draft-ietf-grow-no-more-unallocated-slash8s-04.txt   rfc6441.txt 
Network Working Group L. Vegoda Internet Engineering Task Force (IETF) L. Vegoda
Internet-Draft ICANN Request for Comments: 6441 ICANN
Intended status: BCP October 12, 2011 BCP: 171 November 2011
Expires: April 14, 2012 Category: Best Current Practice
ISSN: 2070-1721
Time to Remove Filters for Previously Unallocated IPv4 /8s Time to Remove Filters for Previously Unallocated IPv4 /8s
draft-ietf-grow-no-more-unallocated-slash8s-04
Abstract Abstract
It has been common for network administrators to filter IP traffic It has been common for network administrators to filter IP traffic
from and BGP prefixes of unallocated IPv4 address space. Now that from and BGP prefixes of unallocated IPv4 address space. Now that
there are no longer any unallocated IPv4 /8s, this practise is more there are no longer any unallocated IPv4 /8s, this practise is more
complicated, fragile and expensive. Network administrators are complicated, fragile, and expensive. Network administrators are
advised to remove filters based on the registration status of the advised to remove filters based on the registration status of the
address space. address space.
This document explains why any remaining packet and BGP prefix This document explains why any remaining packet and BGP prefix
filters for unallocated IPv4 /8s should now be removed on border filters for unallocated IPv4 /8s should now be removed on border
routers and documents those IPv4 unicast prefixes that should not be routers and documents those IPv4 unicast prefixes that should not be
routed across the public Internet. routed across the public Internet.
Status of this Memo 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 This memo documents an Internet Best Current Practice.
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 This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
BCPs is available in Section 2 of RFC 5741.
This Internet-Draft will expire on April 14, 2012. 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 Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Traffic Filtering Options . . . . . . . . . . . . . . . . . . . 3 3. Traffic Filtering Options . . . . . . . . . . . . . . . . . . . 3
3.1. No Longer Filtering Based on Address Registration 3.1. No Longer Filtering Based on Address Registration
Status . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Status . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2. Continuing to Filter Traffic from Unallocated IPv4 3.2. Continuing to Filter Traffic from Unallocated IPv4
Space . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Space . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Prefixes That Should Not be Routed Across the Internet . . . . 4 4. Prefixes That Should Not be Routed across the Internet . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 3
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . . 5 6.2. Informative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . . 5 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 5
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
It has been common for network administrators to filter IP traffic It has been common for network administrators to filter IP traffic
from and BGP prefixes of unallocated IPv4 address space. Now that from and BGP prefixes of unallocated IPv4 address space. Now that
there are no longer any unallocated IPv4 /8s, this practise is more there are no longer any unallocated IPv4 /8s, this practise is more
complicated, fragile and expensive. Network administrators are complicated, fragile, and expensive. Network administrators are
advised to remove filters based on the registration status of the advised to remove filters based on the registration status of the
address space. address space.
This document explains why any remaining packet and BGP prefix This document explains why any remaining packet and BGP prefix
filters for unallocated IPv4 /8s should now be removed on border filters for unallocated IPv4 /8s should now be removed on border
routers and documents those IPv4 unicast prefixes that should not be routers and documents those IPv4 unicast prefixes that should not be
routed across the public Internet. routed across the public Internet.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119 document are to be interpreted as described in BCP 14, RFC 2119
[RFC2119]. [RFC2119].
Martians [RFC1208] is a humorous term applied to packets that turn up Martians [RFC1208] is a humorous term applied to packets that turn up
unexpectedly on the wrong network because of bogus routing entries. unexpectedly on the wrong network because of bogus routing entries.
It is also used as a name for a packet which has an altogether bogus It is also used as a name for a packet that has an altogether bogus
(non-registered or ill-formed) Internet address. Bogons [RFC3871] (non-registered or ill-formed) Internet address. Bogons [RFC3871]
are packets sourced from addresses that have not yet been allocated are packets sourced from addresses that have not yet been allocated
by IANA or the Regional Internet Registries (RIRs), or addresses by IANA or the Regional Internet Registries (RIRs), or addresses
reserved for private or special use by RFCs [RFC5735].Bogons are reserved for private or special use by RFCs [RFC5735]. Bogons are
referred to as "Dark IP" in some circles. . referred to as "Dark IP" in some circles.
3. Traffic Filtering Options 3. Traffic Filtering Options
3.1. No Longer Filtering Based on Address Registration Status 3.1. No Longer Filtering Based on Address Registration Status
Network administrators who implemented filters for unallocated IPv4 Network administrators who implemented filters for unallocated IPv4
/8s did so in the knowledge that those /8s were not a legitimate /8s did so in the knowledge that those /8s were not a legitimate
source of traffic on the Internet and that there was a small number source of traffic on the Internet and that there was a small number
of bogon filters to implement. Now that there are no longer any of bogon filters to implement. Now that there are no longer any
unallocated unicast IPv4 /8s, there will be legitimate Internet unallocated unicast IPv4 /8s, there will be legitimate Internet
skipping to change at page 4, line 15 skipping to change at page 3, line 35
3.2. Continuing to Filter Traffic from Unallocated IPv4 Space 3.2. Continuing to Filter Traffic from Unallocated IPv4 Space
Some network administrators might want to continue filtering Some network administrators might want to continue filtering
unallocated IPv4 addresses managed by the RIRs. This requires unallocated IPv4 addresses managed by the RIRs. This requires
significantly more granular ingress filters and the highly dynamic significantly more granular ingress filters and the highly dynamic
nature of the RIRs' address pools means that filters need to be nature of the RIRs' address pools means that filters need to be
updated on a daily basis to avoid blocking legitimate incoming updated on a daily basis to avoid blocking legitimate incoming
traffic. traffic.
