. It simplifies aspects of address configuration, network
   renumbering, and router announcements when changing network connectivity
   providers. It simplifies processing of packets in routers by placing the
   responsibility for packet fragmentation into the end points. The IPv6
   subnet size is standardized by fixing the size of the host identifier
   portion of an address to 64 bits.

   The addressing architecture of IPv6 is defined in
   Link: mw-deduplicated-inline-style
   RFC 4291 and allows three different types of transmission: unicast,
   anycast and multicast.^[5]^: 210 

Motivation and originEdit

  IPv4 address exhaustionEdit

   Main article: IPv4 address exhaustion
   [IMG] 
   Enlarge
   Decomposition of the dot-decimal IPv4 address representation to its binary
   value

   Internet Protocol Version 4 (IPv4) was the first publicly used version of
   the Internet Protocol. IPv4 was developed as a research project by the
   Defense Advanced Research Projects Agency (DARPA), a United States
   Department of Defense agency, before becoming the foundation for the
   Internet and the World Wide Web. IPv4 includes an addressing system that
   uses numerical identifiers consisting of 32 bits. These addresses are
   typically displayed in dot-decimal notation as decimal values of four
   octets, each in the range 0 to 255, or 8 bits per number. Thus, IPv4
   provides an addressing capability of 2^32 or approximately 4.3 billion
   addresses. Address exhaustion was not initially a concern in IPv4 as this
   version was originally presumed to be a test of DARPA's networking
   concepts.^[6] During the first decade of operation of the Internet, it
   became apparent that methods had to be developed to conserve address
   space. In the early 1990s, even after the redesign of the addressing
   system using a classless network model, it became clear that this would
   not suffice to prevent IPv4 address exhaustion, and that further changes
   to the Internet infrastructure were needed.^[7]

   The last unassigned top-level address blocks of 16 million IPv4 addresses
   were allocated in February 2011 by the Internet Assigned Numbers Authority
   (IANA) to the five regional Internet registries (RIRs).^[8] However, each
   RIR still has available address pools and is expected to continue with
   standard address allocation policies until one /8 Classless Inter-Domain
   Routing (CIDR) block remains. After that, only blocks of 1,024 addresses
   (/22) will be provided from the RIRs to a local Internet registry (LIR).
   As of September 2015, all of Asia-Pacific Network Information Centre
   (APNIC), the Réseaux IP Européens Network Coordination Centre (RIPE_NCC),
   Latin America and Caribbean Network Information Centre (LACNIC), and
   American Registry for Internet Numbers (ARIN) have reached this
   stage.^[9]^[10]^[11] This leaves African Network Information Center
   (AFRINIC) as the sole regional internet registry that is still using the
   normal protocol for distributing IPv4 addresses. As of November 2018,
   AFRINIC's minimum allocation is /22 or 1024 IPv4 addresses. A LIR may
   receive additional allocation when about 80% of all the address space has
   been utilized.^[12]

   RIPE NCC announced that it had fully run out of IPv4 addresses on 25
   November 2019,^[13] and called for greater progress on the adoption of
   IPv6.

   It is widely expected that the Internet will use IPv4 alongside IPv6 for
   the foreseeable future.^[by whom?]

Comparison with IPv4Edit

   On the Internet, data is transmitted in the form of network packets. IPv6
   specifies a new packet format, designed to minimize packet header
   processing by routers.^[2]^[14] Because the headers of IPv4 packets and
   IPv6 packets are significantly different, the two protocols are not
   interoperable. However, most transport and application-layer protocols
   need little or no change to operate over IPv6; exceptions are application
   protocols that embed Internet-layer addresses, such as File Transfer
   Protocol (FTP) and Network Time Protocol (NTP), where the new address
   format may cause conflicts with existing protocol syntax.

  Larger address spaceEdit

   The main advantage of IPv6 over IPv4 is its larger address space. The size
   of an IPv6 address is 128 bits, compared to 32 bits in IPv4.^[2] The
   address space therefore has 2^128 =
   340,282,366,920,938,463,463,374,607,431,768,211,456 addresses
   (approximately 3.4×10^38). Some blocks of this space and some specific
   addresses are reserved for special uses.

   While this address space is very large, it was not the intent of the
   designers of IPv6 to assure geographical saturation with usable addresses.
   Rather, the longer addresses simplify allocation of addresses, enable
   efficient route aggregation, and allow implementation of special
   addressing features. In IPv4, complex Classless Inter-Domain Routing
   (CIDR) methods were developed to make the best use of the small address
   space. The standard size of a subnet in IPv6 is 2^64 addresses, about four
   billion times the size of the entire IPv4 address space. Thus, actual
   address space utilization will be small in IPv6, but network management
   and routing efficiency are improved by the large subnet space and
   hierarchical route aggregation.

  MulticastingEdit

   [IMG] 
   Enlarge
   Multicast structure in IPv6

   Multicasting, the transmission of a packet to multiple destinations in a
   single send operation, is part of the base specification in IPv6. In IPv4
   this is an optional (although commonly implemented) feature.^[15] IPv6
   multicast addressing has features and protocols in common with IPv4
   multicast, but also provides changes and improvements by eliminating the
   need for certain protocols. IPv6 does not implement traditional IP
   broadcast, i.e. the transmission of a packet to all hosts on the attached
   link using a special broadcast address, and therefore does not define
   broadcast addresses. In IPv6, the same result is achieved by sending a
   packet to the link-local all nodes multicast group at address ff02::1,
   which is analogous to IPv4 multicasting to address 224.0.0.1. IPv6 also
   provides for new multicast implementations, including embedding rendezvous
   point addresses in an IPv6 multicast group address, which simplifies the
   deployment of inter-domain solutions.^[16]

   In IPv4 it is very difficult for an organization to get even one globally
   routable multicast group assignment, and the implementation of
   inter-domain solutions is arcane.^[17] Unicast address assignments by a
   local Internet registry for IPv6 have at least a 64-bit routing prefix,
   yielding the smallest subnet size available in IPv6 (also 64 bits). With
   such an assignment it is possible to embed the unicast address prefix into
   the IPv6 multicast address format, while still providing a 32-bit block,
   the least significant bits of the address, or approximately 4.2 billion
   multicast group identifiers. Thus each user of an IPv6 subnet
   automatically has available a set of globally routable source-specific
   multicast groups for multicast applications.^[18]

  Stateless address autoconfiguration (SLAAC)Edit

   Link: mw-deduplicated-inline-style
   See also: IPv6 address § Stateless address autoconfiguration

   IPv6 hosts configure themselves automatically. Every interface has a
   self-generated link-local address and, when connected to a network,
   conflict resolution is performed and routers provide network prefixes via
   router advertisements.^[19] Stateless configuration of routers can be
   achieved with a special router renumbering protocol.^[20] When necessary,
   hosts may configure additional stateful addresses via Dynamic Host
   Configuration Protocol version 6 (DHCPv6) or static addresses manually.

