draft-ietf-grow-blackholing-02.txt		draft-ietf-grow-blackholing-03.txt
	Network Working Group T. King		Network Working Group T. King
	Internet-Draft C. Dietzel		Internet-Draft C. Dietzel
	Intended status: Informational DE-CIX Management GmbH		Intended status: Informational DE-CIX Management GmbH
	Expires: January 2, 2017 J. Snijders		Expires: February 13, 2017 J. Snijders
	NTT		NTT
	G. Doering		G. Doering
	SpaceNet AG		SpaceNet AG
	G. Hankins		G. Hankins
	Nokia		Nokia
	July 1, 2016		August 12, 2016
	BLACKHOLE BGP Community for Blackholing		BLACKHOLE BGP Community for Blackholing
	draft-ietf-grow-blackholing-02		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, namely		networks. This well-known advisory transitive BGP community named
	BLACKHOLE, allows an origin AS to specify that a neighboring network		BLACKHOLE allows an origin AS to specify that a neighboring network
	should discard any traffic destined towards the tagged IP prefix.		should discard any traffic destined towards the tagged IP prefix.
	Requirements Language		Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to
	be interpreted as described in [RFC2119] only when they appear in all		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		upper case. They may also appear in lower or mixed case as English
	words, without normative meaning.		words, without normative meaning.
	skipping to change at page 1, line 48 ¶		skipping to change at page 1, line 48 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on January 2, 2017.		This Internet-Draft will expire on February 13, 2017.
	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 . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. BLACKHOLE Attribute . . . . . . . . . . . . . . . . . . . . . 3		2. BLACKHOLE Community . . . . . . . . . . . . . . . . . . . . . 3
	3. Operational Recommendations . . . . . . . . . . . . . . . . . 3		3. Operational Recommendations . . . . . . . . . . . . . . . . . 3
	3.1. IP Prefix Announcements with BLACKHOLE Community Attached 3		3.1. IP Prefix Announcements with BLACKHOLE Community Attached 3
	3.2. Local Scope of Blackholes . . . . . . . . . . . . . . . . 3		3.2. Local Scope of Blackholes . . . . . . . . . . . . . . . . 4
	3.3. Accepting Blackholed IP Prefixes . . . . . . . . . . . . 4		3.3. Accepting Blackholed IP Prefixes . . . . . . . . . . . . 4
	4. Vendor Implementation Recommendations . . . . . . . . . . . . 4		4. Vendor Implementation Recommendations . . . . . . . . . . . . 5
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
	6. Security Considerations . . . . . . . . . . . . . . . . . . . 4		6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
	7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5		7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
	7.1. Normative References . . . . . . . . . . . . . . . . . . 5		7.1. Normative References . . . . . . . . . . . . . . . . . . 6
	7.2. Informative References . . . . . . . . . . . . . . . . . 5		7.2. Informative References . . . . . . . . . . . . . . . . . 6
	Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 6		Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 7
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
	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 BGP blackholing to neighboring networks via		networks have offered blackholing with BGP [RFC4271] using various
	various mechanisms such as 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 other 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.		via an out-of-band BGP session 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 and
	cumbersome task for network operators. Therefore a well-known BGP		cumbersome task for network operators. Therefore, a well-known BGP
	community [RFC1997] is defined for operational ease.		community [RFC1997] is defined for operational ease.
	Having such a well-known BGP community for blackholing also supports		Having such a well-known BGP community for blackholing also further
	networks 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 options		implementation, and operational guides do not cover many
	that trigger blackholing.		variations 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.		the codepoint for common blackholing mechanisms is unified and
			well-known.
	Making it considerably easier for network operators to utilize
	blackholing makes operations easier.
	2. BLACKHOLE Attribute		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 attribute 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
	3.1. IP Prefix Announcements with BLACKHOLE Community Attached		3.1. IP Prefix Announcements with BLACKHOLE Community Attached
			Accepting and honoring the BLACKHOLE community, or ignoring it, is a
			choice that is made by each operator. This community MAY be used in
			all bilateral and multilateral BGP deployment scenarios. In a
			bilateral peering relationship, use of the BLACKHOLE community MUST
			be agreed upon by the two networks before advertising it. In a
			multilateral peering relationship, the decision to honor or ignore
			the BLACKHOLE community is to be made according to the operator's
			routing policy. The community SHOULD be ignored, if it is received
			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 BLACKHOLE BGP community.		operator SHOULD attach the BLACKHOLE BGP community.
