idr W. Kumari Internet-Draft Google Intended status: Standards Track R. Bush Expires: June 18, 2012 Internet Initiative Japan H. Schiller Verizon December 16, 2011 Codification of AS 0 processing. draft-ietf-idr-as0-01 Abstract This document proscribes the use of AS 0 in BGP OPEN and AS_PATH / AS4_PATH BGP attribute. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any 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 June 18, 2012. Copyright Notice Copyright (c) 2011 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. Kumari, et al. Expires June 18, 2012 [Page 1] Internet-Draft as0-processing December 2011 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements notation . . . . . . . . . . . . . . . . . . . 3 2. Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . . 4 Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5 Kumari, et al. Expires June 18, 2012 [Page 2] Internet-Draft as0-processing December 2011 1. Introduction Autonomous System 0 is listed in the IANA Autonomous System Number Registry as "Reserved - May be use to identify non-routed networks" ([IANA.AS_Numbers]). [I-D.ietf-sidr-iana-objects] specifies that AS number zero in a ROA is used to mark an NLRI which is to be marked as Invalid. No clear statement that AS 0 was proscribed could be found in any BGP specification. As at least two implementations discard routes containing AS 0 (and to allow approaches such as the above) this document codifies this behavior. 1.1. Requirements notation 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. An UPDATE message that contains the AS number of zero in the AS_PATH, AS4_PATH, AGGREGATOR or AS4_AGGREGATOR attribute MUST be considered as malformed, and be handled by the procedures specified in [I-D.ietf-idr-error-handling]. 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] Section 6.2). A router MUST NOT initiate a connection claiming to be AS number zero. 3. IANA Considerations The IANA is requested to update the Reference for number 0 in the "Autonomous System (AS) Numbers" registry to reference this document. Kumari, et al. Expires June 18, 2012 [Page 3] Internet-Draft as0-processing December 2011 4. Security Considerations By allowing resource holders to say 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, and security gotchas often lurk in the undefined spaces. 5. Acknowledgements The authors wish to thank Enke Chen, Brian Dickson, Bruno Decraene, Robert Raszuk, Jakob Heitz, Danny McPherson, Chris Morrow, iLya, Keyur Patel, John Scudder, Jeff Tantsura, Daniel Ginsburg and Susan Hares. Apologies to those we may have missed, it was not intentional. 6. References 6.1. 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-00 (work in progress), November 2011. [IANA.AS_Numbers] IANA, "Autonomous System (AS) Numbers", . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. 6.2. Informative References [I-D.ietf-sidr-iana-objects] Manderson, T., Vegoda, L., and S. Kent, "RPKI Objects Kumari, et al. Expires June 18, 2012 [Page 4] Internet-Draft as0-processing December 2011 issued by IANA", draft-ietf-sidr-iana-objects-03 (work in progress), May 2011. 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" -- Enke Chen o Consistent use of AS_PATH (v., AS-PATH and AS PATH) -- Danny McPherson o New text for Sec 2 P1 -- Enke / Keyur / 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 one and overwrote them by saving on the other, then checked the broken one into SVN. Apologies to all whose comments I may have missed... 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. Authors' Addresses Warren Kumari Google 1600 Amphitheatre Parkway Mountain View, CA 94043 US Email: warren@kumari.net Kumari, et al. Expires June 18, 2012 [Page 5] Internet-Draft as0-processing December 2011 Randy Bush Internet Initiative Japan 5147 Crystal Springs Bainbridge Island, WA 98110 US Email: randy@psg.com Heather Schiller Verizon 22001 Loudoun County Parkway Ashburn 20147 US Email: heather.schiller@verizon.com Kumari, et al. Expires June 18, 2012 [Page 6]