   Like IPv4, IPv6 supports globally unique IP addresses. The design of IPv6
   intended to re-emphasize the end-to-end principle of network design that
   was originally conceived during the establishment of the early Internet by
   rendering network address translation obsolete. Therefore, every device on
   the network is globally addressable directly from any other device.

   A stable, unique, globally addressable IP address would facilitate
   tracking a device across networks. Therefore, such addresses are a
   particular privacy concern for mobile devices, such as laptops and cell
   phones.^[21] To address these privacy concerns, the SLAAC protocol
   includes what are typically called "privacy addresses" or, more correctly,
   "temporary addresses", codified in RFC 4941, "Privacy Extensions for
   Stateless Address Autoconfiguration in IPv6".^[22] Temporary addresses are
   random and unstable. A typical consumer device generates a new temporary
   address daily and will ignore traffic addressed to an old address after
   one week. Temporary addresses are used by default by Windows since XP
   SP1,^[23] macOS since (Mac OS X) 10.7, Android since 4.0, and iOS since
   version 4.3. Use of temporary addresses by Linux distributions
   varies.^[24]

   Renumbering an existing network for a new connectivity provider with
   different routing prefixes is a major effort with IPv4.^[25]^[26] With
   IPv6, however, changing the prefix announced by a few routers can in
   principle renumber an entire network, since the host identifiers (the
   least-significant 64 bits of an address) can be independently
   self-configured by a host.^[19]

   The SLAAC address generation method is implementation-dependent. IETF
   recommends that addresses be deterministic but semantically opaque.^[27]

  IPsecEdit

   Internet Protocol Security (IPsec) was originally developed for IPv6, but
   found widespread deployment first in IPv4, for which it was re-engineered.
   IPsec was a mandatory part of all IPv6 protocol implementations,^[2] and
   Internet Key Exchange (IKE) was recommended, but with RFC 6434 the
   inclusion of IPsec in IPv6 implementations was downgraded to a
   recommendation because it was considered impractical to require full IPsec
   implementation for all types of devices that may use IPv6. However, as of
   RFC 4301 IPv6 protocol implementations that do implement IPsec need to
   implement IKEv2 and need to support a minimum set of cryptographic
   algorithms. This requirement will help to make IPsec implementations more
   interoperable between devices from different vendors. The IPsec
   Authentication Header (AH) and the Encapsulating Security Payload header
   (ESP) are implemented as IPv6 extension headers.^[28]

  Simplified processing by routersEdit

   The packet header in IPv6 is simpler than the IPv4 header. Many rarely
   used fields have been moved to optional header extensions.^[29] With the
   simplified IPv6 packet header the process of packet forwarding by routers
   has been simplified. Although IPv6 packet headers are at least twice the
   size of IPv4 packet headers, processing of packets that only contain the
   base IPv6 header by routers may, in some cases, be more efficient, because
   less processing is required in routers due to the headers being aligned to
   match common word sizes.^[2]^[14] However, many devices implement IPv6
   support in software (as opposed to hardware), thus resulting in very bad
   packet processing performance.^[30] Additionally, for many
   implementations, the use of Extension Headers causes packets to be
   processed by a router's CPU, leading to poor performance or even security
   issues.^[31]

   Moreover, an IPv6 header does not include a checksum. The IPv4 header
   checksum is calculated for the IPv4 header, and has to be recalculated by
   routers every time the time to live (called hop limit in the IPv6
   protocol) is reduced by one. The absence of a checksum in the IPv6 header
   furthers the end-to-end principle of Internet design, which envisioned
   that most processing in the network occurs in the leaf nodes. Integrity
   protection for the data that is encapsulated in the IPv6 packet is assumed
   to be assured by both the link layer or error detection in higher-layer
   protocols, namely the Transmission Control Protocol (TCP) and the User
   Datagram Protocol (UDP) on the transport layer. Thus, while IPv4 allowed
   UDP datagram headers to have no checksum (indicated by 0 in the header
   field), IPv6 requires a checksum in UDP headers.

   IPv6 routers do not perform IP fragmentation. IPv6 hosts are required
   either to perform path MTU discovery, perform end-to-end fragmentation, or
   send packets no larger than the default maximum transmission unit (MTU),
   which is 1280 octets.

  MobilityEdit

   Unlike mobile IPv4, mobile IPv6 avoids triangular routing and is therefore
   as efficient as native IPv6. IPv6 routers may also allow entire subnets to
   move to a new router connection point without renumbering.^[32]

  Extension headersEdit

   [IMG] 
   Enlarge
   Several examples of IPv6 extension headers

   The IPv6 packet header has a minimum size of 40 octets (320 bits). Options
   are implemented as extensions. This provides the opportunity to extend the
   protocol in the future without affecting the core packet structure.^[2]
   However, RFC 7872 notes that some network operators drop IPv6 packets with
   extension headers when they traverse transit autonomous systems.

    JumbogramsEdit

   IPv4 limits packets to 65,535 (2^16−1) octets of payload. An IPv6 node can
   optionally handle packets over this limit, referred to as jumbograms,
   which can be as large as 4,294,967,295 (2^32−1) octets. The use of
   jumbograms may improve performance over high-MTU links. The use of
   jumbograms is indicated by the Jumbo Payload Option extension header.^[33]

IPv6 packetsEdit

   Link: mw-deduplicated-inline-style
   Main article: IPv6 packet
   [IMG] 
   Enlarge
   IPv6 packet header

   An IPv6 packet has two parts: a header and payload.

   The header consists of a fixed portion with minimal functionality required
   for all packets and may be followed by optional extensions to implement
   special features.

   The fixed header occupies the first 40 octets (320 bits) of the IPv6
   packet. It contains the source and destination addresses, traffic class,
   hop count, and the type of the optional extension or payload which follows
   the header. This Next Header field tells the receiver how to interpret the
   data which follows the header. If the packet contains options, this field
   contains the option type of the next option. The "Next Header" field of
   the last option points to the upper-layer protocol that is carried in the
   packet's payload.

   The current use of the IPv6 Traffic Class field divides this between a 6
   bit Differentiated Services Code Point^[34] and a 2-bit Explicit
   Congestion Notification field.^[35]

   Extension headers carry options that are used for special treatment of a
   packet in the network, e.g., for routing, fragmentation, and for security
   using the IPsec framework.

