Time to Remove Filters for Previously Unallocated IPv4 /8s
RFC 6441
Document | Type |
RFC - Best Current Practice
(November 2011; No errata)
Also known as BCP 171
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Author | Leo Vegoda | ||
Last updated | 2018-12-20 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | WG Document | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6441 (Best Current Practice) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ron Bonica | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) L. Vegoda Request for Comments: 6441 ICANN BCP: 171 November 2011 Category: Best Current Practice ISSN: 2070-1721 Time to Remove Filters for Previously Unallocated IPv4 /8s Abstract It has been common for network administrators to filter IP traffic from and BGP prefixes of unallocated IPv4 address space. Now that there are no longer any unallocated IPv4 /8s, this practise is more complicated, fragile, and expensive. Network administrators are advised to remove filters based on the registration status of the address space. This document explains why any remaining packet and BGP prefix filters for unallocated IPv4 /8s should now be removed on border routers and documents those IPv4 unicast prefixes that should not be routed across the public Internet. Status of This Memo This memo documents an Internet Best Current Practice. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on BCPs is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6441. 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 Vegoda Best Current Practice [Page 1] RFC 6441 Remove /8 Filters November 2011 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 . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Traffic Filtering Options . . . . . . . . . . . . . . . . . . . 3 3.1. No Longer Filtering Based on Address Registration Status . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.2. Continuing to Filter Traffic from Unallocated IPv4 Space . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 4. Prefixes That Should Not be Routed across the Internet . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 3 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4 6.1. Normative References . . . . . . . . . . . . . . . . . . . 4 6.2. Informative References . . . . . . . . . . . . . . . . . . 4 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 5 1. Introduction It has been common for network administrators to filter IP traffic from and BGP prefixes of unallocated IPv4 address space. Now that there are no longer any unallocated IPv4 /8s, this practise is more complicated, fragile, and expensive. Network administrators are advised to remove filters based on the registration status of the address space. This document explains why any remaining packet and BGP prefix filters for unallocated IPv4 /8s should now be removed on border routers and documents those IPv4 unicast prefixes that should not be routed across the public Internet. 2. Terminology 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 BCP 14, RFC 2119 [RFC2119]. Martians [RFC1208] is a humorous term applied to packets that turn up unexpectedly on the wrong network because of bogus routing entries. It is also used as a name for a packet that has an altogether bogus (non-registered or ill-formed) Internet address. Bogons [RFC3871] are packets sourced from addresses that have not yet been allocated Vegoda Best Current Practice [Page 2] RFC 6441 Remove /8 Filters November 2011 by IANA or the Regional Internet Registries (RIRs), or addresses reserved for private or special use by RFCs [RFC5735]. Bogons are referred to as "Dark IP" in some circles. 3. Traffic Filtering Options 3.1. No Longer Filtering Based on Address Registration Status Network administrators who implemented filters for unallocated IPv4Show full document text