idr W. Kumari
Internet-Draft Google
Intended status: Standards Track R. Bush
Expires: April 25, 2012 Internet Initiative Japan
H. Schiller
Verizon
October 23, 2011
Codification of AS 0 processing.
draft-wkumari-idr-as0-01
Abstract
This document proscribes the use of AS 0 in BGP OPEN and AS-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
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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 April 25, 2012.
Copyright Notice
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document authors. All rights reserved.
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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
propapate an announcement with an AS number of zero, and a BGP
listener MUST NOT accept an announcement which has an AS number of
zero in the AS-PATH attribute, and SHOULD log the fact that it has
done so.
In addition if a BGP listener recives 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). Obviosuly enough, a router MUST NOT
initialte 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 refernce this document.
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
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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 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 the BGPsec design team, and especially
Randy Bush for providing most of the text.
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 ]
From -00 to -01.
o Forgot to change Informational to Std.
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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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