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
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	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
	skipping to change at page 3, line 48 ¶		skipping to change at page 4, line 32 ¶
	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
	skipping to change at page 6, line 42 ¶		skipping to change at page 7, line 38 ¶
	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>.
	skipping to change at page 7, line 24 ¶		skipping to change at page 8, line 19 ¶
	[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
	skipping to change at page 8, line 4 ¶		skipping to change at page 9, line 22 ¶
	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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