Internet Engineering Task Force (IETF)                           R. Bush
Request for Comments: 8481                     Internet Initiative Japan
Updates: 6811                                             September 2018
Category: Standards Track
ISSN: 2070-1721


           Clarifications to BGP Origin Validation Based on
              Resource Public Key Infrastructure (RPKI)

Abstract

  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.

Status of This Memo

  This is an Internet Standards Track document.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  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.

  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  https://www.rfc-editor.org/info/rfc8481.

















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Copyright Notice

  Copyright (c) 2018 IETF Trust and the persons identified as the
  document authors.  All rights reserved.

  This document is subject to BCP 78 and the IETF Trust's Legal
  Provisions Relating to IETF Documents
  (https://trustee.ietf.org/license-info) in effect on the date of
  publication of this document.  Please review these documents
  carefully, as they describe your rights and restrictions with respect
  to this document.  Code Components extracted from this document must
  include Simplified BSD License text as described in Section 4.e of
  the Trust Legal Provisions and are provided without warranty as
  described in the Simplified BSD License.

Table of Contents

  1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
  2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
  3.  Suggested Reading . . . . . . . . . . . . . . . . . . . . . .   3
  4.  Evaluate ALL Prefixes . . . . . . . . . . . . . . . . . . . .   3
  5.  Set State, Don't Act  . . . . . . . . . . . . . . . . . . . .   4
  6.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
  7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
  8.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   5
  Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

  Deployment of RPKI-based BGP origin validation 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.

  When a route is distributed into BGP, the origin validation state is
  set to NotFound, Valid, or Invalid per [RFC6811].  Operational
  testing has shown that the specifications of that RFC were not
  sufficient to avoid divergent implementations.  This document
  attempts to clarify two areas which seem to cause confusion.

  The implementation issues seem not to be about how to validate, i.e.,
  how to decide if a route is NotFound, Valid, or Invalid.  The issues
  seem to be which routes should be evaluated and have their evaluation
  state set, and whether to apply policy without operator
  configuration.




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2.  Requirements Language

  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 [RFC2119] [RFC8174] when, and only when, they appear in all
  capitals, as shown here.

3.  Suggested Reading

  It is assumed that the reader understands BGP [RFC4271], the RPKI
  [RFC6480], Route Origin Authorizations (ROAs) [RFC6482], and
  RPKI-based Prefix Validation [RFC6811].

4.  Evaluate ALL Prefixes

  Significant Clarification: A router MUST evaluate and set the
  validation state of all routes in BGP coming from any source (e.g.,
  eBGP, iBGP, or redistribution from static or connected routes),
  unless specifically configured otherwise by the operator.  Otherwise,
  the operator does not have the ability to drop Invalid routes coming
  from every potential source and is therefore liable to complaints
  from neighbors about propagation of Invalid routes.  For this reason,
  [RFC6811] says:

     When a BGP speaker receives an UPDATE from a neighbor, it SHOULD
     perform a lookup as described above for each of the Routes in the
     UPDATE message.  The lookup SHOULD also be applied to routes that
     are redistributed into BGP from another source, such as another
     protocol or a locally defined static route.

  [RFC6811] goes on to say, "An implementation MAY provide
  configuration options to control which routes the lookup is applied
  to."

  When redistributing into BGP from any source (e.g., IGP, iBGP, or
  from static or connected routes), there is no AS_PATH in the input to
  allow RPKI validation of the originating Autonomous System (AS).  In
  such cases, the router MUST use the AS of the router's BGP
  configuration.  If that is ambiguous because of confederation, AS
  migration, or other multi-AS configuration, then the router
  configuration MUST provide a means of specifying the AS to be used on
  the redistribution, either per redistribution or globally.








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5.  Set State, Don't Act

  Significant Clarification: Once routes are evaluated and have their
  state set, the operator should be in complete control of any policy
  applied based on the evaluation state.  Absent specific operator
  configuration, policy MUST NOT be applied.

  Automatic origin validation policy actions such as those described in
  "BGP Prefix Origin Validation State Extended Community" [RFC8097]
  MUST NOT be carried out or otherwise applied unless specifically
  configured by the operator.

6.  Security Considerations

  This document does not create security considerations beyond those of
  [RFC6811].

7.  IANA Considerations

  This document has no IANA actions.

8.  Normative References

  [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119,
             DOI 10.17487/RFC2119, March 1997,
             <https://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,
             <https://www.rfc-editor.org/info/rfc4271>.

  [RFC6480]  Lepinski, M. and S. Kent, "An Infrastructure to Support
             Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
             February 2012, <https://www.rfc-editor.org/info/rfc6480>.

  [RFC6482]  Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
             Origin Authorizations (ROAs)", RFC 6482,
             DOI 10.17487/RFC6482, February 2012,
             <https://www.rfc-editor.org/info/rfc6482>.

  [RFC6811]  Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
             Austein, "BGP Prefix Origin Validation", RFC 6811,
             DOI 10.17487/RFC6811, January 2013,
             <https://www.rfc-editor.org/info/rfc6811>.





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  [RFC8097]  Mohapatra, P., Patel, K., Scudder, J., Ward, D., and R.
             Bush, "BGP Prefix Origin Validation State Extended
             Community", RFC 8097, DOI 10.17487/RFC8097, March 2017,
             <https://www.rfc-editor.org/info/rfc8097>.

  [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
             2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
             May 2017, <https://www.rfc-editor.org/info/rfc8174>.

Acknowledgments

  Many thanks to John Scudder, who had the patience to give
  constructive review multiple times, and Keyur Patel, who noted that
  the AS might have to be specified.  George Michaelson, Jay
  Borkenhagen, John Heasley, and Matthias Waehlisch kindly helped clean
  up loose wording.

Author's Address

  Randy Bush
  Internet Initiative Japan
  5147 Crystal Springs
  Bainbridge Island, Washington  98110
  United States of America

  Email: [email protected]

























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