Default EBGP Route Propagation Behavior Without Policies
draft-ietf-grow-bgp-reject-03

Abstract

This document defines the default behavior of a BGP speaker when there is no import or export policy associated with an External BGP session.

Requirements Language

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 RFC 2119 [RFC2119].

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/.

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This Internet-Draft will expire on August 25, 2017.

Copyright Notice

Copyright (c) 2017 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 2. Solution Requirements
• 3. Acknowledgments
• 4. Security Considerations
• 5. IANA Considerations
• 6. Contributors
• 7. References
• 7.1. Normative References
• 7.2. Informative References
• Authors' Addresses

1. Introduction

BGP [RFC4271] speakers have many default settings which need to be revisited as part of improving the routing ecosystem. There is a need to provide guidance to BGP implementers for the default behaviors of a well functioning Internet ecosystem. Routing leaks [RFC7908] are part of the problem, but software defects and operator misconfigurations are just a few of the attacks on Internet stability we aim to address.

Many deployed BGP speakers send and accept any and all route announcements between their BGP neighbors by default. This practice dates back to the early days of the Internet, where operators were permissive in sending routing information to allow all networks to reach each other. As the Internet has become more densely interconnected, the risk of a misbehaving BGP speaker poses significant risks to Internet routing.

This specification intends to improve this situation by requiring the explicit configuration of a BGP import and export policy for any External BGP (EBGP) session such as customers, peers, or confederation boundaries in a base router or VPN instances. When this solution is implemented, BGP speakers do not accept or send routes without policies configured on EBGP sessions.

2. Solution Requirements

The following requirements apply to the solution described in this document:

• Software MUST consider any routes ineligible for route selection (section 9.1.1 [RFC4271]), if no import policy was configured for the EBGP peer.
• Software MUST NOT advertise any routes to an EBGP peer, if no export policy was configured.
• Software SHOULD fall back to an "import nothing" and "export nothing" mode following failure of internal components, such as a policy engine.
• Software MUST operate in this mode by default.
• Software MAY provide a configuration option to disable this security capability.

3. Acknowledgments

The authors would like to thank the following people for their comments, support and review: Shane Amante, Christopher Morrow, Robert Raszuk, Greg Skinner, Adam Chappell, Sriram Kotikalapudi, Brian Dickson, Jeffrey Haas, and John Heasley.

4. Security Considerations

This document addresses a basic routing security flaw caused by permissive default routing policy configurations. Operators need implementers to address this problem with more secure defaults to mitigate collateral damage on Internet routing. Inadvertent or adversarial advertisements cause business impact that can be mitigated by a secure default behavior.

5. IANA Considerations

This document has no actions for IANA.

6. Contributors

The following people contributed to successful deployment of solution described in this document:

Jakob Heitz
Cisco

Email: jheitz@cisco.com

Ondrej Filip
CZ.NIC

Email: ondrej.filip@nic.cz

7. References

7.1. Normative References

7.2. Informative References

Authors' Addresses