Resource Public Key Infrastructure (RPKI) Origin Validation for BGP ExportInternet Initiative Japan & Arrcus5147 Crystal SpringsBainbridge IslandWA98110United States of Americarandy@psg.comietf@rewvolk.deCisco170 West Tasman DriveSan JoseCA95134United States of Americajheitz@cisco.comroutingsecurityRPKIA BGP speaker may perform Resource Public Key Infrastructure (RPKI)
origin validation not only on
routes received from BGP neighbors and routes that are redistributed
from other routing protocols, but also on routes it sends to BGP
neighbors. For egress policy, it is important that the
classification use the 'effective origin AS' of the processed
route, which may specifically be altered by the commonly available
knobs, such as removing private ASes, confederation handling, and
other modifications of the origin AS. This document updates RFC 6811.Status of This Memo
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received public review and has been approved for publication by
the Internet Engineering Steering Group (IESG). Further
information on Internet Standards is available in Section 2 of
RFC 7841.
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errata, and how to provide feedback on it may be obtained at
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Table of Contents
. Introduction
. Suggested Reading
. Egress Processing
. Operational Considerations
. Security Considerations
. IANA Considerations
. References
. Normative References
. Informative References
Acknowledgments
Authors' Addresses
IntroductionThis document does not change the protocol or semantics of , BGP prefix origin validation. It highlights an
important use case of origin validation in external BGP (eBGP) egress policies,
explaining specifics of correct implementation in this context.The term 'effective origin AS' as used in this document refers to
the Route Origin Autonomous System Number (ASN) of the UPDATE to be
sent to neighboring BGP speakers.The effective origin AS of a BGP UPDATE is decided by
configuration and outbound policy of the BGP speaker. A validating
BGP speaker MUST apply Route Origin Validation policy semantics (see
and )
after applying any egress configuration and policy.This effective origin AS of the announcement might be affected by
removal of private ASes, confederation ,
migration , etc. Any AS_PATH modifications
resulting in effective origin AS change MUST be taken into
account.This document updates by clarifying that
implementations must use the effective origin AS to determine the
Origin Validation state when applying egress policy.
The key words "MUST", "MUST NOT",
"REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "NOT RECOMMENDED",
"MAY", and "OPTIONAL" in this document are
to be interpreted as
described in BCP 14
when, and only when, they appear in all capitals, as shown here.
Suggested ReadingIt is assumed that the reader understands BGP , the RPKI ,
Route Origin Authorizations (ROAs) , RPKI-based Prefix Validation , and Origin Validation
Clarifications .Egress ProcessingBGP implementations supporting RPKI-based origin validation MUST
provide the same policy configuration primitives for decisions based
on the validation state available for use in ingress, redistribution,
and egress policies. When applied to egress policy, validation
state MUST be determined using the effective origin AS of
the route
as it will (or would) be announced to the peer. The effective
origin AS may differ from that of the route in the RIB due to
commonly available knobs, such as removal of private ASes, AS path
manipulation, confederation handling, etc.Egress policy handling can provide more robust protection for
outbound eBGP than relying solely on ingress (iBGP, eBGP, connected,
static, etc.) redistribution being configured and working correctly
-- i.e., better support for the robustness principle.Operational ConsiderationsConfigurations may have a complex policy where the effective
origin AS may not be easily determined before the outbound policies
have been run. It SHOULD be possible to specify a selective origin
validation policy to be applied after any existing non-validating
outbound policies.An implementation SHOULD be able to list announcements that were
not sent to a peer, e.g., because they were marked Invalid, as long
as the router still has them in memory.Security ConsiderationsThis document does not create security considerations beyond
those of and . By
facilitating more correct validation, it attempts to improve BGP
