IPv6 Operations Working Group (v6ops) F. Gont
Internet-Draft SI6 Networks
Intended status: Informational N. Hilliard
Expires: January 26, 2021 INEX
G. Doering
SpaceNet AG
W. Kumari
Google
G. Huston
APNIC
July 25, 2020
Operational Implications of IPv6 Packets with Extension Headers
draft-gont-v6ops-ipv6-ehs-packet-drops-04
Abstract
This document summarizes the security and operational implications of
IPv6 extension headers, and attempts to analyze reasons why packets
with IPv6 extension headers may be dropped in the public Internet.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 26, 2021.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Previous Work on IPv6 Extension Headers . . . . . . . . . . . 3
4. Security Implications . . . . . . . . . . . . . . . . . . . . 4
5. Operational Implications . . . . . . . . . . . . . . . . . . 6
5.1. Requirement to process required layer-3/layer-4
information . . . . . . . . . . . . . . . . . . . . . . . 6
5.2. Route-Processor Protection . . . . . . . . . . . . . . . 8
5.3. Inability to Perform Fine-grained Filtering . . . . . . . 9
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Normative References . . . . . . . . . . . . . . . . . . 10
9.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
IPv6 Extension Headers (EHs) allow for the extension of the IPv6
protocol, and provide support for core functionality such as IPv6
fragmentation. However, common implementation limitations suggest
that EHs present a challenge for IPv6 packet routing equipment, and
evidence exists that IPv6 packets with EHs may be intentionally
dropped in the public Internet in some network deployments.
The authors of this document have been involved in numerous
discussions about IPv6 extension headers (both within the IETF and in
other fora), and have noticed that the security and operational
implications associated with IPv6 EHs were unknown to the larger
audience participating in these discussions.
This document has the following goals:
o Raise awareness about the security and operational implications of
IPv6 Extension Headers, and presents reasons why some networks
intentionally drop packets containing IPv6 Extension Headers.
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o Highlight areas where current IPv6 support by networking devices
maybe sub-optimal, such that the aforementioned support is
improved.
o Highlight operational issues associated with IPv6 extension
headers, such that those issues are considered in IETF
standardization efforts.
Section 3 of this document summarizes the previous work that has been
carried out in the area of IPv6 extension headers. Section 4 briefly
discusses the security implications of IPv6 Extension Headers, while
Section 5 discusses their operational implications.
2. Disclaimer
This document analyzes the operational challenges represented by
packets that employ IPv6 Extension Headers, and documents some of the
operational reasons for which these packets may be dropped in the
public Internet. This document IS NOT a recommendation to drop such
packets, but rather an analysis of why they're dropped.
3. Previous Work on IPv6 Extension Headers
Some of the implications of IPv6 Extension Headers have been
discussed in IETF circles. For example, [I-D.taylor-v6ops-fragdrop]
discusses a rationale for which operators drop IPv6 fragments.
[I-D.wkumari-long-headers] discusses possible issues arising from
"long" IPv6 header chains. [RFC7045] clarifies how intermediate
nodes should deal with IPv6 extension headers.
[I-D.kampanakis-6man-ipv6-eh-parsing] describes how inconsistencies
in the way IPv6 packets with extension headers are parsed by
different implementations may result in evasion of security controls,
and presents guidelines for parsing IPv6 extension headers with the
goal of providing a common and consistent parsing methodology for
IPv6 implementations. [I-D.ietf-opsec-ipv6-eh-filtering] analyzes
the security implications of IPv6 EHs, and the operational
implications of dropping packets that employ IPv6 EHs and associated
options. [RFC6980] analyzes the security implications of employing
IPv6 fragmentation with Neighbor Discovery for IPv6, and formally
recommends against such usage. Finally, [RFC7113] discusses how some
popular RA-Guard implementations are subject to evasion by means of
IPv6 extension headers. [I-D.ietf-intarea-frag-fragile] analyzes the
fragility introduced by IP fragmentation.
