idr W. Kumari
Internet-Draft Google
Intended status: Standards Track R. Bush
Expires: June 1, 2012 Internet Initiative Japan
H. Schiller
Verizon
November 29, 2011
Codification of AS 0 processing.
draft-ietf-idr-as0-00
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
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 1, 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements notation . . . . . . . . . . . . . . . . . . . 3
2. Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 3
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.1. Normative References . . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . . 4
Appendix A. Changes / Author Notes. . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 5
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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
This document specifies that a BGP speaker MUST NOT originate or
propagate a route with an AS number of zero. If a BGP speaker
receives a route which has an AS number of zero in the AS_PATH (or
AS4_PATH) attribute, it SHOULD be logged and treated as a WITHDRAW.
This same behavior applies to routes containing zero as the
Aggregator or AS4 Aggregator.
In addition 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). Obviously enough, 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.
4. Security Considerations
By allowing resource holders to say that AS 0 is the only valid
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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, Robert Raszuk, Danny McPherson,
Keyur Patel, John Scudder. Apologies to those we may have missed, it
was not intentional.
6. References
6.1. Normative References
[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, 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
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.
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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...
Authors' Addresses
Warren Kumari
Google
1600 Amphitheatre Parkway
Mountain View, CA 94043
US
Email: warren@kumari.net
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
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