idrInternet Engineering Task Force (IETF) W. KumariInternet-DraftRequest for Comments: 7607 Google Updates: 4271(if approved)R. BushIntended status:Category: Standards Track Internet Initiative JapanExpires: February 27, 2013ISSN: 2070-1721 H. SchillerVerizonGoogle K. Patel Cisco Systems August26, 20122015 Codification of AS 0processing. draft-ietf-idr-as0-06Processing Abstract This document updates RFC 4271 and proscribes the use of Autonomous System (AS) 0 in the Border Gateway Protocol (BGP)OPENOPEN, AS_PATH, AS4_PATH, AGGREGATOR, andAS_PATH / AS4_PATHAS4_AGGREGATOR attributes in the BGPattribute.UPDATE message. Status ofthisThis Memo ThisInternet-Draftissubmitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documentsan Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF).Note that other groups may also distribute working documents as Internet-Drafts. The listIt represents the consensus ofcurrent Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents validthe IETF community. It has received public review and has been approved fora maximumpublication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 ofsix monthsRFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may beupdated, replaced, or obsoleted by other documentsobtained atany time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on February 27, 2013.http://www.rfc-editor.org/info/rfc7607. Copyright Notice Copyright (c)20122015 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 (http://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 . . . . . . . . . . . . . . . . . . . . . . . .. 32 1.1. Requirementsnotation .Notation . . . . . . . . . . . . . . . . . .32 2. Behavior . . . . . . . . . . . . . . . . . . . . . . . . . ..3 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . .. 43 4. Security Considerations . . . . . . . . . . . . . . . . . . .. 43 5.Acknowledgements . . . . . .References . . . . . . . . . . . . . . . . .4 6. References. . . . . . . . 4 5.1. Normative References . . . . . . . . . . . . . . . . . . 46.1. Normative5.2. Informative References . . . . . . . . . . . . . . . . .. .46.2. Informative References . . . . . . . .Acknowledgements . . . . . . . . . .5 Appendix A. Changes / Author Notes.. . . . . . . . . . . . . .. 54 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . .. 65 1. Introduction Autonomous System 0iswas listed in the IANA Autonomous System Number Registry as "Reserved - May be use [sic] to identify non-routed networks" ([IANA.AS_Numbers]). [RFC6491] specifies that ASnumber zero0 in a Route Origin Attestation (ROA) is used to mark a prefix and all its more specific prefixes as not to be used in a routing context. This allows a resource holder to signal that a prefix (and the more specifics) should not be routed by publishing a ROA listingAS0AS 0 as the only origin. To respond to this signalrequresrequires that BGP implementationsdonot accept or propagate routes containingAS0.AS 0. No clear statement that AS 0 was proscribed could be found in any BGP specification. This document corrects this omission, most importantly in the case of the AS_PATH. This represents an update to the error handling procedures given in[RFC4271]Sections 6.2 and 6.3 of [RFC4271] by specifying the behavior in the presence ofAS0.AS 0. At least two implementations discard routes containing AS 0, and this document codifies this behavior. 1.1. RequirementsnotationNotation The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Behavior A BGP speaker MUST NOT originate or propagate a route with an AS number of zero in the AS_PATH, AS4_PATH,AGGREGATORAGGREGATOR, or AS4_AGGREGATOR attributes. An UPDATE message that contains the AS number of zero in the AS_PATH or AGGREGATOR attribute MUST be considered asmalformed,malformed and be handled by the procedures specified in[I-D.ietf-idr-error-handling].[RFC7606]. An UPDATE message that contains the AS number of zero in the AS4_PATH or AS4_AGGREGATOR attribute MUST be considered asmalformed,malformed and be handled by the procedures specified in[I-D.ietf-idr-rfc4893bis].[RFC6793]. If a BGP speaker receives zero as the peer AS in an OPEN message, it MUST abort the connection and send a NOTIFICATION with Error Code "OPEN Message Error" and subcode "Bad Peer AS" (see[RFC4271]Section6.2).6 of [RFC4271]). A router MUST NOT initiate a connection claiming to be ASnumber zero.0. Authors of future protocol extensions that carry the Autonomous System number are encouraged to keep in mind that ASnumber zero0 is reserved and to provide clear direction on how to handle ASnumber zero.0. 3. IANA Considerations The IANAis requested to updatehas updated theReferenceregistry fornumber 0 in the "Autonomous"16-bit Autonomous System(AS)Numbers"registry to reference this document.so that the entry for AS 0 is simply "Reserved". 