			The BLACKHOLE community MAY also be used as one of the trigger
			communities in a [RFC5635] destination-based RTBH configuration.
	3.2. Local Scope of Blackholes		3.2. Local Scope of Blackholes
	A BGP speaker receiving a BGP announcement tagged with the BLACKHOLE		A BGP speaker receiving an announcement tagged with the BLACKHOLE
	BGP community SHOULD add a NO_ADVERTISE, NO_EXPORT or similar		community SHOULD add the NO_ADVERTISE or NO_EXPORT community as
	community to prevent propagation of this route outside the local AS.		defined in [RFC1997], or a similar community to prevent propagation
			of the prefix outside the local AS. The community to prevent
			propagation SHOULD be chosen according to the operator's routing
			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.		BGP community outside the local routing domain, unless policy
			explicitly aims at doing just that.
	3.3. Accepting Blackholed IP Prefixes		3.3. Accepting Blackholed IP Prefixes
	It has been observed that announcements of IP prefixes larger than		It has been observed in provider networks running BGP that
	/24 for IPv4 and /48 for IPv6 are usually not accepted on the		announcements of IP prefixes longer than /24 for IPv4 and /48 for
	Internet (see section 6.1.3 [RFC7454]). However, blackhole routes		IPv6 are usually not accepted on the Internet (see section 6.1.3
	should be as small as possible in order to limit the impact of		[RFC7454]). However, blackhole prefix length should be as long as
	discarding traffic for adjacent IP space that is not under DDoS		possible in order to limit the impact of discarding traffic for
	duress. Typically, the blackhole route's prefix length is as		adjacent IP space that is not under DDoS duress. The blackhole
	specific as /32 for IPv4 and /128 for IPv6.		prefix length is typically as specific as possible, a /32 for IPv4 or
			a /128 for IPv6.
	BGP speakers SHOULD only accept and honor BGP announcements carrying		BGP speakers in a bilateral peering relationship using the BLACKHOLE
	the BLACKHOLE community if the announced prefix is covered by a		community MUST only accept and honor BGP announcements carrying the
	shorter prefix for which the neighboring network is authorized to		BLACKHOLE community under the two following conditions:
	advertise.
			o the announced prefix is covered by an equal or shorter prefix that
			the neighboring network is authorized to advertise.
			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
			relationships, BGP speakers SHOULD accept and honor BGP announcements
			under the same conditions.
			An operator MUST ensure that origin validation techniques (such as
			[RFC6811]) do not inadvertently block legitimate announcements
			carrying the BLACKHOLE community.
			The BLACKHOLE community is not intended to be used with [RFC5575]
			NLRI to distribute traffic flow specifications.
			The error handling for this community follows the process in
			[RFC7606] that causes a malformed community to be treated as a
			withdrawn.
			Operators are encouraged to store all BGP updates in their network
			carrying the BLACKHOLE community for long term analysis or internal
			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 which are tagged with the BLACKHOLE BGP community. The
	operator is expected to explicitly configure the network element to		operator is expected to explicitly configure the network element to
	honor the BLACKHOLE BGP community in a way that is compliant with the		honor the BLACKHOLE BGP community in a way that is compliant with the
	operator's routing policy.		operator's routing policy.
	Vendors MAY provide a short-hand 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 BGP community
	attribute value. The suggested string to be used is "blackhole".		attribute 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 is requested to register BLACKHOLE as a well-known BGP
	community with global significance:		community with global significance:
	BLACKHOLE (= 0xFFFF029A)		BLACKHOLE (= 0xFFFF029A)
	The low-order two octets in decimal are 666, amongst network		The low-order two octets in decimal are 666, a value commonly
	operators a value commonly associated with BGP blackholing.		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, removed, or false information to
	be added by forwarding agents. Recipients of routing information are		be added by forwarding agents. Recipients of routing information are
	not able to detect this modification. Also, RPKI [RFC6810] and		not able to detect this modification. BGPSec
	BGPSec [I-D.ietf-sidr-bgpsec-overview] do not fully resolve this		[I-D.ietf-sidr-bgpsec-protocol] does not resolve this situation.
	situation. For instance, BGP communities can still be added or		Even when BGPSec is in place, a forwarding agent can alter, add or
	altered by a forwarding agent even if RPKI and BGPSec are in place.		remove BGP communities.