   Without special options, a payload must be less than 64kB. With a Jumbo
   Payload option (in a Hop-By-Hop Options extension header), the payload
   must be less than 4 GB.

   Unlike with IPv4, routers never fragment a packet. Hosts are expected to
   use Path MTU Discovery to make their packets small enough to reach the
   destination without needing to be fragmented. See IPv6 packet
   fragmentation.

AddressingEdit

   Link: mw-deduplicated-inline-style
   Main article: IPv6 address
   [IMG] 
   Enlarge
   A general structure for an IPv6 unicast address

   IPv6 addresses have 128 bits. The design of the IPv6 address space
   implements a different design philosophy than in IPv4, in which subnetting
   was used to improve the efficiency of utilization of the small address
   space. In IPv6, the address space is deemed large enough for the
   foreseeable future, and a local area subnet always uses 64 bits for the
   host portion of the address, designated as the interface identifier, while
   the most-significant 64 bits are used as the routing prefix.^[36] While
   the myth has existed regarding IPv6 subnets being impossible to scan, RFC
   7707 notes that patterns resulting from some IPv6 address configuration
   techniques and algorithms allow address scanning in many real-world
   scenarios.

  Address representationEdit

   The 128 bits of an IPv6 address are represented in 8 groups of 16 bits
   each. Each group is written as four hexadecimal digits (sometimes called
   hextets^[37]^[38] or more formally hexadectets^[39] and informally a
   quibble or quad-nibble^[39]) and the groups are separated by colons (:).
   An example of this representation is
   2001:0db8:0000:0000:0000:ff00:0042:8329.

   For convenience and clarity, the representation of an IPv6 address may be
   shortened with the following rules.

     * One or more leading zeros from any group of hexadecimal digits are
       removed, which is usually done to all of the leading zeros. For
       example, the group 0042 is converted to 42.
     * Consecutive sections of zeros are replaced with two colons (::). This
       may only be used once in an address, as multiple use would render the
       address indeterminate.
       Link: mw-deduplicated-inline-style
       RFC 5952 requires that a double colon not be used to denote an omitted
       single section of zeros.^[40]

   An example of application of these rules:

           Initial address: 2001:0db8:0000:0000:0000:ff00:0042:8329.
           After removing all leading zeros in each group:
           2001:db8:0:0:0:ff00:42:8329.
           After omitting consecutive sections of zeros:
           2001:db8::ff00:42:8329.

   The loopback address 0000:0000:0000:0000:0000:0000:0000:0001 is defined in
   Link: mw-deduplicated-inline-style
   RFC 5156 and is abbreviated to ::1 by using both rules.

   As an IPv6 address may have more than one representation, the IETF has
   issued a proposed standard for representing them in text.^[41]

   Because IPv6 addresses contain colons, and URLs use colons to separate the
   host from the port number, RFC2732^[42] specifies that an IPv6 address
   used as the host-part of a URL should be enclosed in square brackets, e.g.
   http://[2001:db8:4006:812::200e] or
   http://[2001:db8:4006:812::200e]:8080/path/page.html.

  Link-local addressEdit

   [IMG] 
   Enlarge
   The Link-Local Unicast Address structure in IPv6

   All interfaces of IPv6 hosts require a link-local address, which have the
   prefix fe80::/10. This prefix is combined with a 64-bit suffix, which the
   host can compute and assign by itself without the presence or cooperation
   of an external network component like a DHCP server, in a process called
   link-local address autoconfiguration.^[citation needed]

   The lower 64 bits of the link-local address (the suffix) were originally
   derived from the MAC address of the underlying network interface card. As
   this method of assigning addresses would cause undesirable address changes
   when faulty network cards were replaced, and as it also suffered from a
   number of security and privacy issues, RFC 8064 has replaced the original
   MAC-based method with the hash-based method specified in RFC
   7217.^[citation needed]

  Address uniqueness and router solicitationEdit

   IPv6 uses a new mechanism for mapping IP addresses to link-layer addresses
   (MAC addresses), because it does not support the broadcast addressing
   method, on which the functionality of the Address Resolution Protocol
   (ARP) in IPv4 is based. IPv6 implements the Neighbor Discovery Protocol
   (NDP, ND) in the link layer, which relies on ICMPv6 and multicast
   transmission.^[5]^: 210  IPv6 hosts verify the uniqueness of their IPv6
   addresses in a local area network (LAN) by sending a neighbor solicitation
   message asking for the link-layer address of the IP address. If any other
   host in the LAN is using that address, it responds.^[43]

   A host bringing up a new IPv6 interface first generates a unique
   link-local address using one of several mechanisms designed to generate a
   unique address. Should a non-unique address be detected, the host can try
   again with a newly generated address. Once a unique link-local address is
   established, the IPv6 host determines whether the LAN is connected on this
   link to any router interface that supports IPv6. It does so by sending out
   an ICMPv6 router solicitation message to the all-routers^[44] multicast
   group with its link-local address as source. If there is no answer after a
   predetermined number of attempts, the host concludes that no routers are
   connected. If it does get a response, known as a router advertisement,
   from a router, the response includes the network configuration information
   to allow establishment of a globally unique address with an appropriate
   unicast network prefix.^[45] There are also two flag bits that tell the
   host whether it should use DHCP to get further information and addresses:

     * The Manage bit, which indicates whether or not the host should use
       DHCP to obtain additional addresses rather than rely on an
       auto-configured address from the router advertisement.
     * The Other bit, which indicates whether or not the host should obtain
       other information through DHCP. The other information consists of one
       or more prefix information options for the subnets that the host is
       attached to, a lifetime for the prefix, and two flags:^[43]
          * On-link: If this flag is set, the host will treat all addresses
            on the specific subnet as being on-link and send packets directly
            to them instead of sending them to a router for the duration of
            the given lifetime.
          * Address: This flag tells the host to actually create a global
            address.

  Global addressingEdit

   [IMG] 
   Enlarge
   The global unicast address structure in IPv6

   The assignment procedure for global addresses is similar to local-address
   construction. The prefix is supplied from router advertisements on the
   network. Multiple prefix announcements cause multiple addresses to be
   configured.^[43]

   Stateless address autoconfiguration (SLAAC) requires a /64 address block,
   as defined in
   Link: mw-deduplicated-inline-style
   RFC 4291. Local Internet registries are assigned at least /32 blocks,
   which they divide among subordinate networks.^[46] The initial
   recommendation stated assignment of a /48 subnet to end-consumer sites (
   Link: mw-deduplicated-inline-style
   RFC 3177). This was replaced by
   Link: mw-deduplicated-inline-style
   RFC 6177, which "recommends giving home sites significantly more than a
   single /64, but does not recommend that every home site be given a /48
   either". /56s are specifically considered. It remains to be seen whether
   ISPs will honor this recommendation. For example, during initial trials,
   Comcast customers were given a single /64 network.^[47]

IPv6 in the Domain Name SystemEdit

   In the Domain Name System (DNS), hostnames are mapped to IPv6 addresses by
   AAAA ("quad-A") resource records. For reverse resolution, the IETF
   reserved the domain ip6.arpa, where the name space is hierarchically
   divided by the 1-digit hexadecimal representation of nibble units (4 bits)
   of the IPv6 address. This scheme is defined in
   Link: mw-deduplicated-inline-style
   RFC 3596.