4. Security Considerations By allowing a Resource Public Key Infrastructure (RPKI) resource holder to issue a ROA saying that AS 0 is the only valid origin for a route, we allow them to state that a particular address resource is not in use. By ensuring that all implementations that see AS 0 in a route ignore that route, we prevent a malicious party from announcing routes containing AS 0 in an attempt to hijack those resources. In addition, by standardizing the behavior upon reception of an AS_PATH (or AS4_PATH) containing AS 0, this document makes the behavior better defined. 5.Acknowledgements The authors wish to thank Elwyn Davies, Enke Chen, Brian Dickson, Bruno Decraene, Robert Raszuk, Jakob Heitz, Danny McPherson, Chris Morrow, iLya, John Scudder, Jeff Tantsura, Daniel Ginsburg and Susan Hares. Apologies to those we may have missed, it was not intentional. 6.References6.1.5.1. Normative References[I-D.ietf-idr-error-handling] Scudder, J., Chen, E., Mohapatra, P., and K. Patel, "Revised Error Handling for BGP UPDATE Messages", draft-ietf-idr-error-handling-01 (work in progress), December 2011. [I-D.ietf-idr-rfc4893bis] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS Number Space", draft-ietf-idr-rfc4893bis-06 (work in progress), April 2012.[IANA.AS_Numbers] IANA, "Autonomous System (AS) Numbers", <http://www.iana.org/assignments/as-numbers>. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ RFC2119, March1997.1997, <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, January2006. 6.2.2006, <http://www.rfc-editor.org/info/rfc4271>. [RFC6793] Vohra, Q. and E. Chen, "BGP Support for Four-Octet Autonomous System (AS) Number Space", RFC 6793, DOI 10.17487/RFC6793, December 2012, <http://www.rfc-editor.org/info/rfc6793>. [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, July 2015, <http://www.rfc-editor.org/info/rfc7606>. 5.2. Informative References [RFC6491] Manderson, T., Vegoda, L., and S. Kent, "Resource Public Key Infrastructure (RPKI) Objects Issued by IANA", RFC 6491, DOI 10.17487/RFC6491, February2012. Appendix A. Changes / Author Notes. [RFC Editor: Please remove this section before publication ] Draft accepted as IDR Doc, notes reset. Please see notes for draft-wkumari-idr-as0.xml for prior comments. Changes -00. o Added AS4_PATH -- Robert Raszuk. o Change "bgp listener" to "bgp speaker" --2012, <http://www.rfc-editor.org/info/rfc6491>. Acknowledgements The authors wish to thank Elwyn Davies, EnkeChen o Consistent use of AS_PATH (v., AS-PATH and AS PATH) --Chen, Brian Dickson, Bruno Decraene, Robert Raszuk, Jakob Heitz, DannyMcPherson o New text for Sec 2 P1 -- Enke / Keyur /McPherson, Chris Morrow, iLya, John Scudder,http://www.ietf.org/mail-archive/web/idr/current/msg05786.html o I made a boo boo -- I had the file open in 2 editors, made changes in oneJeff Tantsura, Daniel Ginsburg, andoverwrote them by saving on the "other, then checked the broken one into SVN.Susan Hares. Apologies toall whose comments Ithose we may havemissed... Changes -01 o The WG thread http://www.ietf.org/mail-archive/web/idr/current/msg05685.html showed a very strong preference for separating the error definition and handling -- the chairs also showed a prefernce to Publish this and point to the error handling that Enke will write. o The originally suggested text ("An UPDATE message that contains the AS number of zero in the AS-PATH attribute MUST be...") only referenced the AS-PATH, readded AS4_PATH, *AGGREGATOR as suggested by Robert Raszak and Danny. Changes -02 o Fixed the reference for *AGGREGATOR. This required breakingmissed; itout into two sentences / clauses. o Added text on other places where an AS can show up (e.g: "4-Octet AS specific Extended Community" [5668]) -- thanks to Keyur. Changes - 03 o Removed text on other places where an AS can show up (e.g: "4-Octet AS specific Extended Community" [5668]). o Added *very* generic "Authors of future protocol extensions..." text Changes -04 o Looks like the draft needs an 'Updates: RFC 4271' header. Can you make the change? -- JGS. o "You have things a bit scrambled in these two paragraphs" -- JGS (whoops!). o Editorial: I suggest dropping the parentheses in... JGS. o Added "This document updates rfc 4271" to keep IDNITs happy... o Bumped refs: draft-ietf-sidr-iana-objects has been published as RFC 6491, idr-error is now -01, 4893bis is now -06 Changes - 05 o Added something to the intro saying what we update and why. Thiswasin the abstract, but I didn't have it in the intro. Stupid. Changes - 06 o Incorporated some comments / clarifications from Gen-ART review (Elwyn Davies) o Expaned acronyms. o RFC 6491 fix - clarified what it actually said and what implications are.not intentional. Authors' Addresses Warren Kumari Google 1600 Amphitheatre Parkway Mountain View, CA 94043USUnited States Email: warren@kumari.net Randy Bush Internet Initiative Japan 5147 Crystal Springs Bainbridge Island, WA 98110USUnited States Email: randy@psg.com Heather SchillerVerizon 22001 Loudoun CountyGoogle 1600 Amphitheatre ParkwayAshburn 20147 USMountain View, CA 94043 United States Email:heather.schiller@verizon.comhas@google.com Keyur Patel Cisco Systems 170 W. Tasman Drive San Jose, CA 95134USA Phone: Fax:United States Email: keyupate@cisco.comURI: