



Internet Engineering Task Force (IETF)                        L. Colitti
Request for Comments: 9762                                    J. Linkova
Updates: 4861, 4862                                           X. Ma, Ed.
Category: Standards Track                                         Google
ISSN: 2070-1721                                             D. Lamparter
                                                            NetDEF, Inc.
                                                               June 2025


Using Router Advertisements to Signal the Availability of DHCPv6 Prefix
                         Delegation to Clients

Abstract

   This document defines the P flag in the Prefix Information Option
   (PIO) of IPv6 Router Advertisements (RAs).  The flag is used to
   indicate that the network prefers that clients use the deployment
   model in RFC 9663 instead of using individual addresses in the on-
   link prefix assigned using Stateless Address Autoconfiguration
   (SLAAC) or DHCPv6 address assignment.

   This document updates RFC 4862 to indicate that the Autonomous flag
   in a PIO needs to be ignored if the PIO has the P flag set.  It also
   updates RFC 4861 to specify that the P flag indicates DHCPv6 prefix
   delegation support for clients.

Status of This Memo

   This is an Internet Standards Track document.

   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).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc9762.

Copyright Notice

   Copyright (c) 2025 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
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   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
   include Revised BSD License text as described in Section 4.e of the
   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
   2.  Requirements Language
   3.  Terminology
   4.  Rationale
   5.  P Flag Overview
   6.  Router Behavior
   7.  Client Behavior
     7.1.  Processing the P Flag
     7.2.  Using Delegated Prefix(es)
     7.3.  Absence of PIOs with the P Bit Set
     7.4.  On-Link Communication
     7.5.  Source Address Selection
   8.  Multihoming
   9.  Modifications to RFC-Mandated Behavior
     9.1.  Changes to RFC 4861
     9.2.  Changes to RFC 4862
   10. Security Considerations
   11. Privacy Considerations
   12. IANA Considerations
   13. References
     13.1.  Normative References
     13.2.  Informative References
   Acknowledgements
   Authors' Addresses

1.  Introduction

   [RFC9663] documents an IPv6 address assignment model where IPv6
   devices obtain dedicated prefixes from the network via DHCPv6 prefix
   delegation (DHCPv6-PD) [RFC8415].  This model provides devices with a
   large IPv6 address space they can use to create addresses for
   communication, individually number virtual machines (VMs) or
   containers, or extend the network to downstream devices.  It also
   provides scalability benefits on large networks because network
   infrastructure devices do not need to maintain per-address state,
   such as IPv6 neighbor cache, Source Address Validation Improvement
   (SAVI) [RFC7039] mappings, Virtual eXtensible Local Area Network
   (VXLAN) [RFC7348] routes, etc.

   On networks with fewer devices, however, this model may not be
   appropriate, because scaling to support multiple individual IPv6
   addresses per device is less of a concern.  Also, many home networks
   currently offer prefix delegation but assume that a limited number of
   specialized devices and/or applications will require delegated
   prefixes and thus do not allocate enough address space to offer
   prefixes to every device that connects to the network.  For example,
   if clients assume the [RFC9663] deployment model on a home network
   that only receives a /60 from the ISP and each client obtains a /64
   prefix, then the network will run out of prefixes after 15 devices
   have been connected.

   Therefore, to safely roll out the support of the deployment model
   defined in [RFC9663] on the client side, it is necessary to have a
   mechanism for the network to signal to the client which address
   assignment method is preferred.


2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  Terminology

   Node:  a device that implements IPv6 [RFC8200]

   Host:  any node that is not a router [RFC8200]

   Client:  a node that connects to a network and acquires addresses.
      The node may wish to obtain addresses for its own use, or it may
      be a router that wishes to extend the network to its physical or
      virtual subsystems, or both.  It may be either a host or a router
      as defined by [RFC8200].

   DHCPv6-PD:  DHCPv6 Prefix Delegation [RFC8415]; a mechanism to
      delegate IPv6 prefixes to clients.

