Internet DRAFT - draft-ietf-6man-slaac-renum
draft-ietf-6man-slaac-renum
IPv6 Maintenance (6man) Working Group F. Gont
Internet-Draft SI6 Networks
Updates: 4191, 4861, 4862, 8106 (if approved) J. Zorz
Intended status: Standards Track 6connect
Expires: 3 November 2023 R. Patterson
Sky UK
2 May 2023
Improving the Robustness of Stateless Address Autoconfiguration (SLAAC)
to Flash Renumbering Events
draft-ietf-6man-slaac-renum-07
Abstract
In renumbering scenarios where an IPv6 prefix suddenly becomes
invalid, hosts on the local network will continue using stale
prefixes for an unacceptably long period of time, thus resulting in
connectivity problems. This document improves the reaction of IPv6
Stateless Address Autoconfiguration to such renumbering scenarios.
It formally updates RFC 4191, RFC 4861, RFC 4862, and RFC 8106.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on 3 November 2023.
Copyright Notice
Copyright (c) 2023 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 (https://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
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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
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. SLAAC reaction to Flash-renumbering Events . . . . . . . . . 3
3.1. Renumbering without Explicit Signaling . . . . . . . . . 3
3.2. Renumbering with Explicit Signaling . . . . . . . . . . . 4
4. Improvements to Stateless Address Autoconfiguration
(SLAAC) . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. More Appropriate Neighbor Discovery Option Lifetimes . . 6
4.2. Honor Small PIO Valid Lifetimes . . . . . . . . . . . . . 7
4.3. Interface Initialization . . . . . . . . . . . . . . . . 8
4.4. Conveying Information in Router Advertisement (RA)
Messages . . . . . . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
6. Implementation Status . . . . . . . . . . . . . . . . . . . . 10
6.1. More Appropriate Lifetime Values . . . . . . . . . . . . 10
6.1.1. Router Configuration Variables . . . . . . . . . . . 10
6.2. Honor Small PIO Valid Lifetimes . . . . . . . . . . . . . 11
6.2.1. Linux Kernel . . . . . . . . . . . . . . . . . . . . 11
6.2.2. NetworkManager . . . . . . . . . . . . . . . . . . . 11
6.3. Conveying Information in Router Advertisement (RA)
Messages . . . . . . . . . . . . . . . . . . . . . . . . 11
6.4. Recovery from Stale Configuration Information without
Explicit Signaling . . . . . . . . . . . . . . . . . . . 11
6.4.1. dhcpcd(8) . . . . . . . . . . . . . . . . . . . . . . 11
6.5. Other mitigations implemented in products . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
9.1. Normative References . . . . . . . . . . . . . . . . . . 13
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
In scenarios where network configuration information becomes invalid
without any explicit signaling of that condition, hosts on the local
network will continue using stale information for an unacceptably
long period of time, thus resulting in connectivity problems. This
problem has been discussed in detail in [RFC8978].
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This document updates the Neighbor Discovery specification [RFC4861],
the Stateless Address Autoconfiguration (SLAAC) specification
[RFC4862], and other associated specifications ([RFC4191] and
[RFC8106]), such that hosts can more gracefully deal with the so-
called flash renumbering events, thus improving the robustness of
SLAAC.
2. Terminology
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. SLAAC reaction to Flash-renumbering Events
In some scenarios, the local router triggering the network
renumbering event may try to deprecate the stale information (by
explicitly signaling the network about the renumbering event),
whereas in other scenarios the renumbering event may happen
inadvertently, without the router explicitly signaling the scenario
to local hosts. The following subsections analyze specific
considerations for each of these scenarios.
3.1. Renumbering without Explicit Signaling
In the absence of explicit signalling from SLAAC routers (such as
sending Prefix Information Options (PIOs) with small lifetimes to
deprecate stale prefixes), stale prefixes will remain preferred and
valid according to the Preferred Lifetime and Valid Lifetime
parameters (respectively) of the last received PIO. [RFC4861]
specifies the following default values for PIOs:
* Preferred Lifetime (AdvPreferredLifetime): 604800 seconds (7 days)
* Valid Lifetime (AdvValidLifetime): 2592000 seconds (30 days)
This means that, in the absence of explicit signaling by a SLAAC
router to deprecate a prefix, it will take a host 7 days (one week)
to deprecate the corresponding addresses, and 30 days (one month) to
eventually remove any addresses configured for the stale prefix.