4. Prefixes That Should Not be Routed Across the Internet 4. Prefixes That Should Not be Routed across the Internet
Network operators who only wish to filter traffic originating from
addresses that should never be routed across the Internet, Martians,
can deploy a set of packet and prefix filters designed to block
traffic from address blocks reserved for special purposes. These
are:
- 0.0.0.0/8 (Local identification) [RFC1122];
- 10.0.0.0/8 (Private use) [RFC1918];
- 127.0.0.0/8 (Loopback) [RFC1122];
- 169.254.0.0/16 (Link local) [RFC3927];
- 172.16.0.0/12 (Private use) [RFC1918];
- 192.0.2.0/24 (TEST-NET-1) [RFC5737];
- 192.168.0.0/16 (Private use) [RFC1918];
- 198.18.0.0/15 (Benchmark testing) [RFC2544];
- 198.51.100.0/24 (TEST-NET-2) [RFC5737];
- 203.0.113.0/24 (TEST-NET-3) [RFC5737];
- 224.0.0.0/4 (Multicast) [RFC5771]; and
- 240.0.0.0/4 (Future use) [RFC1112].
A full set of special use IPv4 addresses can be found in [RFC5735]. Network operators may deploy filters that block traffic destined for
It includes prefixes that are intended for Internet use. Martian prefixes. Currently, the Martian prefix table is defined by
[RFC5735] which reserves each Martian prefix for some specific,
special use. If the Martian prefix table ever changes, that change
will be documented in an RFC that either updates or obsoletes
[RFC5735].
5. Security Considerations 5. Security Considerations
The cessation of filters based on unallocated IPv4 /8 allocations is The cessation of filters based on unallocated IPv4 /8 allocations is
an evolutionary step towards reasonable security filters. While an evolutionary step towards reasonable security filters. While
these filters are no longer necessary, and in fact harmful, this does these filters are no longer necessary, and in fact harmful, this does
not obviate the need to continue other security solutions. These not obviate the need to continue other security solutions. These
other solutions are as necessary today as they ever were. other solutions are as necessary today as they ever were.
6. IANA Considerations 6. References
This document makes no request of IANA.
7. References
7.1. Normative References
[RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5,
RFC 1112, August 1989.
[RFC1122] Braden, R., "Requirements for Internet Hosts -
Communication Layers", STD 3, RFC 1122, October 1989.
[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and 6.1. Normative References
E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, February 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic
Configuration of IPv4 Link-Local Addresses", RFC 3927,
May 2005.
[RFC5735] Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses", [RFC5735] Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses",
BCP 153, RFC 5735, January 2010. BCP 153, RFC 5735, January 2010.
[RFC5771] Cotton, M., Vegoda, L., and D. Meyer, "IANA Guidelines for 6.2. Informative References
IPv4 Multicast Address Assignments", BCP 51, RFC 5771,
March 2010.
7.2. Informative References
[RFC1208] Jacobsen, O. and D. Lynch, "Glossary of networking terms", [RFC1208] Jacobsen, O. and D. Lynch, "Glossary of networking terms",
RFC 1208, March 1991. RFC 1208, March 1991.
[RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for
Network Interconnect Devices", RFC 2544, March 1999.
[RFC3871] Jones, G., "Operational Security Requirements for Large [RFC3871] Jones, G., "Operational Security Requirements for Large
Internet Service Provider (ISP) IP Network Internet Service Provider (ISP) IP Network
Infrastructure", RFC 3871, September 2004. Infrastructure", RFC 3871, September 2004.
[RFC5737] Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks
Reserved for Documentation", RFC 5737, January 2010.
Appendix A. Acknowledgments Appendix A. Acknowledgments
Thanks are owed to Kim Davies, Terry Manderson, Dave Piscitello and Thanks are owed to Kim Davies, Terry Manderson, Dave Piscitello, and
Joe Abley for helpful advice on how to focus this document. Thanks Joe Abley for helpful advice on how to focus this document. Thanks
also go to Andy Davidson, Philip Smith and Rob Thomas for early also go to Andy Davidson, Philip Smith, and Rob Thomas for early
reviews and suggestions for improvements to the text and Carlos reviews and suggestions for improvements to the text, and to Carlos
Pignataro for his support and comments. Pignataro for his support and comments.
Author's Address Author's Address
Leo Vegoda Leo Vegoda
Internet Corporation for Assigned Names and Numbers Internet Corporation for Assigned Names and Numbers
4676 Admiralty Way, Suite 330 4676 Admiralty Way, Suite 330
Marina del Rey, CA 90292 Marina del Rey, CA 90292
United States of America United States of America
Phone: +1-310-823-9358 Phone: +1-310-823-9358
Email: leo.vegoda@icann.org EMail: leo.vegoda@icann.org
URI: http://www.iana.org/ URI: http://www.iana.org/
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