A number of recent RFCs have discussed issues related to IPv6
extension headers, specifying updates to a previous revision of the
IPv6 standard ([RFC2460]), which have now been incorporated into the
current IPv6 core standard ([RFC8200]). Namely,
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o [RFC5095] discusses the security implications of Routing Header
Type 0 (RTH0), and deprecates it.
o [RFC5722] analyzes the security implications of overlapping
fragments, and provides recommendations in this area.
o [RFC7112] discusses the issues arising in a specific fragmentation
case where the IPv6 header chain is fragmented into two or more
fragments (and formally forbids such fragmentation case).
o [RFC6946] discusses a flawed (but common) processing of the so-
called IPv6 "atomic fragments", and specified improved processing
of such packets.
o [RFC8021] deprecates the generation of IPv6 atomic fragments.
o [RFC8504] allows hosts to enforce limits on the number of options
included in IPv6 EHs.
o [RFC7739] discusses the security implications of predictable
fragment Identification values, and provides recommendations for
the generation of these values.
Additionally, [RFC8200] has relaxed the requirement that "all nodes
examine and process the Hop-by-Hop Options header" from [RFC2460], by
specifying that only to nodes that have been explicitly configured to
process the Hop-by-Hop Options header are required to do so.
A number of studies have measured the extent to which packets
employing IPv6 extension headers are filtered in the public Internet.
Some preliminary measurements regarding the extent to which packet
containing IPv6 EHs are dropped in the public Internet were presented
in [PMTUD-Blackholes], [Gont-IEPG88], [Gont-Chown-IEPG89], and
[Linkova-Gont-IEPG90]. [RFC7872] presents more comprehensive results
and documents the methodology for obtaining the presented results.
[Huston-2017] measures packet drops resulting from IPv6 fragmentation
when communicating with DNS servers.
4. Security Implications
The security implications of IPv6 Extension Headers generally fall
into one or more of these categories:
o Evasion of security controls
o DoS due to processing requirements
o DoS due to implementation errors
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o Extension Header-specific issues
Unlike IPv4 packets where the upper-layer protocol can be trivially
found by means of the "IHL" ("Internet Header Length") IPv4 header
field, the structure of IPv6 packets is more flexible and complex,
and may represent a challenge for devices that need to find this
information, since locating upper-layer protocol information requires
that all IPv6 extension headers be examined. This has presented
implementation difficulties, and packet filtering mechanisms that
require upper-layer information (even if just the upper layer
protocol type) have been found to be trivially evasible by inserting
IPv6 Extension Headers between the main IPv6 header and the upper
layer protocol. [RFC7113] describes this issue for the RA-Guard
case, but the same techniques can be employed to circumvent other
IPv6 firewall and packet filtering mechanisms. Additionally,
implementation inconsistencies in packet forwarding engines may
result in evasion of security controls
[I-D.kampanakis-6man-ipv6-eh-parsing] [Atlasis2014] [BH-EU-2014].
Packets that use IPv6 Extension Headers may have a negative
performance impact on the handling devices. Unless appropriate
mitigations are put in place (e.g., packet dropping and/or rate-
limiting), an attacker could simply send a large amount of IPv6
traffic employing IPv6 Extension Headers with the purpose of
performing a Denial of Service (DoS) attack (see Section 5 for
further details).
NOTE:
In the most trivial case, a packet that includes a Hop-by-Hop
Options header might go through the slow forwarding path, and be
processed by the router's CPU. Another possible case might be
that in which a router that has been configured to enforce an ACL
based on upper-layer information (e.g., upper layer protocol or
TCP Destination Port), needs to process the entire IPv6 header
chain (in order to find the required information), causing the
packet to be processed in the slow path [Cisco-EH-Cons]. We note
that, for obvious reasons, the aforementioned performance issues
may affect other devices such as firewalls, Network Intrusion
Detection Systems (NIDS), etc. [Zack-FW-Benchmark]. The extent
to which these devices are affected is typically implementation-
dependent.
IPv6 implementations, like all other software, tend to mature with
time and wide-scale deployment. While the IPv6 protocol itself has
existed for over 20 years, serious bugs related to IPv6 Extension
Header processing continue to be discovered. Because there is
currently little operational reliance on IPv6 Extension headers, the
corresponding code paths are rarely exercised, and there is the
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potential for bugs that still remain to be discovered in some
implementations.