Clearly, employing such long default values is unacceptable for most
deployment scenarios that may experience flash-renumbering events.
NOTE:
[RFC8978] provides an operational recommendation for Customer Edge
(CE) routers to override the standard default Preferred Lifetime
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(AdvPreferredLifetime) and Valid Lifetime (AdvValidLifetime) to
2700 seconds (45 minutes) and 5400 seconds (90 minutes),
respectively, thus improving the state of affairs for CE router
scenarios.
Similarly, other Neighbor Discovery options employ unnecessarily long
default lifetimes that are unacceptable for most deployment scenarios
that may experience flash-renumbering events.
Use of more appropriate timers in Router Advertisement messages can
help limit the amount of time that hosts will maintain stale
configuration information. Thus, Section 4.1 formally specifies the
use of more appropriate (i.e., shorter) default lifetimes for
Neighbor Discovery options.
3.2. Renumbering with Explicit Signaling
In scenarios where a local router is aware about the renumbering
event, it may try to phase out the stale network configuration
information. In these scenarios, there are two aspects to be
considered:
* The amount of time during which the router should continue trying
to deprecate the stale network configuration information.
* The ability of SLAAC hosts to phase out stale configuration.
Since the network could be become partitioned at any arbitrary time
and for an arbitrarily long period of time, routers need to
contemplate the possible scenario where hosts receive an RA message,
and the network subsequently becomes partitioned. This means that in
order to reliably deprecate stale information, a router would should
try to deprecate such information for a period of time equal to the
associated Neighbor Discovery option lifetime used when the
information was advertised.
NOTE:
For example, it should try to deprecate a prefix (via a PIO) for a
period of time equal to the "Preferred Lifetime" used when
advertising the prefix, and try to invalidate the prefix for a
period of time equal to the "Valid Lifetime" (see Section 12 of
[RFC4861]) used when advertising the prefix.
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Once the number of seconds in the original "Preferred Lifetime"
have elapsed, all hosts will have deprecated the corresponding
addresses, while once the number of seconds in the "Valid
Lifetime" have elapsed, the corresponding addresses will be
invalidated and removed.
Thus, use of more appropriate default lifetimes for Neighor Discovery
options, as specified in Section 4.1, would reduce the amount of time
stale options would need to be advertised by a router to ensure that
the associated information is phased out.
In the case of Prefix Information Options (PIOs), in scenarios where
a router has positive knowledge that a prefix has become invalid (and
thus could signal this condition to local hosts), the current
specifications will prevent SLAAC hosts from fully recovering from
such stale information: Item "e)" of Section 5.5.3 of [RFC4862]
specifies that an RA may never reduce the "RemainingLifetime" to less
than two hours. Additionally, if the RemainingLifetime of an address
is smaller than 2 hours, then a Valid Lifetime smaller than 2 hours
will be ignored. The inability to invalidate a stale prefix may
prevent communications with the new "owners" of a prefix, and thus is
highly undesirable. However, the Preferred Lifetime of an address
*may* be reduced to any value to avoid the use of a stale prefix for
new communications.
Section 4.2 formally updates [RFC4862] to remove this restriction,
such that hosts may react to the advertised "Valid Lifetime" even if
it is smaller than 2 hours. Section 4.3 recommends that routers
disseminate network configuration information when a network
interface is initialized, such that new configuration information
propagates in a timelier manner.
4. Improvements to Stateless Address Autoconfiguration (SLAAC)
The following subsections update [RFC4861] and [RFC4862], such that
the problem discussed in this document is mitigated. The updates in
the following subsections are mostly orthogonal, and mitigate
different aspects of SLAAC that prevent a timely reaction to flash
renumbering events:
* Reduce the default Valid Lifetime and Preferred Lifetime of PIOs
(Section 4.1):
This helps limit the amount of time a host may employ stale
information, and also limits the amount of time a router needs to
try to deprecate stale information.
* Honor PIOs with small Valid Lifetimes (Section 4.2):
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This allows routers to invalidate stale prefixes, since otherwise
[RFC4861] would prevent hosts from honoring PIOs with a Valid
Lifetime smaller than two hours.
* Recommend routers to retransmit configuration information upon
interface initialization/reinitialization (Section 4.3):
This helps spread the new information in a timelier manner.
* Recommend routers to always send all options (i.e. the complete
configuration information) in RA messages, and in the smallest
possible number of packets (Section 4.4):
This helps propagate the same information to all hosts.
4.1. More Appropriate Neighbor Discovery Option Lifetimes
This document defines the following variables to be employed for the
default lifetimes of Neighbor Discovery options:
* ND_DEFAULT_PREFERRED_LIFETIME: max(AdvDefaultLifetime, 3 *
MaxRtrAdvInterval)
* ND_DEFAULT_VALID_LIFETIME: 2 * ND_DEFAULT_PREFERRED_LIFETIME
where:
AdvDefaultLifetime:
Router configuration variable specified in [RFC4861], which
specifies the value to be placed in the Router Lifetime field of
Router Advertisements sent from the interface, in seconds.
MaxRtrAdvInterval:
Router configuration variable specified in [RFC4861], which
specifies the maximum time allowed between sending unsolicited
multicast Router Advertisements from the interface, in seconds.
max():
A function that computes the maximum of its arguments.
NOTE:
The expression above computes of maximum among AdvDefaultLifetime
and "3 * MaxRtrAdvInterval" (the default value of
AdvDefaultLifetime, as per [RFC4861]) to accommodate the case
where an operator might simply want to disable one local router
for maintenance, while still having the router advertise SLAAC
configuration information.
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[RFC4861] specifies the default value of MaxRtrAdvInterval as 600
seconds, and the default value of AdvDefaultLifetime as 3 *
MaxRtrAdvInterval. Therefore, when employing default values for
MaxRtrAdvInterval and AdvDefaultLifetime, the default values of
ND_DEFAULT_PREFERRED_LIFETIME and ND_DEFAULT_VALID_LIFETIME become
1800 seconds (30 minutes) and 3600 seconds (1 one hour),
respectively. We note that when implementing BCP202 [RFC7772],
AdvDefaultLifetime will typically be in the range of 45-90
minutes, and therefore the value of ND_DEFAULT_PREFERRED_LIFETIME
will be in the range 45-90 minutes, while the value of
ND_DEFAULT_VALID_LIFETIME will be in the range of 90-180 minutes.
This document formally updates [RFC4861] to modify the default values
of the Preferred Lifetime and the Valid Lifetime of PIOs as follows:
* AdvPreferredLifetime: ND_DEFAULT_PREFERRED_LIFETIME
* AdvValidLifetime: ND_DEFAULT_VALID_LIFETIME
This document formally updates [RFC4191] to specify the default Route
Lifetime of Route Information Options (RIOs) as follows:
* Route Lifetime: Default: ND_DEFAULT_PREFERRED_LIFETIME
This document formally updates [RFC8106] to modify the default
Lifetime of Recursive DNS Server Options as:
* Lifetime: Default: ND_DEFAULT_PREFERRED_LIFETIME
Additionally, this document formally updates [RFC8106] to modify the
default Lifetime of DNS Search List Options as:
* Lifetime: Default: ND_DEFAULT_PREFERRED_LIFETIME
4.2. Honor Small PIO Valid Lifetimes
The entire item "e)" (pp. 19-20) from Section 5.5.3 of [RFC4862] is
replaced with the following text:
e) If the advertised prefix is equal to the prefix of an address
configured by stateless autoconfiguration in the list, the valid
lifetime and the preferred lifetime of the address should be
updated by processing the Valid Lifetime and the Preferred
Lifetime (respectively) in the received advertisement.
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RATIONALE:
* This change allows hosts to react to the signal provided by a
router that has positive knowledge that a prefix has become
invalid.
* The behavior described in [RFC4862] had been incorporated
during the revision of the original IPv6 Stateless Address
Autoconfiguration specification ([RFC1971]). At the time, the
IPNG working group decided to mitigate the attack vector
represented by Prefix Information Options with very short
lifetimes, on the premise that these packets represented a
bigger risk than other ND-based attack vectors [IPNG-minutes].
While reconsidering the trade-offs represented by such
decision, we conclude that the drawbacks of the aforementioned
mitigation outweigh the possible benefits.
In scenarios where RA-based attacks are of concern, proper
mitigations such as RA-Guard [RFC6105] [RFC7113] or SEND
[RFC3971] should be implemented.
4.3. Interface Initialization
When an interface is initialized, it is paramount that network
configuration information is propagated on the corresponding network
(particularly in scenarios where an interface has been re-
initialized, and the conveyed information has changed). Thus, this
document replaces the following text from Section 6.2.4 of [RFC4861]:
In such cases, the router MAY transmit up to
MAX_INITIAL_RTR_ADVERTISEMENTS unsolicited advertisements, using
the same rules as when an interface becomes an advertising
interface.
with:
In such cases, the router SHOULD transmit
MAX_INITIAL_RTR_ADVERTISEMENTS unsolicited advertisements, using
the same rules as when an interface becomes an advertising
interface.
RATIONALE:
* Use of stale information can lead to interoperability problems.
Therefore, it is important that new configuration information
propagates in a timelier manner to all hosts.
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NOTE:
[RFC9096] specifies recommendations for CPE routers to signal any
stale network configuration information.
4.4. Conveying Information in Router Advertisement (RA) Messages
Intentionally omitting information in Router Advertisements may
prevent the propagation of such information, and may represent a
challenge for hosts that need to infer whether they have received a
complete set of SLAAC configuration information. As a result, this
section recommends that, to the extent that is possible, RA messages
contain a complete set of SLAAC information.
This document replaces the following text from Section 6.2.3 of
[RFC4861]:
A router MAY choose not to include some or all options when
sending unsolicited Router Advertisements. For example, if prefix
lifetimes are much longer than AdvDefaultLifetime, including them
every few advertisements may be sufficient. However, when
responding to a Router Solicitation or while sending the first few
initial unsolicited advertisements, a router SHOULD include all
options so that all information (e.g., prefixes) is propagated
quickly during system initialization.
If including all options causes the size of an advertisement to
exceed the link MTU, multiple advertisements can be sent, each
containing a subset of the options.
with:
When sending Router Advertisements, a router SHOULD include all
options.
If including all options would cause the size of an advertisement
to exceed the link MTU, multiple advertisements can be sent, each
containing a subset of the options. In all cases, routers SHOULD
convey all information using the smallest possible number of
packets, and SHOULD convey options of the same type in the same
packet to the extent possible.
RATIONALE:
* Sending information in the smallest possible number of packets
was somewhat already implied by the original text in [RFC4861].
Including all options when sending RAs leads to simpler code
(as opposed to dealing with special cases where specific
information is intentionally omitted), and also helps hosts
infer when they have received a complete set of SLAAC
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configuration information. Note that while [RFC4861] allowed
some RAs to omit some options, to the best of the authors'
knowledge, all SLAAC router implementations always send all
options in the smallest possible number of packets. Therefore,
this section simply aligns the protocol specifications with
existing implementation practice.
5. IANA Considerations
This document has no actions for IANA.
6. Implementation Status
[NOTE: This section is to be removed by the RFC-Editor before this
document is published as an RFC.]
This section summarizes the implementation status of the updates
proposed in this document. In some cases, they correspond to
variants of the mitigations proposed in this document (e.g., use of
reduced default lifetimes for PIOs, albeit using different values
than those recommended in this document). In such cases, we believe
these implementations signal the intent to deal with the problems
described in [RFC8978] while lacking any guidance on the best
possible approach to do it.
6.1. More Appropriate Lifetime Values
6.1.1. Router Configuration Variables
6.1.1.1. rad(8)
We have produced a patch for OpenBSD's rad(8) [rad] that employs the
default lifetimes recommended in this document, albeit it has not yet
been committed to the tree. The patch is available at:
<https://www.gont.com.ar/code/fgont-patch-rad-pio-lifetimes.txt>.
6.1.1.2. radvd(8)
The radvd(8) daemon [radvd], normally employed by Linux-based router
implementations, currently employs different default lifetimes than
those recommended in [RFC4861]. radvd(8) employs the following
default values [radvd.conf]:
* Preferred Lifetime: 14400 seconds (4 hours)
* Valid Lifetime: 86400 seconds (1 day)
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This is not following the specific recommendation in this document,
but is already a deviation from the current standards.
6.2. Honor Small PIO Valid Lifetimes
6.2.1. Linux Kernel
A Linux kernel implementation of this document has been committed to
the net-next tree. The implementation was produced in April 2020 by
Fernando Gont <fgont@si6networks.com>. The corresponding patch can
be found at: <https://patchwork.ozlabs.org/project/netdev/
patch/20200419122457.GA971@archlinux-current.localdomain/>
6.2.2. NetworkManager
NetworkManager [NetworkManager] processes RA messages with a Valid
Lifetime smaller than two hours as recommended in this document.
6.3. Conveying Information in Router Advertisement (RA) Messages
We know of no implementation that splits network configuration
information into multiple RA messages.
6.4. Recovery from Stale Configuration Information without Explicit
Signaling
6.4.1. dhcpcd(8)
The dhcpcd(8) daemon [dhcpcd], a user-space SLAAC implementation
employed by some Linux-based and BSD-derived operating systems, will
set the Preferred Lifetime of addresses corresponding to a given
prefix to 0 when a single RA from the router that previously
advertised the prefix fails to advertise the corresponding prefix.
However, it does not affect the corresponding Valid Lifetime.
Therefore, it can be considered a partial implementation of this
feature.
6.5. Other mitigations implemented in products
[FRITZ] is a Customer Edge Router that tries to deprecate stale
prefixes by advertising stale prefixes with a Preferred Lifetime of
0, and a Valid Lifetime of 2 hours (or less). There are two things
to note with respect to this implementation:
* Rather than recording prefixes on stable storage (as recommended
in [RFC9096]), this implementation checks the source address of
IPv6 packets, and assumes that usage of any address that does not
correspond to a prefix currently-advertised by the Customer Edge
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Router is the result of stale network configuration information.
Hence, upon receipt of a packet that employs a source address that
does not correspond to a currently-advertised prefix, this
implementation will start advertising the corresponding prefix
with small lifetimes, with the intent of deprecating it.
* Possibly as a result of item "e)" (pp. 19-20) from Section 5.5.3
of [RFC4862] (discussed in Section 4.2 of this document), upon
first occurrence of a stale prefix, this implementation will
employ a decreasing Valid Lifetime, starting from 2 hours (7200
seconds), as opposed to a Valid Lifetime of 0.
7. Security Considerations
The protocol update in Section 4.2 could allow an on-link attacker to
perform a Denial of Service attack against local hosts, by sending a
forged RA with a PIO with a Valid Lifetime of 0. Upon receipt of
that packet, local hosts would invalidate the corresponding prefix,
and therefore remove any addresses configured for that prefix,
possibly terminating e.g. associated TCP connections. However, an
attacker may achieve similar effects via a number other Neighbor
Discovery (ND) attack vectors, such as directing traffic to a non-
existing node until ongoing TCP connections time out, or performing a
ND-based man-in-the-middle (MITM) attack and subsequently forging TCP
RST segments to cause on-going TCP connections to be reset. Thus,
for all practical purposes, this attack vector does not really
represent any greater risk than other ND attack vectors. As noted in
Section 4.2 , in scenarios where RA-based attacks are of concern,
proper mitigations such as RA-Guard [RFC6105] [RFC7113] or SEND
[RFC3971] should be implemented.
8. Acknowledgments
The authors would like to thank (in alphabetical order) Mikael
Abrahamsson, Tore Anderson, Luis Balbinot, Brian Carpenter, Lorenzo
Colitti, Owen DeLong, Gert Doering, Thomas Haller, Nick Hilliard, Bob
Hinden, Philip Homburg, Lee Howard, Christian Huitema, Tatuya Jinmei,
Erik Kline, Ted Lemon, Jen Linkova, Albert Manfredi, Roy Marples,
Florian Obser, Jordi Palet Martinez, Michael Richardson, Hiroki Sato,
Mark Smith, Hannes Frederic Sowa, Dave Thaler, Tarko Tikan, Ole
Troan, Eduard Vasilenko, and Loganaden Velvindron, for providing
valuable comments on earlier versions of this document.
Fernando would like to thank Alejandro D'Egidio and Sander Steffann
for a discussion of these issues, which led to the publication of
[RFC8978], and eventually to this document.
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Fernando would also like to thank Brian Carpenter who, over the
years, has answered many questions and provided valuable comments
that has benefited his protocol-related work.
9. References
9.1. 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>.
[RFC7772] Yourtchenko, A. and L. Colitti, "Reducing Energy
Consumption of Router Advertisements", BCP 202, RFC 7772,
DOI 10.17487/RFC7772, February 2016,
<https://www.rfc-editor.org/info/rfc7772>.
[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>.
9.2. Informative References
[dhcpcd] Marples, R., "dhcpcd - a DHCP client",
<https://roy.marples.name/projects/dhcpcd/>.
[FRITZ] Gont, F., "Quiz: Weird IPv6 Traffic on the Local Network
(updated with solution)", SI6 Networks Blog, February
2016, <https://www.si6networks.com/2016/02/16/quiz-weird-
ipv6-traffic-on-the-local-network-updated-with-solution/>.
[IPNG-minutes]
IETF, "IPNG working group (ipngwg) Meeting Minutes",
Proceedings of the thirty-eightt Internet Engineering Task
Force , April 1997, <https://www.ietf.org/
proceedings/38/97apr-final/xrtftr47.htm>.
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[NetworkManager]
NetworkManager, "NetworkManager web site",
<https://wiki.gnome.org/Projects/NetworkManager>.
[rad] Obser, F., "OpenBSD Router Advertisement Daemon - rad(8)",
<https://cvsweb.openbsd.org/src/usr.sbin/rad/>.
[radvd] Hawkins, R. and R. Johnson, "Linux IPv6 Router
Advertisement Daemon (radvd)",
<http://www.litech.org/radvd/>.
[radvd.conf]
Hawkins, R. and R. Johnson, "radvd.conf - configuration
file of the router advertisement daemon",
<https://github.com/reubenhwk/radvd/blob/master/
radvd.conf.5.man>.
[RFC1971] Thomson, S. and T. Narten, "IPv6 Stateless Address
Autoconfiguration", RFC 1971, DOI 10.17487/RFC1971, August
1996, <https://www.rfc-editor.org/info/rfc1971>.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971,
DOI 10.17487/RFC3971, March 2005,
<https://www.rfc-editor.org/info/rfc3971>.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, DOI 10.17487/RFC4191,
November 2005, <https://www.rfc-editor.org/info/rfc4191>.
[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>.
[RFC7113] Gont, F., "Implementation Advice for IPv6 Router
Advertisement Guard (RA-Guard)", RFC 7113,
DOI 10.17487/RFC7113, February 2014,
<https://www.rfc-editor.org/info/rfc7113>.
[RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Options for DNS Configuration",
RFC 8106, DOI 10.17487/RFC8106, March 2017,
<https://www.rfc-editor.org/info/rfc8106>.
Gont, et al. Expires 3 November 2023 [Page 14]
Internet-Draft Reaction to Renumbering Events May 2023
[RFC8978] Gont, F., Žorž, J., and R. Patterson, "Reaction of IPv6
Stateless Address Autoconfiguration (SLAAC) to Flash-
Renumbering Events", RFC 8978, DOI 10.17487/RFC8978, March
2021, <https://www.rfc-editor.org/info/rfc8978>.
[RFC9096] Gont, F., Žorž, J., Patterson, R., and B. Volz, "Improving
the Reaction of Customer Edge Routers to IPv6 Renumbering
Events", BCP 234, RFC 9096, DOI 10.17487/RFC9096, August
2021, <https://www.rfc-editor.org/info/rfc9096>.
Authors' Addresses
Fernando Gont
SI6 Networks
Segurola y Habana 4310, 7mo Piso
Villa Devoto
Ciudad Autonoma de Buenos Aires
Argentina
Email: fgont@si6networks.com
URI: https://www.si6networks.com
Jan Zorz
6connect
Email: jan@connect.com
Richard Patterson
Sky UK
Email: richard.patterson@sky.uk
Gont, et al. Expires 3 November 2023 [Page 15]
