draft-ietf-grow-blackholing-03.txt   rfc7999.txt 
Network Working Group T. King Internet Engineering Task Force (IETF) T. King
Internet-Draft C. Dietzel Request for Comments: 7999 C. Dietzel
Intended status: Informational DE-CIX Management GmbH Category: Informational DE-CIX
Expires: February 13, 2017 J. Snijders ISSN: 2070-1721 J. Snijders
NTT NTT
G. Doering G. Doering
SpaceNet AG SpaceNet AG
G. Hankins G. Hankins
Nokia Nokia
August 12, 2016 October 2016
BLACKHOLE BGP Community for Blackholing BLACKHOLE Community
draft-ietf-grow-blackholing-03
Abstract Abstract
This document describes the use of a well-known Border Gateway This document describes the use of a well-known Border Gateway
Protocol (BGP) community for destination-based blackholing in IP Protocol (BGP) community for destination-based blackholing in IP
networks. This well-known advisory transitive BGP community named networks. This well-known advisory transitive BGP community named
BLACKHOLE allows an origin AS to specify that a neighboring network "BLACKHOLE" allows an origin Autonomous System (AS) to specify that a
should discard any traffic destined towards the tagged IP prefix. neighboring network should discard any traffic destined towards the
tagged IP prefix.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
be interpreted as described in [RFC2119] only when they appear in all
upper case. They may also appear in lower or mixed case as English
words, without normative meaning.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for informational purposes.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
This Internet-Draft will expire on February 13, 2017. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7999.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction ....................................................3
2. BLACKHOLE Community . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language ......................................3
3. Operational Recommendations . . . . . . . . . . . . . . . . . 3 2. BLACKHOLE Community .............................................4
3.1. IP Prefix Announcements with BLACKHOLE Community Attached 3 3. Operational Recommendations .....................................4
3.2. Local Scope of Blackholes . . . . . . . . . . . . . . . . 4 3.1. IP Prefix Announcements with BLACKHOLE Community Attached ..4
3.3. Accepting Blackholed IP Prefixes . . . . . . . . . . . . 4 3.2. Local Scope of Blackholes ..................................4
4. Vendor Implementation Recommendations . . . . . . . . . . . . 5 3.3. Accepting Blackholed IP Prefixes ...........................5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 4. Vendor Implementation Recommendations ...........................6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations .............................................6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations .........................................6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6 7. References ......................................................7
7.2. Informative References . . . . . . . . . . . . . . . . . 6 7.1. Normative References .......................................7
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 7 7.2. Informative References .....................................7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Acknowledgements ...................................................8
Authors' Addresses .................................................9
1. Introduction 1. Introduction
Network infrastructures have been increasingly hampered by DDoS Network infrastructures have been increasingly hampered by DDoS
attacks. In order to dampen the effects of these DDoS attacks, IP attacks. In order to dampen the effects of these DDoS attacks, IP
networks have offered blackholing with BGP [RFC4271] using various networks have offered blackholing with BGP [RFC4271] using various
mechanisms such as those described in [RFC3882] and [RFC5635]. mechanisms such as those described in [RFC3882] and [RFC5635].
DDoS attacks targeting a certain IP address may cause congestion of DDoS attacks targeting a certain IP address may cause congestion of
links used to connect to adjacent networks. In order to limit the links used to connect to adjacent networks. In order to limit the
impact of such a scenario on legitimate traffic, networks adopted a impact of such a scenario on legitimate traffic, networks adopted a
mechanism called BGP blackholing. A network that wants to trigger mechanism called "BGP blackholing". A network that wants to trigger
blackholing needs to understand the triggering mechanism adopted by blackholing needs to understand the triggering mechanism adopted by
its neighboring networks. Different networks provide different its neighboring networks. Different networks provide different
mechanisms to trigger blackholing, including but not limited to pre- mechanisms to trigger blackholing, including but not limited to pre-
defined blackhole next-hop IP addresses, specific BGP communities or defined blackhole next-hop IP addresses, specific BGP communities, or
via an out-of-band BGP session with a special BGP speaker. out-of-band BGP sessions with a special BGP speaker.