   When a dual-stack host queries a DNS server to resolve a fully qualified
   domain name (FQDN), the DNS client of the host sends two DNS requests, one
   querying A records and the other querying AAAA records. The host operating
   system may be configured with a preference for address selection rules
   Link: mw-deduplicated-inline-style
   RFC 6724.^[48]

   An alternate record type was used in early DNS implementations for IPv6,
   designed to facilitate network renumbering, the A6 records for the forward
   lookup and a number of other innovations such as bit-string labels and
   DNAME records. It is defined in
   Link: mw-deduplicated-inline-style
   RFC 2874 and its references (with further discussion of the pros and cons
   of both schemes in
   Link: mw-deduplicated-inline-style
   RFC 3364), but has been deprecated to experimental status (
   Link: mw-deduplicated-inline-style
   RFC 3363).

Transition mechanismsEdit

   Link: mw-deduplicated-inline-style
   Main article: IPv6 transition mechanism

   IPv6 is not foreseen to supplant IPv4 instantaneously. Both protocols will
   continue to operate simultaneously for some time. Therefore, IPv6
   transition mechanisms are needed to enable IPv6 hosts to reach IPv4
   services and to allow isolated IPv6 hosts and networks to reach each other
   over IPv4 infrastructure.^[49]

   According to Silvia Hagen, a dual-stack implementation of the IPv4 and
   IPv6 on devices is the easiest way to migrate to IPv6.^[50] Many other
   transition mechanisms use tunneling to encapsulate IPv6 traffic within
   IPv4 networks and vice versa. This is an imperfect solution, which reduces
   the maximum transmission unit (MTU) of a link and therefore complicates
   Path MTU Discovery, and may increase latency.^[51]^[52]

  Dual-stack IP implementationEdit

   Dual-stack IP implementations provide complete IPv4 and IPv6 protocol
   stacks in the operating system of a computer or network device on top of
   the common physical layer implementation, such as Ethernet. This permits
   dual-stack hosts to participate in IPv6 and IPv4 networks simultaneously.
   The method is defined in
   Link: mw-deduplicated-inline-style
   RFC 4213.^[53]

   A device with dual-stack implementation in the operating system has an
   IPv4 and IPv6 address, and can communicate with other nodes in the LAN or
   the Internet using either IPv4 or IPv6. The Domain Name System (DNS)
   protocol is used by both IP protocols to resolve fully qualified domain
   names (FQDN) and IP addresses, but dual stack requires that the resolving
   DNS server can resolve both types of addresses. Such a dual stack DNS
   server would hold IPv4 addresses in the A records, and IPv6 addresses in
   the AAAA records. Depending on the destination that is to be resolved, a
   DNS name server may return an IPv4 or IPv6 IP address, or both. A default
   address selection mechanism, or preferred protocol, needs to be configured
   either on hosts or the DNS server. The IETF has published Happy Eyeballs
   to assist dual stack applications, so that they can connect using both
   IPv4 and IPv6, but prefer an IPv6 connection if it is available. However,
   dual-stack also needs to be implemented on all routers between the host
   and the service for which the DNS server has returned an IPv6 address.
   Dual-stack clients should only be configured to prefer IPv6, if the
   network is able to forward IPv6 packets using the IPv6 versions of routing
   protocols. When dual stack networks protocols are in place the application
   layer can be migrated to IPv6.^[54]

   While dual-stack is supported by major operating system and network device
   vendors, legacy networking hardware and servers don't support IPv6.

  ISP customers with public-facing IPv6Edit

   [IMG] 
   Enlarge
   IPv6 Prefix Assignment mechanism with IANA, RIRs, and ISPs

   Internet service providers (ISPs) are increasingly providing their
   business and private customers with public-facing IPv6 global unicast
   addresses. If IPv4 is still used in the local area network (LAN), however,
   and the ISP can only provide one public-facing IPv6 address, the IPv4 LAN
   addresses are translated into the public facing IPv6 address using NAT64,
   a network address translation (NAT) mechanism. Some ISPs cannot provide
   their customers with public-facing IPv4 and IPv6 addresses, thus
   supporting dual-stack networking, because some ISPs have exhausted their
   globally routable IPv4 address pool. Meanwhile, ISP customers are still
   trying to reach IPv4 web servers and other destinations.^[55]

   A significant percentage of ISPs in all regional Internet registry (RIR)
   zones have obtained IPv6 address space. This includes many of the world's
   major ISPs and mobile network operators, such as Verizon Wireless, StarHub
   Cable, Chubu Telecommunications, Kabel Deutschland, Swisscom, T-Mobile,
   Internode and Telefónica.^[56]

   While some ISPs still allocate customers only IPv4 addresses, many ISPs
   allocate their customers only an IPv6 or dual-stack IPv4 and IPv6. ISPs
   report the share of IPv6 traffic from customers over their network to be
   anything between 20% and 40%, but by mid-2017 IPv6 traffic still only
   accounted for a fraction of total traffic at several large Internet
   exchange points (IXPs). AMS-IX reported it to be 2% and SeattleIX reported
   7%. A 2017 survey found that many DSL customers that were served by a dual
   stack ISP did not request DNS servers to resolve fully qualified domain
   names into IPv6 addresses. The survey also found that the majority of
   traffic from IPv6-ready web-server resources were still requested and
   served over IPv4, mostly due to ISP customers that did not use the dual
   stack facility provided by their ISP and to a lesser extent due to
   customers of IPv4-only ISPs.^[57]

  TunnelingEdit

   The technical basis for tunneling, or encapsulating IPv6 packets in IPv4
   packets, is outlined in RFC 4213. When the Internet backbone was
   IPv4-only, one of the frequently used tunneling protocols was 6to4.^[58]
   Teredo tunneling was also frequently used for integrating IPv6 LANs with
   the IPv4 Internet backbone. Teredo is outlined in RFC 4380 and allows IPv6
   local area networks to tunnel over IPv4 networks, by encapsulating IPv6
   packets within UDP. The Teredo relay is an IPv6 router that mediates
   between a Teredo server and the native IPv6 network. It was expected that
   6to4 and Teredo would be widely deployed until ISP networks would switch
   to native IPv6, but by 2014 Google Statistics showed that the use of both
   mechanisms had dropped to almost 0.^[59]

  IPv4-mapped IPv6 addressesEdit

   [IMG] 
   Enlarge
   IPv4-compatible IPv6 unicast address
   [IMG] 
   Enlarge
   IPv4-mapped IPv6 unicast address

   Hybrid dual-stack IPv6/IPv4 implementations recognize a special class of
   addresses, the IPv4-mapped IPv6 addresses.^[60]^[61] These addresses are
   typically written with a 96-bit prefix in the standard IPv6 format, and
   the remaining 32 bits are written in the customary dot-decimal notation of
   IPv4.