IPv6 Fragment Headers are employed to allow fragmentation of IPv6
packets. While many of the security implications of the
fragmentation / reassembly mechanism are known from the IPv4 world,
several related issues have crept into IPv6 implementations. These
range from denial of service attacks to information leakage, as
discussed in [RFC7739], [Bonica-NANOG58] and [Atlasis2012]).
5. Operational Implications
5.1. Requirement to process required layer-3/layer-4 information
Intermediate systems and middleboxes that need to find the layer-4
header must process the entire IPv6 extension header chain. When
such devices are unable to obtain the required information, they may
simply drop the corresponding packets. The following subsections
discuss some of reasons for which such layer-4 information may be
needed by an intermediate systems or middlebox, and why packets
containing IPv6 extension headers may represent a challenge in such
scenarios.
5.1.1. Packet Forwarding Engine Constraints
Most modern routers use dedicated hardware (e.g. ASICs or NPUs) to
determine how to forward packets across their internal fabrics (see
[IEPG94-Scudder] and [APNIC-Scudder] for details). One of the common
methods of handling next-hop lookup is to send a small portion of the
ingress packet to a lookup engine with specialised hardware (e.g.
ternary CAM or RLDRAM) to determine the packet's next-hop. Technical
constraints mean that there is a trade-off between the amount of data
sent to the lookup engine and the overall performance of the lookup
engine. If more data is sent, the lookup engine can inspect further
into the packet, but the overall performance of the system will be
reduced. If less data is sent, the overall performance of the router
will be increased but the packet lookup engine may not be able to
inspect far enough into a packet to determine how it should be
handled.
NOTE:
For example, current high-end routers can use up to 192 bytes of
header (Cisco ASR9000 Typhoon) or 384 bytes of header (Juniper MX
Trio)
If a hardware forwarding engine on a modern router cannot make a
forwarding decision about a packet because critical information is
not sent to the look-up engine, then the router will normally drop
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the packet. Historically, some packet forwarding engines punted
packets of this form to the control plane for more in-depth analysis,
but this is unfeasible on most current router architectures as a
result of the vast difference between the hardware forwarding
capacity of the router and processing capacity of the control plane
and the size of the management link which connects the control plane
to the forwarding plane.
If an IPv6 header chain is sufficiently long that its header exceeds
the packet look-up capacity of the router, then it may be dropped due
to hardware inability to determine how it should be handled.
5.1.2. ECMP and Hash-based Load-Sharing
In the case of ECMP (equal cost multi path) load sharing, the router
on the sending side of the link needs to make a decision regarding
which of the links to use for a given packet. Since round-robin
usage of the links is usually avoided in order to prevent packet
reordering, forwarding engines need to use a mechanism which will
consistently forward the same data streams down the same forwarding
paths. Most forwarding engines achieve this by calculating a simple
hash using an n-tuple gleaned from a combination of layer-2 through
to layer-4 packet header information. This n-tuple will typically
use the src/dst MAC address, src/dst IP address, and if possible
further layer-4 src/dst port information. As layer-4 port
information increases the entropy of the hash, it is normally highly
desirable to use it where possible.
We note that in the IPv6 world, flows are expected to be identified
by means of the IPv6 Flow Label [RFC6437]. Thus, ECMP and Hash-based
Load-Sharing would be possible without the need to process the entire
IPv6 header chain to obtain upper-layer information to identify
flows. However, we note that for a long time many IPv6
implementations failed to set the Flow Label, and ECMP and Hash-based
Load-Sharing devices also did not employ the Flow Label for
performing their task.
Clearly, widespread support of [RFC6437] would relieve middle-boxes
from having to process the entire IPv6 header chain, making Flow
Label-based ECMP and Hash-based Load-Sharing [RFC6438] feasible.
While support of [RFC6437] is currently widespread for all popular
host implementations, there is no existing data regarding the extent
to which the Flow Label has superseded the use of transport protocol
port numbers for ECMP.
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5.1.3. Enforcing infrastructure ACLs
Generally speaking, infrastructure ACLs (iACLs) drop unwanted packets
destined to parts of a provider's infrastructure, because they are
not operationally needed and can be used for attacks of different
sorts against the router's control plane. Some traffic needs to be
differentiated depending on layer-3 or layer-4 criteria to achieve a
useful balance of protection and functionality, for example:
o Permit some amount of ICMP echo (ping) traffic towards the
router's addresses for troubleshooting.
o Permit BGP sessions on the shared network of an exchange point
(potentially differentiating between the amount of packets/seconds
permitted for established sessions and connection establishment),
but do not permit other traffic from the same peer IP addresses.
5.1.4. DDoS Management and Customer Requests for Filtering
The case of customer DDoS protection and edge-to-core customer
protection filters is similar in nature to the infrastructure ACL
protection. Similar to infrastructure ACL protection, layer-4 ACLs
generally need to be applied as close to the edge of the network as
possible, even though the intent is usually to protect the customer
edge rather than the provider core. Application of layer-4 DDoS
protection to a network edge is often automated using Flowspec
[RFC5575].
For example, a web site which normally only handled traffic on TCP
ports 80 and 443 could be subject to a volumetric DDoS attack using
NTP and DNS packets with randomised source IP address, thereby
rendering traditional [RFC5635] source-based real-time black hole
mechanisms useless. In this situation, DDoS protection ACLs could be
configured to block all UDP traffic at the network edge without
impairing the web server functionality in any way. Thus, being able
to block arbitrary protocols at the network edge can avoid DDoS-
related problems both in the provider network and on the customer
edge link.
5.2. Route-Processor Protection
Most modern routers have a fast hardware-assisted forwarding plane
and a loosely coupled control plane, connected together with a link
that has much less capacity than the forwarding plane could handle.
Traffic differentiation cannot be done by the control plane side,
because this would overload the internal link connecting the
forwarding plane to the control plane.
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The Hop-by-Hop Options header has been particularly challenging
since, in most (if not all) implementations, it has typically caused
the corresponding packet to be punted to a software path. As a
result, operators usually drop IPv6 packets containing this extension
header. Please see [RFC6192] for advice regarding protection of the
router control plane.
5.3. Inability to Perform Fine-grained Filtering
Some router implementations lack fine-grained filtering of IPv6
extension headers. For example, an operator may want to drop packets
containing Routing Header Type 0 (RHT0) but may only be able to
filter on the extension header type (Routing Header). As a result,
the operator may end up enforcing a more coarse filtering policy
(e.g. "drop all packets containing a Routing Header" vs. "only drop
packets that contain a Routing Header Type 0").
6. IANA Considerations
There are no IANA registries within this document. The RFC-Editor
can remove this section before publication of this document as an
RFC.
7. Security Considerations
The security implications of IPv6 extension headers are discussed in
Section 4. This document does not introduce any new security issues.
8. Acknowledgements
The authors would like to thank (in alphabetical order) Mikael
Abrahamsson, Fred Baker, Brian Carpenter, Tom Herbert, Lee Howard,
Sander Steffann, Eric Vyncke, and Andrew Yourtchenko, for providing
valuable comments on earlier versions of this document.
Additionally, the authors would like to thank participants of the
v6ops working group for their valuable input on the topics that led
to the publication of this document.
Fernando Gont would like to thank Jan Zorz / Go6 Lab
<http://go6lab.si/>, Jared Mauch, and Sander Steffann
<http://steffann.nl/>, for providing access to systems and networks
that were employed to perform experiments and measurements involving
packets with IPv6 Extension Headers.
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9. References
9.1. Normative References
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <https://www.rfc-editor.org/info/rfc2460>.
[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095,
DOI 10.17487/RFC5095, December 2007,
<https://www.rfc-editor.org/info/rfc5095>.
[RFC5722] Krishnan, S., "Handling of Overlapping IPv6 Fragments",
RFC 5722, DOI 10.17487/RFC5722, December 2009,
<https://www.rfc-editor.org/info/rfc5722>.
[RFC6946] Gont, F., "Processing of IPv6 "Atomic" Fragments",
RFC 6946, DOI 10.17487/RFC6946, May 2013,
<https://www.rfc-editor.org/info/rfc6946>.
[RFC6980] Gont, F., "Security Implications of IPv6 Fragmentation
with IPv6 Neighbor Discovery", RFC 6980,
DOI 10.17487/RFC6980, August 2013,
<https://www.rfc-editor.org/info/rfc6980>.
[RFC7112] Gont, F., Manral, V., and R. Bonica, "Implications of
Oversized IPv6 Header Chains", RFC 7112,
DOI 10.17487/RFC7112, January 2014,
<https://www.rfc-editor.org/info/rfc7112>.