	The unauthorized addition of the BLACKHOLE BGP community to an IP		The unauthorized addition of the BLACKHOLE BGP community to an IP
	prefix by an adversery may cause a denial of service attack based on		prefix by an adversary may cause a denial of service attack based on
	denial of reachability.		denial 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 BGP community, the receiving BGP
	speaker SHOULD verify by applying strict filtering (see section		speaker SHOULD verify by applying strict filtering (see section
	6.2.1.1.2. [RFC7454]) that the peer announcing the prefix is		6.2.1.1.2 [RFC7454]) that the peer announcing the prefix is
	authorized to do so. If not, the BGP announcement should be filtered		authorized to do so. If not, the BGP announcement should be
	out.		filtered.
			BGP announcements carrying the BLACKHOLE community should only be
			accepted and honored, if the neighboring network is authorized to
			advertise the prefix. The method of validating announcements is to
			be chosen according to the operator's routing policy.
			It is RECOMMENDED that operators use best common practices to protect
			their BGP sessions, such as the ones in [RFC7454].
	7. References		7. References
	7.1. Normative References		7.1. Normative References
	[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities		[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities
	Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,		Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
	<http://www.rfc-editor.org/info/rfc1997>.		<http://www.rfc-editor.org/info/rfc1997>.
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<http://www.rfc-editor.org/info/rfc2119>.		<http://www.rfc-editor.org/info/rfc2119>.
			[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
			Border Gateway Protocol 4 (BGP-4)", RFC 4271,
			DOI 10.17487/RFC4271, January 2006,
			<http://www.rfc-editor.org/info/rfc4271>.
			[RFC7606] Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
			Patel, "Revised Error Handling for BGP UPDATE Messages",
			RFC 7606, DOI 10.17487/RFC7606, August 2015,
			<http://www.rfc-editor.org/info/rfc7606>.
	7.2. Informative References		7.2. Informative References
	[I-D.ietf-sidr-bgpsec-overview]		[I-D.ietf-sidr-bgpsec-protocol]
	Lepinski, M. and S. Turner, "An Overview of BGPsec",		Lepinski, M. and K. Sriram, "BGPsec Protocol
	draft-ietf-sidr-bgpsec-overview-08 (work in progress),		Specification", draft-ietf-sidr-bgpsec-protocol-17 (work
	June 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.,
			and D. McPherson, "Dissemination of Flow Specification
			Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
			<http://www.rfc-editor.org/info/rfc5575>.
	[RFC5635] Kumari, W. and D. McPherson, "Remote Triggered Black Hole		[RFC5635] Kumari, W. and D. McPherson, "Remote Triggered Black Hole
	Filtering with Unicast Reverse Path Forwarding (uRPF)",		Filtering with Unicast Reverse Path Forwarding (uRPF)",
	RFC 5635, DOI 10.17487/RFC5635, August 2009,		RFC 5635, DOI 10.17487/RFC5635, August 2009,
	<http://www.rfc-editor.org/info/rfc5635>.		<http://www.rfc-editor.org/info/rfc5635>.
	[RFC6810] Bush, R. and R. Austein, "The Resource Public Key		[RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
	Infrastructure (RPKI) to Router Protocol", RFC 6810,		Austein, "BGP Prefix Origin Validation", RFC 6811,
	DOI 10.17487/RFC6810, January 2013,		DOI 10.17487/RFC6811, January 2013,
	<http://www.rfc-editor.org/info/rfc6810>.		<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		Appendix A. 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 making of this proposal.
	They include Petr Jiran, Yordan Kritski, Christian Seitz, Nick		They include Petr Jiran, Yordan Kritski, Christian Seitz, Nick
	Hilliard, Joel Jaeggli, Christopher Morrow, Thomas Mangin, Will		Hilliard, Joel Jaeggli, Christopher Morrow, Thomas Mangin, Will
	Hargrave, Niels Bakker and David Farmer.		Hargrave, Niels Bakker, David Farmer, Jared Mauch, John Heasley and
			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
	Email: thomas.king@de-cix.net		Email: thomas.king@de-cix.net
	skipping to change at page 6, line 30 ¶		skipping to change at page 8, line 4 ¶
	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, Inc.		NTT Communications
	Theodorus Majofskistraat 100		Theodorus Majofskistraat 100
	Amsterdam 1065 SZ		Amsterdam 1065 SZ
	NL		NL
	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
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