   DHCPv6 IA_NA:  Identity Association for Non-temporary Addresses
      (Section 21.4 of [RFC8415])

   DHCPv6 IA_PD:  Identity Association for Prefix Delegation
      (Section 21.21 of [RFC8415])

   ND:  Neighbor Discovery [RFC4861]

   On-link address:  an address that is assigned to an interface on a
      specified link [RFC4861]

   On-link prefix:  a prefix that is assigned to a specified link

   Off-link:  the opposite of "on-link" (see [RFC4861])

   PIO:  Prefix Information Option [RFC4862]

   RA:  Router Advertisement [RFC4861]

   SLAAC:  Stateless Address Autoconfiguration [RFC4862]

4.  Rationale

   The network administrator might want to indicate to clients that
   requesting a prefix via DHCPv6-PD and using that prefix for address
   assignment (see [RFC9663]) should be preferred over using individual
   addresses from the on-link prefix.  The information is passed to the
   client via a P flag in the PIO.  The reasons for it being a PIO flag
   are as follows:

   *  The information must be contained in the RA because it must be
      available to the client before it decides to form IPv6 addresses
      from the PIO prefix using SLAAC.  Otherwise, the client might use
      SLAAC to form IPv6 addresses from the PIO provided and start using
      them, even if a unique per-client prefix is available via
      DHCPv6-PD.  Forming addresses via SLAAC is suboptimal because if
      the client later acquires a prefix using DHCPv6-PD, it can either
      1) use both the prefix and SLAAC addresses, reducing the
      scalability benefits of using DHCPv6-PD, or 2) remove the SLAAC
      addresses, which would be disruptive for applications that are
      using them.

   *  This information is specific to the particular prefix being
      announced.  For example, a network administrator might want
      clients to assign global addresses from delegated prefixes but
      form Unique Local IPv6 Unicast Addresses [RFC4193] from another
      PIO in the RA using SLAAC.  Also, in a multihoming situation, one
      upstream network might choose to assign prefixes via prefix
      delegation and another via PIOs.

   Note that setting the P flag in a PIO expresses the network
   operator's preference that clients should attempt using DHCPv6-PD
   instead of performing individual address configuration on the prefix.
   For clients that honor this preference by requesting prefix
   delegation, the actual delegated prefix will necessarily be a prefix
   different from the one from the PIO.

5.  P Flag Overview

   The P flag (also called the DHCPv6-PD Preferred Flag) is a 1-bit PIO
   flag, located after the R flag [RFC6275].  The presence of a PIO with
   the P flag set indicates that the network prefers that clients use
   prefix delegation instead of acquiring individual addresses via SLAAC
   or DHCPv6 address assignment.  This implies that the network has a
   DHCPv6 server capable of making DHCPv6 prefix delegations to every
   device on the network, as described in [RFC9663].

   Figure 1 shows the resulting format of the PIO.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |    Length     | Prefix Length |L|A|R|P| Rsvd1 |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                         Valid Lifetime                        |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                       Preferred Lifetime                      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                           Reserved2                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     +                                                               +
     |                                                               |
     +                            Prefix                             +
     |                                                               |
     +                                                               +
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                                  Figure 1

   The P flag is independent of the value of the M and O flags in the
   RA.  If the network desires to delegate prefixes to devices that
   support DHCPv6 prefix delegation but do not support the P flag, it
   SHOULD also set the M or O bits in the RA to 1, because some devices,
   such as Customer Edge (CE) routers [RFC7084], might not initiate
   DHCPv6 prefix delegation if both the M and O bits are set to zero.

6.  Router Behavior

   Routers SHOULD set the P flag to zero by default, unless explicitly
   configured by the administrator, and SHOULD allow the operator to set
   the P flag value for any given prefix advertised in a PIO.  Routers
   MUST allow the P flag to be configured separately from the A flag.
   In particular, enabling or disabling the P flag MUST NOT trigger
   automatic changes in the A flag value set by the router.