Having several different mechanisms to trigger blackholing in Having several different mechanisms to trigger blackholing in
different networks makes it an unnecessarily complex, error-prone and different networks makes it an unnecessarily complex, error-prone,
cumbersome task for network operators. Therefore, a well-known BGP and cumbersome task for network operators. Therefore, a well-known
community [RFC1997] is defined for operational ease. BGP community [RFC1997] is defined for operational ease.
Having such a well-known BGP community for blackholing also further Having such a well-known BGP community for blackholing also further
simplifies network operations because: simplifies network operations because:
o Implementing and monitoring blackholing becomes easier when o Implementing and monitoring blackholing becomes easier when
implementation, and operational guides do not cover many implementation and operational guides do not cover many variations
variations to trigger blackholing. to trigger blackholing.
o The number of support requests from customers about how to trigger o The number of support requests from customers about how to trigger
blackholing in a particular neighboring network will be reduced as blackholing in a particular neighboring network will be reduced as
the codepoint for common blackholing mechanisms is unified and the codepoint for common blackholing mechanisms is unified and
well-known. well-known.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
be interpreted as described in [RFC2119] only when they appear in all
upper case. They may also appear in lower case or mixed case as
English words, without normative meaning.
2. BLACKHOLE Community 2. BLACKHOLE Community
This document defines the use of a new well-known BGP transitive This document defines the use of a new well-known BGP transitive
community, BLACKHOLE. community, BLACKHOLE.
The semantics of this community allow a network to interpret the The semantics of this community allow a network to interpret the
presence of this community as an advisory qualification to drop any presence of this community as an advisory qualification to drop any
traffic being sent towards this prefix. traffic being sent towards this prefix.
3. Operational Recommendations 3. Operational Recommendations
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be agreed upon by the two networks before advertising it. In a be agreed upon by the two networks before advertising it. In a
multilateral peering relationship, the decision to honor or ignore multilateral peering relationship, the decision to honor or ignore
the BLACKHOLE community is to be made according to the operator's the BLACKHOLE community is to be made according to the operator's
routing policy. The community SHOULD be ignored, if it is received routing policy. The community SHOULD be ignored, if it is received
by a network that it not using it. by a network that it not using it.
When a network is under DDoS duress, it MAY announce an IP prefix When a network is under DDoS duress, it MAY announce an IP prefix
covering the victim's IP address(es) for the purpose of signaling to covering the victim's IP address(es) for the purpose of signaling to
neighboring networks that any traffic destined for these IP neighboring networks that any traffic destined for these IP
address(es) should be discarded. In such a scenario, the network address(es) should be discarded. In such a scenario, the network
operator SHOULD attach the BLACKHOLE BGP community. operator SHOULD attach the BLACKHOLE community.
The BLACKHOLE community MAY also be used as one of the trigger The BLACKHOLE community MAY also be used as one of the trigger
communities in a [RFC5635] destination-based RTBH configuration. communities in a destination-based Remote Triggered Blackhole (RTBH)
[RFC5635] configuration.
3.2. Local Scope of Blackholes 3.2. Local Scope of Blackholes
A BGP speaker receiving an announcement tagged with the BLACKHOLE A BGP speaker receiving an announcement tagged with the BLACKHOLE
community SHOULD add the NO_ADVERTISE or NO_EXPORT community as community SHOULD add the NO_ADVERTISE or NO_EXPORT community as
defined in [RFC1997], or a similar community to prevent propagation defined in [RFC1997], or a similar community, to prevent propagation
of the prefix outside the local AS. The community to prevent of the prefix outside the local AS. The community to prevent
propagation SHOULD be chosen according to the operator's routing propagation SHOULD be chosen according to the operator's routing
policy. policy.