[RFC8021] Gont, F., Liu, W., and T. Anderson, "Generation of IPv6
Atomic Fragments Considered Harmful", RFC 8021,
DOI 10.17487/RFC8021, January 2017,
<https://www.rfc-editor.org/info/rfc8021>.
[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>.
[RFC8504] Chown, T., Loughney, J., and T. Winters, "IPv6 Node
Requirements", BCP 220, RFC 8504, DOI 10.17487/RFC8504,
January 2019, <https://www.rfc-editor.org/info/rfc8504>.
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9.2. Informative References
[APNIC-Scudder]
Scudder, J., "Modern router architecture and IPv6", APNIC
Blog, June 4, 2020, <https://blog.apnic.net/2020/06/04/
modern-router-architecture-and-ipv6/>.
[Atlasis2012]
Atlasis, A., "Attacking IPv6 Implementation Using
Fragmentation", BlackHat Europe 2012. Amsterdam,
Netherlands. March 14-16, 2012,
<https://media.blackhat.com/bh-eu-12/Atlasis/bh-eu-12-
Atlasis-Attacking_IPv6-Slides.pdf>.
[Atlasis2014]
Atlasis, A., "A Novel Way of Abusing IPv6 Extension
Headers to Evade IPv6 Security Devices", May 2014,
<http://www.insinuator.net/2014/05/a-novel-way-of-abusing-
ipv6-extension-headers-to-evade-ipv6-security-devices/>.
[BH-EU-2014]
Atlasis, A., Rey, E., and R. Schaefer, "Evasion of High-
End IDPS Devices at the IPv6 Era", BlackHat Europe 2014,
2014, <https://www.ernw.de/download/eu-14-Atlasis-Rey-
Schaefer-briefings-Evasion-of-HighEnd-IPS-Devices-wp.pdf>.
[Bonica-NANOG58]
Bonica, R., "IPv6 Extension Headers in the Real World
v2.0", NANOG 58. New Orleans, Louisiana, USA. June 3-5,
2013, <https://www.nanog.org/sites/default/files/
mon.general.fragmentation.bonica.pdf>.
[Cisco-EH-Cons]
Cisco, "IPv6 Extension Headers Review and Considerations",
October 2006,
<http://www.cisco.com/en/US/technologies/tk648/tk872/
technologies_white_paper0900aecd8054d37d.pdf>.
[Gont-Chown-IEPG89]
Gont, F. and T. Chown, "A Small Update on the Use of IPv6
Extension Headers", IEPG 89. London, UK. March 2, 2014,
<http://www.iepg.org/2014-03-02-ietf89/fgont-iepg-ietf89-
eh-update.pdf>.
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[Gont-IEPG88]
Gont, F., "Fragmentation and Extension header Support in
the IPv6 Internet", IEPG 88. Vancouver, BC, Canada.
November 13, 2013, <http://www.iepg.org/2013-11-ietf88/
fgont-iepg-ietf88-ipv6-frag-and-eh.pdf>.
[Huston-2017]
Huston, G., "Dealing with IPv6 fragmentation in the
DNS", APNIC Blog, 2017,
<https://blog.apnic.net/2017/08/22/dealing-ipv6-
fragmentation-dns/>.
[I-D.ietf-intarea-frag-fragile]
Bonica, R., Baker, F., Huston, G., Hinden, R., Troan, O.,
and F. Gont, "IP Fragmentation Considered Fragile", draft-
ietf-intarea-frag-fragile-17 (work in progress), September
2019.
[I-D.ietf-opsec-ipv6-eh-filtering]
Gont, F. and W. LIU, "Recommendations on the Filtering of
IPv6 Packets Containing IPv6 Extension Headers", draft-
ietf-opsec-ipv6-eh-filtering-06 (work in progress), July
2018.
[I-D.kampanakis-6man-ipv6-eh-parsing]
Kampanakis, P., "Implementation Guidelines for parsing
IPv6 Extension Headers", draft-kampanakis-6man-ipv6-eh-
parsing-01 (work in progress), August 2014.