7.  Client Behavior

7.1.  Processing the P Flag

   This specification only applies to clients that support DHCPv6 prefix
   delegation.  Clients that do not support DHCPv6 prefix delegation
   MUST ignore the P flag.  The P flag is meaningless for link-local
   prefixes, and any PIO containing the link-local prefix MUST be
   ignored as specified in Section 5.5.3 of [RFC4862].  In the following
   text, all prefixes are assumed not to be link-local.

   For each interface, the client MUST keep a list of every prefix that
   was received from a PIO with the P flag set and currently has a non-
   zero preferred lifetime.  The list affects the behavior of the DHCPv6
   client as follows:

   *  When a prefix's preferred lifetime becomes zero, either because
      the preferred lifetime expires or because the client receives a
      PIO for the prefix with a zero preferred lifetime, the prefix MUST
      be removed from the list.

   *  When the length of the list increases to one, the client SHOULD
      start requesting prefixes via DHCPv6 prefix delegation unless it
      is already doing so.

   *  When the length of the list decreases to zero, the client SHOULD
      stop requesting or renewing prefixes via DHCPv6 prefix delegation
      if it has no other reason to do so.  The lifetimes of any prefixes
      already obtained via DHCPv6 are unaffected.

   *  If the client has already received delegated prefix(es) from one
      or more servers, then any time one or more prefix(es) are added to
      or removed from the list, the client MUST consider this to be a
      change in configuration information as described in
      Section 18.2.12 of [RFC8415].  In that case, the client MUST
      perform a REBIND, unless the list is now empty.  This is in
      addition to performing a REBIND in the other cases required by
      that section.  Issuing a REBIND allows the client to obtain new
      prefixes if necessary, for example, when the network is being
      renumbered.  It also refreshes the state related to the delegated
      prefix(es).

   When a client requests a prefix via DHCPv6-PD, it MUST use the prefix
   length hint (Section 18.2.4 of [RFC8415]) to request a prefix that is
   short enough to form addresses via SLAAC.

   In order to achieve the scalability benefits of using DHCPv6-PD, the
   client SHOULD prefer to form addresses from the delegated prefix
   instead of using individual addresses in the on-link prefix(es).
   Therefore, when the client requests a prefix using DHCPv6-PD, the
   client SHOULD NOT use SLAAC to obtain IPv6 addresses from PIOs with
   the P and A bits set.  Similarly, if all PIOs processed by the client
   have the P bit set, the client SHOULD NOT request individual IPv6
   addresses from DHCPv6, i.e., it SHOULD NOT include any IA_NA options
   in Solicit messages [RFC8415].  The client MAY continue to use
   addresses that are already configured.

   If the client does not obtain any suitable prefixes via DHCPv6-PD
   that are suitable for SLAAC, it MAY choose to disable further
   processing of the P flag on that interface, allowing the client to
   fall back to other address assignment mechanisms, such as forming
   addresses via SLAAC (if the PIO has the A flag set to 1) and/or
   requesting individual addresses via DHCPv6.

7.2.  Using Delegated Prefix(es)

   If the delegated prefix is too long to be used for SLAAC, the client
   MUST ignore it, as Section 7 of [RFC9663] requires the network to
   provide a SLAAC-suitable prefix to clients.  If the prefix is shorter
   than required for SLAAC, the client SHOULD accept it, allocate one or
   more longer prefixes suitable for SLAAC, and use the prefixes as
   described below.

   For every accepted prefix:

   *  The client MAY form as many IPv6 addresses from the prefix as it
      chooses.

   *  The client MAY use the prefix to provide IPv6 addresses to
      internal components such as VMs or containers.

   *  The client MAY use the prefix to allow devices directly connected
      to it to obtain IPv6 addresses.  For example, the client MAY route
      traffic for that prefix to an interface and send an RA containing
      a PIO for the prefix on that interface.  That interface MUST NOT
      be the interface the prefix is obtained from.  If the client
      advertises the prefix on an interface and it has formed addresses
      from the prefix, then it MUST act as though the addresses were
      assigned to that interface for the purposes of Neighbor Discovery
      and Duplicate Address Detection.

   The client MUST NOT send or forward packets with destination
   addresses within a delegated prefix to the interface that it obtained
   the prefix on, as this can cause a routing loop.  This problem will
   not occur if the client has assigned the prefix to another interface.
   Another way the client can prevent this problem is to add to its
   routing table a high-metric discard route for the delegated prefix.

7.3.  Absence of PIOs with the P Bit Set

   The P bit is purely a positive indicator, telling nodes that DHCPv6
   prefix delegation is available and the network prefers that nodes use
   it, even if they do not have any other reason to run a prefix
   delegation client.  The absence of any PIOs with the P bit does not
   carry any kind of signal to the opposite and MUST NOT be processed to
   mean that DHCPv6-PD is absent.  In particular, nodes that run
   DHCPv6-PD due to explicit configuration or by default (e.g., to
   extend the network) MUST NOT disable DHCPv6-PD on the absence of PIOs
   with the P bit set.  A very common example of this are CE routers as
   described by [RFC7084].

7.4.  On-Link Communication

   When the network delegates unique prefixes to clients, each client
   will consider other clients' destination addresses to be off-link,
   because those addresses are from the delegated prefixes and are not
   within any on-link prefix.  When a client sends traffic to another
   client, packets will initially be sent to the default router.  The
   router may respond with an ICMPv6 redirect message (Section 4.5 of
   [RFC4861]).  If the client receives and accepts the redirect, then
   traffic can flow directly from device to device.  Therefore, hosts
   supporting the P flag SHOULD process redirects unless configured
   otherwise.  Hosts that do not process ICMPv6 redirects, and routers
   that do not act on ICMPv6 redirects, may experience higher latency
   while communicating to prefixes delegated to other clients on the
   same link.

7.5.  Source Address Selection

   For the purpose of source address selection [RFC6724], if the host
   creates any addresses from a delegated prefix, it SHOULD treat those
   addresses as if they were assigned to the interface on which the
   prefix was received.  This includes placing them in the candidate set
   and associating them with the outgoing interface when implementing
   Rule 5 of the source address selection algorithm [RFC6724].

8.  Multihoming

   In multi-prefix multihoming, the host generally needs to associate
   the prefix with the router that advertised it (for example, see Rule
   5.5 in [RFC6724]).  If the host supports Rule 5.5, then it SHOULD
   associate each prefix with the link-local address of the DHCPv6
   server or relay from which it received the REPLY packet.  When
   receiving multiple REPLYs carrying the same prefix from distinct
   link-local addresses, the host SHOULD associate that prefix with all
   of these addresses.  This can commonly happen in networks with
   redundant routers and DHCPv6 servers or relays.

9.  Modifications to RFC-Mandated Behavior

9.1.  Changes to RFC 4861

   This document makes the following changes to Section 4.2 of
   [RFC4861]:

   OLD TEXT:

   |  Note: If neither M nor O flags are set, this indicates that no
   |  information is available via DHCPv6.

   NEW TEXT:

   |  Note: If the M, O, or P (RFC 9762) flags are not set, this
   |  indicates that no information is available via DHCPv6.

9.2.  Changes to RFC 4862

   This document makes the following changes to Section 5.5.3 of
   [RFC4862]:

   OLD TEXT:

   |  For each Prefix-Information option in the Router Advertisement:
   |  
   |  a)  If the Autonomous flag is not set, silently ignore the Prefix
   |      Information option.
   |  
   |  b)  If the prefix is the link-local prefix, silently ignore the
   |      Prefix Information option.
   |  
   |  c)  If the preferred lifetime is greater than the valid lifetime,
   |      silently ignore the Prefix Information option.  A node MAY
   |      wish to log a system management error in this case.
   |  
   |  d)  If the prefix advertised is not equal to the prefix of an
   |      address configured by stateless autoconfiguration already in
   |      the list of addresses associated with the interface (where
   |      "equal" means the two prefix lengths are the same and the
   |      first prefix-length bits of the prefixes are identical), and
   |      if the Valid Lifetime is not 0, form an address (and add it to
   |      the list) by combining the advertised prefix with an interface
   |      identifier of the link as follows:

   NEW TEXT:

   |  For each Prefix Information Option in the Router Advertisement:
   |  
   |  a)  If the prefix is the link-local prefix, silently ignore the
   |      Prefix Information Option.
   |  
   |  b)  If the P flag is set and the node implements RFC 9762, it
   |      SHOULD treat the Autonomous flag as if it was unset and use
   |      prefix delegation to obtain addresses as described in RFC
   |      9762.
   |  
   |  c)  If the Autonomous flag is not set, silently ignore the Prefix
   |      Information Option.
   |  
   |  d)  If the preferred lifetime is greater than the valid lifetime,
   |      silently ignore the Prefix Information Option.  A node MAY
   |      wish to log a system management error in this case.
   |  
   |  e)  If the prefix advertised is not equal to the prefix of an
   |      address configured by stateless autoconfiguration already in
   |      the list of addresses associated with the interface (where
   |      "equal" means the two prefix lengths are the same and the
   |      first prefix-length bits of the prefixes are identical) and if
   |      the Valid Lifetime is not 0, form an address (and add it to
   |      the list) by combining the advertised prefix with an interface
   |      identifier of the link as follows:

10.  Security Considerations

   The mechanism described in this document relies on the information
   provided in the RA and therefore shares the same security model as
   SLAAC.  If the network does not implement RA-Guard [RFC6105], an
   attacker might send RAs containing the PIO used by the network, set
   the P flag to 1, and force hosts to ignore the A flag.  In the
   absence of DHCPv6-PD infrastructure, hosts would either obtain no
   IPv6 addresses or, if they fall back to other IPv6 address assignment
   mechanisms such as SLAAC and IA_NA, would experience delays in
   obtaining IPv6 addresses.  If the network does not support
   DHCPv6-Shield [RFC7610], the attacker could also run a rogue DHCPv6
   server, providing the host with invalid prefixes or other invalid
   configuration information.

   The attacker might force hosts to oscillate between DHCPv6-PD and
   PIO-based SLAAC by sending the same set of PIOs with and then without
   the P flag set.  That would cause the clients to issue REBIND
   requests, increasing the load on the DHCP infrastructure.  However,
   Section 14.1 of [RFC8415] requires that DHCPv6-PD clients rate-limit
   transmitted DHCPv6 messages.

   It should be noted that if the network allows rogue RAs to be sent,
   the attacker would be able to disrupt hosts' connectivity anyway, so
   this document doesn't introduce any fundamentally new security
   considerations.

   Security considerations inherent to the PD-per-device model are
   documented in Section 15 of [RFC9663].

11.  Privacy Considerations

   The privacy implications of implementing the P flag and using
   DHCPv6-PD to assign prefixes to hosts are similar to the privacy
   implications of using DHCPv6 to assign individual addresses.  If the
   DHCPv6 infrastructure assigns the same prefix to the same client,
   then an observer might be able to identify clients based on the
   highest 64 bits of the client's address.  Those implications and
   recommended countermeasures are discussed in Section 13 of [RFC9663].

   Implementing the P flag support on a host and receiving will enable
   DHCPv6 on that host if the host receives an RA containing a PIO with
   the P bit set.  Sending DHCPv6 packets may reveal some minor
   additional information about the host, most prominently the hostname.
   This is not a new concern and would apply for any network that uses
   DHCPv6 and sets the M flag in RAs.

   No privacy considerations result from supporting the P flag on the
   sender side.

12.  IANA Considerations

   IANA has made the following allocation in the "IPv6 Neighbor
   Discovery Prefix Information Option Flags" registry [RFC8425]:

       +================+==============================+===========+
       | PIO Option Bit | Description                  | Reference |
       +================+==============================+===========+
       | 3              | P - DHCPv6-PD Preferred Flag | RFC 9762  |
       +----------------+------------------------------+-----------+

                                  Table 1

13.  References

13.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC4861]  Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
              "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
              DOI 10.17487/RFC4861, September 2007,
              <https://www.rfc-editor.org/info/rfc4861>.