Unintentional leaking of more specific IP prefixes to neighboring Unintentional leaking of more specific IP prefixes to neighboring
networks can have adverse effects. Extreme caution should be used networks can have adverse effects. Extreme caution should be used
when purposefully propagating IP prefixes tagged with the BLACKHOLE when purposefully propagating IP prefixes tagged with the BLACKHOLE
BGP community outside the local routing domain, unless policy community outside the local routing domain, unless policy explicitly
explicitly aims at doing just that. aims at doing just that.
3.3. Accepting Blackholed IP Prefixes 3.3. Accepting Blackholed IP Prefixes
It has been observed in provider networks running BGP that It has been observed in provider networks running BGP that
announcements of IP prefixes longer than /24 for IPv4 and /48 for announcements of IP prefixes longer than /24 for IPv4 and /48 for
IPv6 are usually not accepted on the Internet (see section 6.1.3 IPv6 are usually not accepted on the Internet (see Section 6.1.3 of
[RFC7454]). However, blackhole prefix length should be as long as [RFC7454]). However, blackhole prefix length should be as long as
possible in order to limit the impact of discarding traffic for possible in order to limit the impact of discarding traffic for
adjacent IP space that is not under DDoS duress. The blackhole adjacent IP space that is not under DDoS duress. The blackhole
prefix length is typically as specific as possible, a /32 for IPv4 or prefix length is typically as specific as possible, /32 for IPv4 or
a /128 for IPv6. /128 for IPv6.
BGP speakers in a bilateral peering relationship using the BLACKHOLE BGP speakers in a bilateral peering relationship using the BLACKHOLE
community MUST only accept and honor BGP announcements carrying the community MUST only accept and honor BGP announcements carrying the
BLACKHOLE community under the two following conditions: BLACKHOLE community under the two following conditions:
o the announced prefix is covered by an equal or shorter prefix that o The announced prefix is covered by an equal or shorter prefix that
the neighboring network is authorized to advertise. the neighboring network is authorized to advertise.
o the receiving party agreed to honor the BLACKHOLE community on the
particular BGP session o The receiving party agreed to honor the BLACKHOLE community on the
particular BGP session.
In topologies with a route server or other multilateral peering In topologies with a route server or other multilateral peering
relationships, BGP speakers SHOULD accept and honor BGP announcements relationships, BGP speakers SHOULD accept and honor BGP announcements
under the same conditions. under the same conditions.
An operator MUST ensure that origin validation techniques (such as An operator MUST ensure that origin validation techniques (such as
[RFC6811]) do not inadvertently block legitimate announcements the one described in [RFC6811]) do not inadvertently block legitimate
carrying the BLACKHOLE community. announcements carrying the BLACKHOLE community.
The BLACKHOLE community is not intended to be used with [RFC5575] The BLACKHOLE community is not intended to be used with Network Layer
NLRI to distribute traffic flow specifications. Reachability Information (NLRI) [RFC5575] to distribute traffic flow
specifications.
The error handling for this community follows the process in The error handling for this community follows the process in
[RFC7606] that causes a malformed community to be treated as a [RFC7606] that causes a malformed community to be treated as
withdrawn. withdrawn.
Operators are encouraged to store all BGP updates in their network Operators are encouraged to store all BGP updates in their network
carrying the BLACKHOLE community for long term analysis or internal carrying the BLACKHOLE community for long-term analysis or internal
audit purposes. audit purposes.
4. Vendor Implementation Recommendations 4. Vendor Implementation Recommendations
Without an explicit configuration directive set by the operator, Without an explicit configuration directive set by the operator,
network elements SHOULD NOT discard traffic destined towards IP network elements SHOULD NOT discard traffic destined towards IP
prefixes which are tagged with the BLACKHOLE BGP community. The prefixes that are tagged with the BLACKHOLE community. The operator
operator is expected to explicitly configure the network element to is expected to explicitly configure the network element to honor the
honor the BLACKHOLE BGP community in a way that is compliant with the BLACKHOLE community in a way that is compliant with the operator's
operator's routing policy. routing policy.