reliability.IANA ConsiderationsThis document has no IANA actions.ReferencesNormative ReferencesKey words for use in RFCs to Indicate Requirement LevelsIn many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.A Border Gateway Protocol 4 (BGP-4)This document discusses the Border Gateway Protocol (BGP), which is an inter-Autonomous System routing protocol.The primary function of a BGP speaking system is to exchange network reachability information with other BGP systems. This network reachability information includes information on the list of Autonomous Systems (ASes) that reachability information traverses. This information is sufficient for constructing a graph of AS connectivity for this reachability from which routing loops may be pruned, and, at the AS level, some policy decisions may be enforced.BGP-4 provides a set of mechanisms for supporting Classless Inter-Domain Routing (CIDR). These mechanisms include support for advertising a set of destinations as an IP prefix, and eliminating the concept of network "class" within BGP. BGP-4 also introduces mechanisms that allow aggregation of routes, including aggregation of AS paths.This document obsoletes RFC 1771. [STANDARDS-TRACK]Autonomous System Confederations for BGPThe Border Gateway Protocol (BGP) is an inter-autonomous system routing protocol designed for Transmission Control Protocol/Internet Protocol (TCP/IP) networks. BGP requires that all BGP speakers within a single autonomous system (AS) must be fully meshed. This represents a serious scaling problem that has been well documented in a number of proposals.This document describes an extension to BGP that may be used to create a confederation of autonomous systems that is represented as a single autonomous system to BGP peers external to the confederation, thereby removing the "full mesh" requirement. The intention of this extension is to aid in policy administration and reduce the management complexity of maintaining a large autonomous system.This document obsoletes RFC 3065. [STANDARDS-TRACK]A Profile for Route Origin Authorizations (ROAs)This document defines a standard profile for Route Origin Authorizations (ROAs). A ROA is a digitally signed object that provides a means of verifying that an IP address block holder has authorized an Autonomous System (AS) to originate routes to one or more prefixes within the address block. [STANDARDS-TRACK]BGP Prefix Origin ValidationTo help reduce well-known threats against BGP including prefix mis- announcing and monkey-in-the-middle attacks, one of the security requirements is the ability to validate the origination Autonomous System (AS) of BGP routes. More specifically, one needs to validate that the AS number claiming to originate an address prefix (as derived from the AS_PATH attribute of the BGP route) is in fact authorized by the prefix holder to do so. This document describes a simple validation mechanism to partially satisfy this requirement. [STANDARDS-TRACK]Autonomous System Migration Mechanisms and Their Effects on the BGP AS_PATH AttributeThis document discusses some existing commonly used BGP mechanisms for Autonomous System Number (ASN) migration that are not formally part of the BGP4 protocol specification. It is necessary to document these de facto standards to ensure that they are properly supported in future BGP protocol work.Ambiguity of Uppercase vs Lowercase in RFC 2119 Key WordsRFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.Clarifications to BGP Origin Validation Based on Resource Public Key Infrastructure (RPKI)Deployment of BGP origin validation based on Resource Public Key Infrastructure (RPKI) is hampered by, among other things, vendor misimplementations in two critical areas: which routes are validated and whether policy is applied when not specified by configuration. This document is meant to clarify possible misunderstandings causing those misimplementations; it thus updates RFC 6811 by clarifying that all prefixes should have their validation state set and that policy must not be applied without operator configuration.Informative ReferencesAn Infrastructure to Support Secure Internet RoutingThis document describes an architecture for an infrastructure to support improved security of Internet routing. The foundation of this architecture is a Resource Public Key Infrastructure (RPKI) that represents the allocation hierarchy of IP address space and Autonomous System (AS) numbers; and a distributed repository system for storing and disseminating the data objects that comprise the RPKI, as well as other signed objects necessary for improved routing security. As an initial application of this architecture, the document describes how a legitimate holder of IP address space can explicitly and verifiably authorize one or more ASes to originate routes to that address space. Such verifiable authorizations could be used, for example, to more securely construct BGP route filters. This document is not an Internet Standards Track specification; it is published for informational purposes.AcknowledgmentsThanks to reviews and comments from , ,
, ,
,
, ,
, and .Authors' AddressesInternet Initiative Japan & Arrcus5147 Crystal SpringsBainbridge IslandWA98110United States of Americarandy@psg.comietf@rewvolk.deCisco170 West Tasman DriveSan JoseCA95134United States of Americajheitz@cisco.com