[I-D.taylor-v6ops-fragdrop]
Jaeggli, J., Colitti, L., Kumari, W., Vyncke, E., Kaeo,
M., and T. Taylor, "Why Operators Filter Fragments and
What It Implies", draft-taylor-v6ops-fragdrop-02 (work in
progress), December 2013.
[]
Kumari, W., Jaeggli, J., Bonica, R., and J. Linkova,
"Operational Issues Associated With Long IPv6 Header
Chains", draft-wkumari-long-headers-03 (work in progress),
June 2015.
[IEPG94-Scudder]
Petersen, B. and J. Scudder, "Modern Router Architecture
for Protocol Designers", IEPG 94. Yokohama, Japan.
November 1, 2015, <http://www.iepg.org/2015-11-01-ietf94/
IEPG-RouterArchitecture-jgs.pdf>.
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[Linkova-Gont-IEPG90]
Linkova, J. and F. Gont, "IPv6 Extension Headers in the
Real World v2.0", IEPG 90. Toronto, ON, Canada. July 20,
2014, <http://www.iepg.org/2014-07-20-ietf90/iepg-
ietf90-ipv6-ehs-in-the-real-world-v2.0.pdf>.
[PMTUD-Blackholes]
De Boer, M. and J. Bosma, "Discovering Path MTU black
holes on the Internet using RIPE Atlas", July 2012,
<http://www.nlnetlabs.nl/downloads/publications/pmtu-
black-holes-msc-thesis.pdf>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<https://www.rfc-editor.org/info/rfc5575>.
[RFC5635] Kumari, W. and D. McPherson, "Remote Triggered Black Hole
Filtering with Unicast Reverse Path Forwarding (uRPF)",
RFC 5635, DOI 10.17487/RFC5635, August 2009,
<https://www.rfc-editor.org/info/rfc5635>.
[RFC6192] Dugal, D., Pignataro, C., and R. Dunn, "Protecting the
Router Control Plane", RFC 6192, DOI 10.17487/RFC6192,
March 2011, <https://www.rfc-editor.org/info/rfc6192>.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437,
DOI 10.17487/RFC6437, November 2011,
<https://www.rfc-editor.org/info/rfc6437>.
[RFC6438] Carpenter, B. and S. Amante, "Using the IPv6 Flow Label
for Equal Cost Multipath Routing and Link Aggregation in
Tunnels", RFC 6438, DOI 10.17487/RFC6438, November 2011,
<https://www.rfc-editor.org/info/rfc6438>.
[RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing
of IPv6 Extension Headers", RFC 7045,
DOI 10.17487/RFC7045, December 2013,
<https://www.rfc-editor.org/info/rfc7045>.
[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>.
Gont, et al. Expires January 26, 2021 [Page 13]
Internet-Draft IPv6 Extension Headers July 2020
[RFC7739] Gont, F., "Security Implications of Predictable Fragment
Identification Values", RFC 7739, DOI 10.17487/RFC7739,
February 2016, <https://www.rfc-editor.org/info/rfc7739>.
[RFC7872] Gont, F., Linkova, J., Chown, T., and W. Liu,
"Observations on the Dropping of Packets with IPv6
Extension Headers in the Real World", RFC 7872,
DOI 10.17487/RFC7872, June 2016,
<https://www.rfc-editor.org/info/rfc7872>.
[Zack-FW-Benchmark]
Zack, E., "Firewall Security Assessment and Benchmarking
IPv6 Firewall Load Tests", IPv6 Hackers Meeting #1,
Berlin, Germany. June 30, 2013,
<http://www.ipv6hackers.org/meetings/ipv6-hackers-1/zack-
ipv6hackers1-firewall-security-assessment-and-
benchmarking.pdf>.
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
Nick Hilliard
INEX
4027 Kingswood Road
Dublin 24
IE
Email: nick@inex.ie
Gert Doering
SpaceNet AG
Joseph-Dollinger-Bogen 14
Muenchen D-80807
Germany
Email: gert@space.net
Gont, et al. Expires January 26, 2021 [Page 14]
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Warren Kumari
Google
1600 Amphitheatre Parkway
Mountain View, CA 94043
US
Email: warren@kumari.net
Geoff Huston
Email: gih@apnic.net
URI: http://www.apnic.net
Gont, et al. Expires January 26, 2021 [Page 15]