Vendors MAY provide a shorthand keyword in their configuration Vendors MAY provide a shorthand keyword in their configuration
language to reference the well-known BLACKHOLE BGP community language to reference the well-known BLACKHOLE community attribute
attribute value. The suggested string to be used is "blackhole". value. The suggested string to be used is "blackhole".
5. IANA Considerations 5. IANA Considerations
The IANA is requested to register BLACKHOLE as a well-known BGP The IANA has registered BLACKHOLE in the "BGP Well-known Communities"
community with global significance: registry.
BLACKHOLE (= 0xFFFF029A) BLACKHOLE (= 0xFFFF029A)
The low-order two octets in decimal are 666, a value commonly The low-order two octets in decimal are 666, a value commonly
associated with BGP blackholing among network operators. associated with BGP blackholing among network operators.
6. Security Considerations 6. Security Considerations
BGP contains no specific mechanism to prevent the unauthorized BGP contains no specific mechanism to prevent the unauthorized
modification of information by the forwarding agent. This allows modification of information by the forwarding agent. This allows
routing information to be modified, removed, or false information to routing information to be modified or removed; it also allows false
be added by forwarding agents. Recipients of routing information are information to be added by forwarding agents. Recipients of routing
not able to detect this modification. BGPSec information are not able to detect this modification. BGPsec
[I-D.ietf-sidr-bgpsec-protocol] does not resolve this situation. [BGPSEC] does not resolve this situation. Even when BGPsec is in
Even when BGPSec is in place, a forwarding agent can alter, add or place, a forwarding agent can alter, add, or remove BGP communities.
remove BGP communities.
The unauthorized addition of the BLACKHOLE BGP community to an IP The unauthorized addition of the BLACKHOLE community to an IP prefix
prefix by an adversary may cause a denial of service attack based on by an adversary may cause a denial-of-service attack based on denial
denial of reachability. of reachability.
In order to further limit the impact of unauthorized BGP In order to further limit the impact of unauthorized BGP
announcements carrying the BLACKHOLE BGP community, the receiving BGP announcements carrying the BLACKHOLE community, the receiving BGP
speaker SHOULD verify by applying strict filtering (see section speaker SHOULD verify by applying strict filtering (see
6.2.1.1.2 [RFC7454]) that the peer announcing the prefix is Section 6.2.1.1.2 of [RFC7454]) that the peer announcing the prefix
authorized to do so. If not, the BGP announcement should be is authorized to do so. If not, the BGP announcement should be
filtered. filtered.
BGP announcements carrying the BLACKHOLE community should only be BGP announcements carrying the BLACKHOLE community should only be
accepted and honored, if the neighboring network is authorized to accepted and honored if the neighboring network is authorized to
advertise the prefix. The method of validating announcements is to advertise the prefix. The method of validating announcements is to
be chosen according to the operator's routing policy. be chosen according to the operator's routing policy.
It is RECOMMENDED that operators use best common practices to protect It is RECOMMENDED that operators use best common practices to protect
their BGP sessions, such as the ones in [RFC7454]. their BGP sessions, such as the ones in [RFC7454].
7. References 7. References
7.1. Normative References 7.1. Normative References
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DOI 10.17487/RFC4271, January 2006, DOI 10.17487/RFC4271, January 2006,
<http://www.rfc-editor.org/info/rfc4271>. <http://www.rfc-editor.org/info/rfc4271>.
[RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K. [RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
Patel, "Revised Error Handling for BGP UPDATE Messages", Patel, "Revised Error Handling for BGP UPDATE Messages",
RFC 7606, DOI 10.17487/RFC7606, August 2015, RFC 7606, DOI 10.17487/RFC7606, August 2015,
<http://www.rfc-editor.org/info/rfc7606>. <http://www.rfc-editor.org/info/rfc7606>.
