Difference between revisions of "RFC6441"
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| + | 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''' | |
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| − | Abstract | ||
It has been common for network administrators to filter IP traffic | It has been common for network administrators to filter IP traffic | ||
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routed across the public Internet. | routed across the public Internet. | ||
| − | Status of This Memo | + | '''Status of This Memo''' |
This memo documents an Internet Best Current Practice. | This memo documents an Internet Best Current Practice. | ||
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http://www.rfc-editor.org/info/rfc6441. | 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 | ||
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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 | ||
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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. | ||
| + | |||
| + | 3.1. No Longer Filtering Based on Address Registration | ||
| + | |||
| + | 3.2. Continuing to Filter Traffic from Unallocated IPv4 | ||
== Introduction == | == Introduction == | ||
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"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 [[BCP14|BCP 14]], [[RFC2119|RFC 2119]] | document are to be interpreted as described in [[BCP14|BCP 14]], [[RFC2119|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 that 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 | ||
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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. | ||
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Network operators may deploy filters that block traffic destined for | Network operators may deploy filters that block traffic destined for | ||
Martian prefixes. Currently, the Martian prefix table is defined by | Martian prefixes. Currently, the Martian prefix table is defined by | ||
| − | [RFC5735] which reserves each Martian prefix for some specific, | + | [[RFC5735]] which reserves each Martian prefix for some specific, |
special use. If the Martian prefix table ever changes, that change | special use. If the Martian prefix table ever changes, that change | ||
will be documented in an RFC that either updates or obsoletes | will be documented in an RFC that either updates or obsoletes | ||
| − | [RFC5735]. | + | [[RFC5735]]. |
== Security Considerations == | == Security Considerations == | ||
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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. | ||
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== References == | == References == | ||
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=== Normative References === | === Normative References === | ||
| − | [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate | + | [[RFC2119]] Bradner, S., "Key words for use in RFCs to Indicate |
| − | + | Requirement Levels", [[BCP14|BCP 14]], [[RFC2119|RFC 2119]], March 1997. | |
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| − | [ | + | [[RFC5735]] Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses", |
| − | + | [[BCP153|BCP 153]], [[RFC5735|RFC 5735]], January 2010. | |
| + | === Informative References === | ||
| + | [[RFC1208]] Jacobsen, O. and D. Lynch, "Glossary of networking terms", | ||
| + | [[RFC1208|RFC 1208]], March 1991. | ||
| + | [[RFC3871]] Jones, G., "Operational Security Requirements for Large | ||
| + | Internet Service Provider (ISP) IP Network | ||
| + | Infrastructure", [[RFC3871|RFC 3871]], September 2004. | ||
| + | Appendix A. Acknowledgments | ||
| + | Thanks are owed to Kim Davies, Terry Manderson, Dave Piscitello, and | ||
| + | Joe Abley for helpful advice on how to focus this document. Thanks | ||
| + | also go to Andy Davidson, Philip Smith, and Rob Thomas for early | ||
| + | reviews and suggestions for improvements to the text, and to Carlos | ||
| + | Pignataro for his support and comments. | ||
| + | Author's Address | ||
| + | Leo Vegoda | ||
| + | Internet Corporation for Assigned Names and Numbers | ||
| + | 4676 Admiralty Way, Suite 330 | ||
| + | Marina del Rey, CA 90292 | ||
| + | United States of America | ||
| + | Phone: +1-310-823-9358 | ||
| + | EMail: [email protected] | ||
| + | URI: http://www.iana.org/ | ||
| − | + | [[Category:Best Current Practice]] | |
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Latest revision as of 11:55, 1 October 2020
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
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.
3.1. No Longer Filtering Based on Address Registration
3.2. Continuing to Filter Traffic from Unallocated IPv4
Contents
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.
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
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.
Traffic Filtering Options
No Longer Filtering Based on Address Registration Status
Network administrators who implemented filters for unallocated IPv4 /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 of bogon filters to implement. Now that there are no longer any unallocated unicast IPv4 /8s, there will be legitimate Internet traffic coming from all unicast /8s that are not reserved for special purposes in an RFC.
Removing packet and prefix filters based on the registration status of the IPv4 address is a simple approach that will avoid blocking legitimate Internet traffic. Network operators SHOULD remove both ingress and egress packet filters as well as BGP prefix filters for previously unallocated IPv4 /8s.
Continuing to Filter Traffic from Unallocated IPv4 Space
Some network administrators might want to continue filtering unallocated IPv4 addresses managed by the RIRs. This requires significantly more granular ingress filters and the highly dynamic nature of the RIRs' address pools means that filters need to be updated on a daily basis to avoid blocking legitimate incoming traffic.
Prefixes That Should Not be Routed across the Internet
Network operators may deploy filters that block traffic destined for 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.
Security Considerations
The cessation of filters based on unallocated IPv4 /8 allocations is an evolutionary step towards reasonable security filters. While these filters are no longer necessary, and in fact harmful, this does not obviate the need to continue other security solutions. These other solutions are as necessary today as they ever were.
References
Normative References
RFC2119 Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
RFC5735 Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses",
BCP 153, RFC 5735, January 2010.
Informative References
RFC1208 Jacobsen, O. and D. Lynch, "Glossary of networking terms",
RFC 1208, March 1991.
RFC3871 Jones, G., "Operational Security Requirements for Large
Internet Service Provider (ISP) IP Network
Infrastructure", RFC 3871, September 2004.
Appendix A. Acknowledgments
Thanks are owed to Kim Davies, Terry Manderson, Dave Piscitello, and Joe Abley for helpful advice on how to focus this document. Thanks also go to Andy Davidson, Philip Smith, and Rob Thomas for early reviews and suggestions for improvements to the text, and to Carlos Pignataro for his support and comments.
Author's Address
Leo Vegoda Internet Corporation for Assigned Names and Numbers 4676 Admiralty Way, Suite 330 Marina del Rey, CA 90292 United States of America
Phone: +1-310-823-9358 EMail: [email protected] URI: http://www.iana.org/