   Addresses in this group consist of an 80-bit prefix of zeros, the next 16
   bits are ones, and the remaining, least-significant 32 bits contain the
   IPv4 address. For example, ::ffff:192.0.2.128 represents the IPv4 address
   192.0.2.128. A previous format, called "IPv4-compatible IPv6 address", was
   ::192.0.2.128; however, this method is deprecated.^[61]

   Because of the significant internal differences between IPv4 and IPv6
   protocol stacks, some of the lower-level functionality available to
   programmers in the IPv6 stack does not work the same when used with
   IPv4-mapped addresses. Some common IPv6 stacks do not implement the
   IPv4-mapped address feature, either because the IPv6 and IPv4 stacks are
   separate implementations (e.g., Microsoft Windows 2000, XP, and Server
   2003), or because of security concerns (OpenBSD).^[62] On these operating
   systems, a program must open a separate socket for each IP protocol it
   uses. On some systems, e.g., the Linux kernel, NetBSD, and FreeBSD, this
   feature is controlled by the socket option IPV6_V6ONLY.^[63]^: 22 

   The address prefix 64:ff9b::/96 is a class of IPv4-embedded IPv6 addresses
   for use in NAT64 transition methods.^[64] For example,
   64:ff9b::192.0.2.128 represents the IPv4 address 192.0.2.128.

SecurityEdit

   A number of security implications may arise from the use of IPv6. Some of
   them may be related with the IPv6 protocols themselves, while others may
   be related with implementation flaws.^[65]^[66]

  Shadow networksEdit

   The addition of nodes having IPv6 enabled by default by the software
   manufacturer, may result in the inadvertent creation of shadow networks,
   causing IPv6 traffic flowing into networks having only IPv4 security
   management in place. This may also occur with operating system upgrades,
   when the newer operating system enables IPv6 by default, while the older
   one did not. Failing to update the security infrastructure to accommodate
   IPv6 can lead to IPv6 traffic bypassing it.^[67] Shadow networks have
   occurred on business networks in which enterprises are replacing Windows
   XP systems that do not have an IPv6 stack enabled by default, with Windows
   7 systems, that do.^[68] Some IPv6 stack implementors have therefore
   recommended disabling IPv4 mapped addresses and instead using a dual-stack
   network where supporting both IPv4 and IPv6 is necessary.^[69]

  IPv6 packet fragmentationEdit

   Research has shown that the use of fragmentation can be leveraged to evade
   network security controls, similar to IPv4. As a result,
   Link: mw-deduplicated-inline-style
   RFC 7112 requires that the first fragment of an IPv6 packet contains the
   entire IPv6 header chain, such that some very pathological fragmentation
   cases are forbidden. Additionally, as a result of research on the evasion
   of RA-Guard in
   Link: mw-deduplicated-inline-style
   RFC 7113,
   Link: mw-deduplicated-inline-style
   RFC 6980 has deprecated the use of fragmentation with Neighbor Discovery,
   and discouraged the use of fragmentation with Secure Neighbor Discovery
   (SEND).

Standardization through RFCsEdit

  Working-group proposalsEdit

   [IMG] 
   Enlarge
   A timeline for the standards governing IPv6

   Due to the anticipated global growth of the Internet, the Internet
   Engineering Task Force (IETF) in the early 1990s started an effort to
   develop a next generation IP protocol.^[5]^: 209  By the beginning of
   1992, several proposals appeared for an expanded Internet addressing
   system and by the end of 1992 the IETF announced a call for white
   papers.^[70] In September 1993, the IETF created a temporary, ad hoc IP
   Next Generation (IPng) area to deal specifically with such issues. The new
   area was led by Allison Mankin and Scott Bradner, and had a directorate
   with 15 engineers from diverse backgrounds for direction-setting and
   preliminary document review:^[7]^[71] The working-group members were J.
   Allard (Microsoft), Steve Bellovin (AT&T), Jim Bound (Digital Equipment
   Corporation), Ross Callon (Wellfleet), Brian Carpenter (CERN), Dave Clark
   (MIT), John Curran (NEARNET), Steve Deering (Xerox), Dino Farinacci
   (Cisco), Paul Francis (NTT), Eric Fleischmann (Boeing), Mark Knopper
   (Ameritech), Greg Minshall (Novell), Rob Ullmann (Lotus), and Lixia Zhang
   (Xerox).^[72]

   The Internet Engineering Task Force adopted the IPng model on 25 July
   1994, with the formation of several IPng working groups.^[7] By 1996, a
   series of RFCs was released defining Internet Protocol version 6 (IPv6),
   starting with
   Link: mw-deduplicated-inline-style
   RFC 1883. (Version 5 was used by the experimental Internet Stream
   Protocol.)

  RFC standardizationEdit

   The first RFC to standardize IPv6 was the
   Link: mw-deduplicated-inline-style
   RFC 1883 in 1995, which became obsoleted by
   Link: mw-deduplicated-inline-style
   RFC 2460 in 1998.^[5]^: 209  In July 2017 this RFC was superseded by
   Link: mw-deduplicated-inline-style
   RFC 8200, which elevated IPv6 to "Internet Standard" (the highest maturity
   level for IETF protocols).^[3]

DeploymentEdit

   Link: mw-deduplicated-inline-style
   Main article: IPv6 deployment
   [IMG] 
   Enlarge
   Monthly IPv6 allocations per regional Internet registry (RIR)

   The 1993 introduction of Classless Inter-Domain Routing (CIDR) in the
   routing and IP address allocation for the Internet, and the extensive use
   of network address translation (NAT), delayed IPv4 address exhaustion to
   allow for IPv6 deployment, which began in the mid-2000s.

   Universities were among the early adopters of IPv6. Virginia Tech deployed
   IPv6 at a trial location in 2004 and later expanded IPv6 deployment across
   the campus network. By 2016, 82% of the traffic on their network used
   IPv6. Imperial College London began experimental IPv6 deployment in 2003
   and by 2016 the IPv6 traffic on their networks averaged between 20% and
   40%. A significant portion of this IPv6 traffic was generated through
   their high energy physics collaboration with CERN, which relies entirely
   on IPv6.^[73]

   The Domain Name System (DNS) has supported IPv6 since 2008. In the same
   year, IPv6 was first used in a major world event during the Beijing 2008
   Summer Olympics.^[74]^[75]

   By 2011, all major operating systems in use on personal computers and
   server systems had production-quality IPv6 implementations. Cellular
   telephone systems presented a large deployment field for Internet Protocol
   devices as mobile telephone service made the transition from 3G to 4G
   technologies, in which voice is provisioned as a voice over IP (VoIP)
   service that would leverage IPv6 enhancements. In 2009, the US cellular
   operator Verizon released technical specifications for devices to operate
   on its "next-generation" networks.^[76] The specification mandated IPv6
   operation according to the 3GPP Release 8 Specifications (March 2009), and
   deprecated IPv4 as an optional capability.^[76]

   The deployment of IPv6 in the Internet backbone continued. In 2018 only
   25.3% of the about 54,000 autonomous systems advertised both IPv4 and IPv6
   prefixes in the global Border Gateway Protocol (BGP) routing database. A
   further 243 networks advertised only an IPv6 prefix. Internet backbone
   transit networks offering IPv6 support existed in every country globally,
   except in parts of Africa, the Middle East and China.^[77]^: 6  By
   mid-2018 some major European broadband ISPs had deployed IPv6 for the
   majority of their customers. Sky UK provided over 86% of its customers
   with IPv6, Deutsche Telekom had 56% deployment of IPv6, XS4ALL in the
   Netherlands had 73% deployment and in Belgium the broadband ISPs VOO and
   Telenet had 73% and 63% IPv6 deployment respectively.^[77]^: 7  In the
   United States the broadband ISP Comcast had an IPv6 deployment of about
   66%. In 2018 Comcast reported an estimated 36.1 million IPv6 users, while
   AT&T reported 22.3 million IPv6 users.^[77]^: 7–8 

See alsoEdit

     * icon Internet portal
     * China Next Generation Internet
     * Comparison of IPv6 support in operating systems
     * Comparison of IPv6 support in common applications
     * DoD IPv6 product certification
     * List of IPv6 tunnel brokers
     * University of New Hampshire InterOperability Laboratory

ReferencesEdit

    1. ^
       Link: mw-deduplicated-inline-style
       "FAQs". New Zealand IPv6 Task Force. Archived from the original on 29
       January 2019. Retrieved 26 October 2015.
    2. ^ ^a ^b ^c ^d ^e ^f
       Link: mw-deduplicated-inline-style
       S. Deering; R. Hinden (December 1998), Internet Protocol, Version 6
       (IPv6) Specification, Internet Engineering Task Force (IETF), RFC 2460
       Obsoletes RFC 1883.
    3. ^ ^a ^b
       Link: mw-deduplicated-inline-style
       S. Deering; R. Hinden (July 2017), "Internet Protocol, Version 6
       (IPv6) Specification", Ietf Request for Comments (RFC) Pages - Test,
       Internet Engineering Task Force (IETF), ISSN 2070-1721, RFC 8200
       Obsoletes RFC 2460.
    4. ^
       Link: mw-deduplicated-inline-style
       Siddiqui, Aftab (17 July 2017). "RFC 8200 – IPv6 Has Been
       Standardized". Internet Society. Retrieved 25 February 2018.
    5. ^ ^a ^b ^c ^d
       Link: mw-deduplicated-inline-style
       Rosen, Rami (2014). Linux Kernel Networking: Implementation and
       Theory. New York: Apress. ISBN 9781430261971. OCLC 869747983.
    6. ^
       Link: mw-deduplicated-inline-style
       Google IPv6 Conference 2008: What will the IPv6 Internet look like?.
       Event occurs at 13:35. Archived from the original on 11 December 2021.
    7. ^ ^a ^b ^c
       Link: mw-deduplicated-inline-style
       Bradner, S.; Mankin, A. (January 1995). The Recommendation for the IP
       Next Generation Protocol. IETF. doi:10.17487/RFC1752. RFC 1752.
    8. ^
       Link: mw-deduplicated-inline-style
       "Free Pool of IPv4 Address Space Depleted". NRO.net. Montevideo: The
       Number Resource Organization. 3 February 2011. Retrieved 19 January
       2022.
    9. ^
       Link: mw-deduplicated-inline-style
       Rashid, Fahmida. "IPv4 Address Exhaustion Not Instant Cause for
       Concern with IPv6 in Wings". eWeek. Retrieved 23 June 2012.^[permanent
       dead link]
   10. ^
       Link: mw-deduplicated-inline-style
       Ward, Mark (14 September 2012). "Europe hits old internet address
       limits". BBC News. BBC. Retrieved 15 September 2012.
   11. ^
       Link: mw-deduplicated-inline-style
       Huston, Geoff. "IPV4 Address Report".
   12. ^
       Link: mw-deduplicated-inline-style
       "African Network Information Center : -". my.afrinic.net. Retrieved 28
       November 2018.
   13. ^
       Link: mw-deduplicated-inline-style
       news, Publication date: 25 Nov 2019-; ipv4; Depletion, Ipv4; ipv6;
       Release, Press. "The RIPE NCC has run out of IPv4 Addresses". RIPE
       Network Coordination Centre. Retrieved 26 November 2019.
   14. ^ ^a ^b
       Link: mw-deduplicated-inline-style
       Partridge, C.; Kastenholz, F. (December 1994). "Technical Criteria for
       Choosing IP The Next Generation (IPng)". RFC 1726.
   15. ^
       Link: mw-deduplicated-inline-style
       RFC 1112, Host extensions for IP multicasting, S. Deering (August
       1989)
   16. ^
       Link: mw-deduplicated-inline-style
       RFC 3956, Embedding the Rendezvous Point (RP) Address in an IPv6
       Multicast Address, P. Savola, B. Haberman (November 2004)
   17. ^
       Link: mw-deduplicated-inline-style
       RFC 2908, The Internet Multicast Address Allocation Architecture, D.
       Thaler, M. Handley, D. Estrin (September 2000)
   18. ^
       Link: mw-deduplicated-inline-style
       RFC 3306, Unicast-Prefix-based IPv6 Multicast Addresses, B. Haberman,
       D. Thaler (August 2002)
   19. ^ ^a ^b
       Link: mw-deduplicated-inline-style
       Thomson, S.; Narten, T.; Jinmei, T. (September 2007). "IPv6 Stateless
       Address Autoconfiguration". RFC 4862.
   20. ^
       Link: mw-deduplicated-inline-style
       RFC 2894, Router Renumbering for IPv6, M. Crawford, August 2000.
   21. ^
       Link: mw-deduplicated-inline-style
       T. Narten; R. Draves; S. Krishnan (September 2007). "Privacy
       Extensions for Stateless Address Autoconfiguration in IPv6".
       www.ietf.org. Retrieved 13 March 2017.
   22. ^
       Link: mw-deduplicated-inline-style
       Narten, Thomas; Draves, Richard; Krishnan, Suresh. Privacy Extensions
       for Stateless Address Autoconfiguration in IPv6. doi:10.17487/RFC4941.
       RFC 4941.
   23. ^
       Link: mw-deduplicated-inline-style
       "Overview of the Advanced Networking Pack for Windows XP". Archived
       from the original on 7 September 2017. Retrieved 15 April 2019.
   24. ^
       Link: mw-deduplicated-inline-style
       "Privacy Extensions for IPv6 SLAAC". Internet Society. 8 August 2014.
       Retrieved 17 January 2020.
   25. ^
       Link: mw-deduplicated-inline-style
       Ferguson, P.; Berkowitz, H. (January 1997). "Network Renumbering
       Overview: Why would I want it and what is it anyway?". RFC 2071.
   26. ^
       Link: mw-deduplicated-inline-style
       Berkowitz, H. (January 1997). "Router Renumbering Guide". RFC 2072.
   27. ^
       Link: mw-deduplicated-inline-style
       Cooper, Alissa; Gont, Fernando; Thaler, Dave. Recommendation on Stable
       IPv6 Interface Identifiers. doi:10.17487/RFC8064. RFC 8064.
   28. ^
       Link: mw-deduplicated-inline-style
       Silvia Hagen (2014). IPv6 Essentials: Integrating IPv6 into Your IPv4
       Network (3rd ed.). Sebastopol, CA: O'Reilly Media. p. 196.
       ISBN 978-1-4493-3526-7. OCLC 881832733.
   29. ^
       Link: mw-deduplicated-inline-style
       "The History of Domain Names | IPv6". www.historyofdomainnames.com.
       Archived from the original on 12 June 2018. Retrieved 12 June 2018.
   30. ^
       Link: mw-deduplicated-inline-style
       Zack, E. (July 2013). "IPv6 Security Assessment and Benchmarking".
   31. ^
       Link: mw-deduplicated-inline-style
       Gont, F. (March 2016). "Operational Implications of IPv6 Packets with
       Extension Headers". draft-gont-v6ops-ipv6-ehs-packet-drops-03.
   32. ^
       Link: mw-deduplicated-inline-style
       RFC 3963, Network Mobility (NEMO) Basic Protocol Support, V.
       Devarapalli, R. Wakikawa, A. Petrescu, P. Thubert (January 2005)
   33. ^
       Link: mw-deduplicated-inline-style
       RFC 2675, IPv6 Jumbograms, D. Borman, S. Deering, R. Hinden (August
       1999)
   34. ^
       Link: mw-deduplicated-inline-style
       RFC 2474
   35. ^
       Link: mw-deduplicated-inline-style
       RFC 3168
   36. ^
       Link: mw-deduplicated-inline-style
       RFC 4291, p. 9.
   37. ^
       Link: mw-deduplicated-inline-style
       Graziani, Rick (2012). IPv6 Fundamentals: A Straightforward Approach
       to Understanding IPv6. Cisco Press. p. 55. ISBN 978-0-13-303347-2.
   38. ^
       Link: mw-deduplicated-inline-style
       Coffeen, Tom (2014). IPv6 Address Planning: Designing an Address Plan
       for the Future. O'Reilly Media. p. 170. ISBN 978-1-4919-0326-1.
   39. ^ ^a ^b
       Link: mw-deduplicated-inline-style
       Horley, Edward (2013). Practical IPv6 for Windows Administrators.
       Apress. p. 17. ISBN 978-1-4302-6371-5.
   40. ^
       Link: mw-deduplicated-inline-style
       S. Kawamura (August 2010). "A Recommendation for IPv6 Address Text
       Representation". section 4.2.2. RFC 5952.
   41. ^
       Link: mw-deduplicated-inline-style
       S. Kawamura (August 2010). "A Recommendation for IPv6 Address Text
       Representation". RFC 5952.