7.2. Informative References 7.2. Informative References
[I-D.ietf-sidr-bgpsec-protocol] [BGPSEC] Lepinski, M., Ed. and K. Sriram, Ed., "BGPsec Protocol
Lepinski, M. and K. Sriram, "BGPsec Protocol Specification", Work in Progress, draft-ietf-sidr-bgpsec-
Specification", draft-ietf-sidr-bgpsec-protocol-17 (work protocol-18, August 2016.
in progress), June 2016.
[RFC3882] Turk, D., "Configuring BGP to Block Denial-of-Service [RFC3882] Turk, D., "Configuring BGP to Block Denial-of-Service
Attacks", RFC 3882, DOI 10.17487/RFC3882, September 2004, Attacks", RFC 3882, DOI 10.17487/RFC3882, September 2004,
<http://www.rfc-editor.org/info/rfc3882>. <http://www.rfc-editor.org/info/rfc3882>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J., [RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009, Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<http://www.rfc-editor.org/info/rfc5575>. <http://www.rfc-editor.org/info/rfc5575>.
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[RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R. [RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
Austein, "BGP Prefix Origin Validation", RFC 6811, Austein, "BGP Prefix Origin Validation", RFC 6811,
DOI 10.17487/RFC6811, January 2013, DOI 10.17487/RFC6811, January 2013,
<http://www.rfc-editor.org/info/rfc6811>. <http://www.rfc-editor.org/info/rfc6811>.
[RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations [RFC7454] Durand, J., Pepelnjak, I., and G. Doering, "BGP Operations
and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454, and Security", BCP 194, RFC 7454, DOI 10.17487/RFC7454,
February 2015, <http://www.rfc-editor.org/info/rfc7454>. February 2015, <http://www.rfc-editor.org/info/rfc7454>.
Appendix A. Acknowledgements Acknowledgements
The authors would like to gratefully acknowledge many people who have The authors would like to gratefully acknowledge many people who have
contributed discussions and ideas to the making of this proposal. contributed discussions and ideas to the development of this
They include Petr Jiran, Yordan Kritski, Christian Seitz, Nick document. They include Petr Jiran, Yordan Kritski, Christian Seitz,
Hilliard, Joel Jaeggli, Christopher Morrow, Thomas Mangin, Will Nick Hilliard, Joel Jaeggli, Christopher Morrow, Thomas Mangin, Will
Hargrave, Niels Bakker, David Farmer, Jared Mauch, John Heasley and Hargrave, Niels Bakker, David Farmer, Jared Mauch, John Heasley, and
Terry Manderson. Terry Manderson.
Authors' Addresses Authors' Addresses
Thomas King Thomas King
DE-CIX Management GmbH DE-CIX Management GmbH
Lichtstrasse 43i Lichtstrasse 43i
Cologne 50825 Cologne 50825
Germany Germany
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Email: thomas.king@de-cix.net Email: thomas.king@de-cix.net
Christoph Dietzel Christoph Dietzel
DE-CIX Management GmbH DE-CIX Management GmbH
Lichtstrasse 43i Lichtstrasse 43i
Cologne 50825 Cologne 50825
Germany Germany
Email: christoph.dietzel@de-cix.net Email: christoph.dietzel@de-cix.net
Job Snijders Job Snijders
NTT Communications NTT Communications
Theodorus Majofskistraat 100 Theodorus Majofskistraat 100
Amsterdam 1065 SZ Amsterdam 1065 SZ
NL The Netherlands
Email: job@ntt.net Email: job@ntt.net
Gert Doering Gert Doering
SpaceNet AG SpaceNet AG
Joseph-Dollinger-Bogen 14 Joseph-Dollinger-Bogen 14
Munich 80807 Munich 80807
Germany Germany
Email: gert@space.net Email: gert@space.net
Greg Hankins Greg Hankins
Nokia Nokia
777 E. Middlefield Road 777 E. Middlefield Road
Mountain View, CA 94043 Mountain View, CA 94043
USA United States of America
Email: greg.hankins@nokia.com Email: greg.hankins@nokia.com
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