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
 End of changes. 34 change blocks. 
71 lines changed or deleted 133 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/