   42. ^
       Link: mw-deduplicated-inline-style
       "Format for Literal IPv6 Addresses in URL's". August 2010. RFC 2732.
   43. ^ ^a ^b ^c
       Link: mw-deduplicated-inline-style
       Narten, T. (August 1999). "Neighbor discovery and stateless
       autoconfiguration in IPv6". IEEE Internet Computing. 3 (4): 54–62.
       doi:10.1109/4236.780961.
   44. ^
       Link: mw-deduplicated-inline-style
       T. Narten (September 2007). "Neighbor Discovery for IP version 6
       (IPv6)". section 6.3.7. RFC 4861.
   45. ^
       Link: mw-deduplicated-inline-style
       S. Thomson (September 2007). "IPv6 Stateless Address
       Autoconfiguration". section 5.5.1. RFC 4862.
   46. ^
       Link: mw-deduplicated-inline-style
       "IPv6 Address Allocation and Assignment Policy". RIPE NCC. 8 February
       2011. Retrieved 27 March 2011.
   47. ^
       Link: mw-deduplicated-inline-style
       Brzozowski, John (31 January 2011). "Comcast Activates First Users
       With IPv6 Native Dual Stack Over DOCSIS". corporate.comcast.com.
       Comcast. Retrieved 15 April 2019.
   48. ^
       Link: mw-deduplicated-inline-style
       Silvia Hagen (2014). IPv6 Essentials: Integrating IPv6 into Your IPv4
       Network. O'Reilly Media, Inc. p. 176. ISBN 9781449335267.
   49. ^
       Link: mw-deduplicated-inline-style
       "IPv6 Transition Mechanism / Tunneling Comparison". Sixxs.net.
       Retrieved 20 January 2012.
   50. ^
       Link: mw-deduplicated-inline-style
       Silvia Hagen (2014). IPv6 Essentials: Integrating IPv6 into Your IPv4
       Network. O'Reilly Media, Inc. pp. 222–223. ISBN 9781449335267.
   51. ^
       Link: mw-deduplicated-inline-style
       "Advisory Guidelines for 6to4 Deployment". IETF. RFC 6343. Retrieved
       20 August 2012.
   52. ^
       Link: mw-deduplicated-inline-style
       "IPv6: Dual stack where you can; tunnel where you must".
       networkworld.com. 5 September 2007. Archived from the original on 11
       May 2008. Retrieved 27 November 2012.
   53. ^
       Link: mw-deduplicated-inline-style
       "Basic Transition Mechanisms for IPv6 Hosts and Routers". IETF.
       RFC 4213. Retrieved 20 August 2012.
   54. ^
       Link: mw-deduplicated-inline-style
       Silvia Hagen (2014). IPv6 Essentials: Integrating IPv6 into Your IPv4
       Network. O'Reilly Media, Inc. p. 222. ISBN 9781449335267.
   55. ^
       Link: mw-deduplicated-inline-style
       "Understanding Dual Stacking of IPv4 and IPv6 Unicast Addresses".
       Juniper.net. Juniper Networks. 31 August 2017. Retrieved 19 January
       2022.
   56. ^
       Link: mw-deduplicated-inline-style
       "IPv6". NRO.net. Retrieved 13 March 2017.
   57. ^
       Link: mw-deduplicated-inline-style
       Pujol, Enric (12 June 2017). "What Stops IPv6 Traffic in a Dual-Stack
       ISP?". APNIC.net. Retrieved 13 June 2017.
   58. ^
       Link: mw-deduplicated-inline-style
       Steven J. Vaughan-Nichols (14 October 2010). "Five ways for IPv6 and
       IPv4 to peacefully co-exist". www.zdnet.com. Retrieved 13 March 2017.
   59. ^
       Link: mw-deduplicated-inline-style
       Silvia Hagen (2014). IPv6 Essentials: Integrating IPv6 into Your IPv4
       Network. O'Reilly Media, Inc. p. 33. ISBN 9781449335267.
   60. ^
       Link: mw-deduplicated-inline-style
       M. Cotton; L. Vegoda; B. Haberman (April 2013). R. Bonica (ed.).
       Special-Purpose IP Address Registries. IETF. sec. 2.2.3.
       doi:10.17487/RFC6890. BCP 153. RFC 6890. Table 20.
   61. ^ ^a ^b
       Link: mw-deduplicated-inline-style
       R. Hinden; S. Deering (February 2006). IP Version 6 Addressing
       Architecture. Network Working Group. doi:10.17487/RFC4291. RFC 4291.
   62. ^ inet6(4) – OpenBSD Kernel Interfaces Manual
   63. ^
       Link: mw-deduplicated-inline-style
       R. Gilligan; S. Thomson; J. Bound; J. McCann; W. Stevens (February
       2003). Basic Socket Interface Extensions for IPv6. Network Working
       Group. doi:10.17487/RFC3493. RFC 3493.
   64. ^
       Link: mw-deduplicated-inline-style
       C. Bao; C. Huitema; M. Bagnulo; M. Boucadair; X. Li (October 2010).
       IPv6 Addressing of IPv4/IPv6 Translators. IETF. doi:10.17487/RFC6052.
       RFC 6052.
   65. ^
       Link: mw-deduplicated-inline-style
       Gont, Fernando (10 March 2019), IPv6 Security for IPv4 Engineers
       (PDF), retrieved 30 August 2019
   66. ^
       Link: mw-deduplicated-inline-style
       Gont, Fernando (10 January 2019), IPv6 Security Frequently Asked
       Questions (FAQ) (PDF), retrieved 30 August 2019
   67. ^
       Link: mw-deduplicated-inline-style
       Mullins, Robert (5 April 2012), Shadow Networks: an Unintended IPv6
       Side Effect, archived from the original on 11 April 2013, retrieved 2
       March 2013
   68. ^
       Link: mw-deduplicated-inline-style
       Cicileo, Guillermo; Gagliano, Roque; O’Flaherty, Christian; et al.
       (October 2009). IPv6 For All: A Guide for IPv6 Usage and Application
       in Different Environments (PDF). p. 5. Retrieved 2 March 2013.
   69. ^
       Link: mw-deduplicated-inline-style
       Jun-ichiro itojun Hagino (October 2003). "IPv4-Mapped Addresses on the
       Wire Considered Harmful".
   70. ^
       Link: mw-deduplicated-inline-style
       Bradner, S.; Mankin, A. (December 1993). "IP: Next Generation (IPng)
       White Paper Solicitation". RFC 1550.
   71. ^
       Link: mw-deduplicated-inline-style
       "History of the IPng Effort". The Sun. Archived from the original on
       23 May 2014.
   72. ^
       Link: mw-deduplicated-inline-style
       "The Recommendation for the IP Next Generation Protocol – Appendix B".
       RFC 1752.
   73. ^
       Link: mw-deduplicated-inline-style
       State of IPv6 Deployment 2018, Internet Society, 2018, p. 3
   74. ^
       Link: mw-deduplicated-inline-style
       "Beijing2008.cn leaps to next-generation Net" (Press release). The
       Beijing Organizing Committee for the Games of the XXIX Olympiad. 30
       May 2008. Archived from the original on 4 February 2009.
   75. ^
       Link: mw-deduplicated-inline-style
       Das, Kaushik (2008). "IPv6 and the 2008 Beijing Olympics". IPv6.com.
       Retrieved 15 August 2008.
   76. ^ ^a ^b
       Link: mw-deduplicated-inline-style
       Morr, Derek (9 June 2009). "Verizon Mandates IPv6 Support for Next-Gen
       Cell Phones". CircleID.
   77. ^ ^a ^b ^c
       Link: mw-deduplicated-inline-style
       "State of IPv6 Deployment 2018" (PDF). InternetSociety.org. Internet
       Society. Retrieved 19 January 2022.

External linksEdit

   Wikiversity has learning resources about IPv6 

   Look up IPv6 in Wiktionary, the free dictionary. 

     * IPv6 in the Linux Kernel by Rami Rosen
     * An Introduction and Statistics about IPv6 by Google
     * The standard document ratifying IPv6 – RFC 8200 document ratifying
       IPv6 as an Internet Standard
   Retrieved from
   "https://en.wikipedia.org/w/index.php?title=IPv6&oldid=1080648470"
   Last edited on 2 April 2022, at 15:03
   Wikipedia
     * This page was last edited on 2 April 2022, at 15:03 (UTC).
     * Content is available under CC BY-SA 3.0 unless otherwise noted.
     * Privacy policy
     * About Wikipedia
     * Disclaimers
     * Contact Wikipedia
     * Terms of Use
     * Desktop
     * Developers
     * Statistics
     * Cookie statement