   [RFC4862]  Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
              Address Autoconfiguration", RFC 4862,
              DOI 10.17487/RFC4862, September 2007,
              <https://www.rfc-editor.org/info/rfc4862>.

   [RFC6724]  Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
              "Default Address Selection for Internet Protocol Version 6
              (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
              <https://www.rfc-editor.org/info/rfc6724>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8415]  Mrugalski, T., Siodelski, M., Volz, B., Yourtchenko, A.,
              Richardson, M., Jiang, S., Lemon, T., and T. Winters,
              "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
              RFC 8415, DOI 10.17487/RFC8415, November 2018,
              <https://www.rfc-editor.org/info/rfc8415>.

   [RFC8425]  Troan, O., "IANA Considerations for IPv6 Neighbor
              Discovery Prefix Information Option Flags", RFC 8425,
              DOI 10.17487/RFC8425, July 2018,
              <https://www.rfc-editor.org/info/rfc8425>.

13.2.  Informative References

   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005,
              <https://www.rfc-editor.org/info/rfc4193>.

   [RFC6105]  Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J.
              Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105,
              DOI 10.17487/RFC6105, February 2011,
              <https://www.rfc-editor.org/info/rfc6105>.

   [RFC6275]  Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
              Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
              2011, <https://www.rfc-editor.org/info/rfc6275>.

   [RFC7039]  Wu, J., Bi, J., Bagnulo, M., Baker, F., and C. Vogt, Ed.,
              "Source Address Validation Improvement (SAVI) Framework",
              RFC 7039, DOI 10.17487/RFC7039, October 2013,
              <https://www.rfc-editor.org/info/rfc7039>.

   [RFC7084]  Singh, H., Beebee, W., Donley, C., and B. Stark, "Basic
              Requirements for IPv6 Customer Edge Routers", RFC 7084,
              DOI 10.17487/RFC7084, November 2013,
              <https://www.rfc-editor.org/info/rfc7084>.

   [RFC7348]  Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
              L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
              eXtensible Local Area Network (VXLAN): A Framework for
              Overlaying Virtualized Layer 2 Networks over Layer 3
              Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
              <https://www.rfc-editor.org/info/rfc7348>.

   [RFC7610]  Gont, F., Liu, W., and G. Van de Velde, "DHCPv6-Shield:
              Protecting against Rogue DHCPv6 Servers", BCP 199,
              RFC 7610, DOI 10.17487/RFC7610, August 2015,
              <https://www.rfc-editor.org/info/rfc7610>.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

   [RFC9663]  Colitti, L., Linkova, J., Ed., and X. Ma, Ed., "Using
              DHCPv6 Prefix Delegation (DHCPv6-PD) to Allocate Unique
              IPv6 Prefixes per Client in Large Broadcast Networks",
              RFC 9663, DOI 10.17487/RFC9663, October 2024,
              <https://www.rfc-editor.org/info/rfc9663>.

Acknowledgements

   Thanks to Nick Buraglio, Brian Carpenter, Tim Chown, David Farmer,
   Fernando Gont, Susan Hares, Mahesh Jethanandani, Suresh Krishnan, Ted
   Lemon, Andrew McGregor, Tomek Mrugalski, Erik Nordmark, Michael
   Richardson, Patrick Rohr, John Scudder, Ole Trøan, Dirk Von Hugo,
   Éric Vyncke and Timothy Winters for the discussions, reviews, input,
   and contributions.

Authors' Addresses

   Lorenzo Colitti
   Google
   Shibuya 3-21-3,
   Japan
   Email: lorenzo@google.com


   Jen Linkova
   Google
   1 Darling Island Rd
   Pyrmont NSW 2009
   Australia
   Email: furry13@gmail.com, furry@google.com


   Xiao Ma (editor)
   Google
   Shibuya 3-21-3,
   Japan
   Email: xiaom@google.com


   David 'equinox' Lamparter
   NetDEF, Inc.
   04229 Leipzig
   Germany
   Email: equinox@diac24.net, equinox@opensourcerouting.org
