[Note that this file is a concatenation of more than one RFC.] Internet Engineering Task Force (IETF) J. Weil Request for Comments: 6598 Time Warner Cable BCP: 153 V. Kuarsingh Updates: 5735 Rogers Communications Category: Best Current Practice C. Donley ISSN: 2070-1721 CableLabs C. Liljenstolpe Telstra Corp. M. Azinger Frontier Communications April 2012 IANA-Reserved IPv4 Prefix for Shared Address Space Abstract This document requests the allocation of an IPv4 /10 address block to be used as Shared Address Space to accommodate the needs of Carrier- Grade NAT (CGN) devices. It is anticipated that Service Providers will use this Shared Address Space to number the interfaces that connect CGN devices to Customer Premises Equipment (CPE). Shared Address Space is distinct from RFC 1918 private address space because it is intended for use on Service Provider networks. However, it may be used in a manner similar to RFC 1918 private address space on routing equipment that is able to do address translation across router interfaces when the addresses are identical on two different interfaces. Details are provided in the text of this document. This document details the allocation of an additional special-use IPv4 address block and updates RFC 5735. 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/rfc6598. Weil, et al. Best Current Practice [Page 1] RFC 6598 Shared Address Space Request April 2012 IESG Note A number of operators have expressed a need for the special-purpose IPv4 address allocation described by this document. During deliberations, the IETF community demonstrated very rough consensus in favor of the allocation. While operational expedients, including the special-purpose address allocation described in this document, may help solve a short-term operational problem, the IESG and the IETF remain committed to the deployment of IPv6. Copyright Notice Copyright (c) 2012 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. Table of Contents 1. Introduction ....................................................3 2. Requirements Language ...........................................3 3. Alternatives to Shared Address Space ............................3 4. Use of Shared CGN Space .........................................4 5. Risk ............................................................5 5.1. Analysis ...................................................5 5.2. Empirical Data .............................................6 6. Security Considerations .........................................7 7. IANA Considerations .............................................8 8. References ......................................................8 8.1. Normative References .......................................8 8.2. Informative References .....................................9 Appendix A. Acknowledgments .......................................10 Weil, et al. Best Current Practice [Page 2] RFC 6598 Shared Address Space Request April 2012 1. Introduction IPv4 address space is nearly exhausted. However, ISPs must continue to support IPv4 growth until IPv6 is fully deployed. To that end, many ISPs will deploy a Carrier-Grade NAT (CGN) device, such as that described in [RFC6264]. Because CGNs are used on networks where public address space is expected, and currently available private address space causes operational issues when used in this context, ISPs require a new IPv4 /10 address block. This address block will be called the "Shared Address Space" and will be used to number the interfaces that connect CGN devices to Customer Premises Equipment (CPE). Shared Address Space is similar to [RFC1918] private address space in that it is not globally routable address space and can be used by multiple pieces of equipment. However, Shared Address Space has limitations in its use that the current [RFC1918] private address space does not have. In particular, Shared Address Space can only be used in Service Provider networks or on routing equipment that is able to do address translation across router interfaces when the addresses are identical on two different interfaces. This document requests the allocation of an IPv4 /10 address block to be used as Shared Address Space. In conversations with many ISPs, a /10 is the smallest block that will allow them to deploy CGNs on a regional basis without requiring nested CGNs. For instance, as described in [ISP-SHARED-ADDR], a /10 is sufficient to service Points of Presence in the Tokyo area. This document details the allocation of an additional special-use IPv4 address block and updates [RFC5735]. 2. 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]. 3. Alternatives to Shared Address Space The interfaces that connect CGN devices to CPE might conceivably be numbered from any of the following address spaces: o legitimately assigned globally unique address space o usurped globally unique address space (i.e., squat space) Weil, et al. Best Current Practice [Page 3] RFC 6598 Shared Address Space Request April 2012 o [RFC1918] space o Shared Address Space A Service Provider can number the interfaces in question from legitimately assigned globally unique address space. While this solution poses the fewest problems, it is impractical because globally unique IPv4 address space is in short supply. While the Regional Internet Registries (RIRs) have enough address space to allocate a single /10 to be shared by all Service Providers, they do not have enough address space to make a unique assignment to each Service Provider. Service Providers MUST NOT number the interfaces in question from usurped globally unique address space (i.e., squat space). If a Service Provider leaks advertisements for squat space into the global Internet, the legitimate holders of that address space may be adversely impacted, as would those wishing to communicate with them. Even if the Service Provider did not leak advertisements for squat space, the Service Provider and its subscribers might lose connectivity to the legitimate holders of that address space. A Service Provider can number the interfaces in question from [RFC1918] space if at least one of the following conditions is true: o The Service Provider knows that the CPE/NAT works correctly when the same [RFC1918] address block is used on both its inside and outside interfaces. o The Service Provider knows that the [RFC1918] address block that it uses to number interfaces between the CGN and CPE is not used on the subscriber side of the CPE. Unless at least one of the conditions above is true, the Service Provider cannot safely use [RFC1918] address space and must resort to Shared Address Space. This is typically the case in an unmanaged service, where subscribers provide their own CPE and number their own internal network. 4. Use of Shared CGN Space Shared Address Space is IPv4 address space designated for Service Provider use with the purpose of facilitating CGN deployment. Also, Shared Address Space can be used as additional non-globally routable space on routing equipment that is able to do address translation across router interfaces when the addresses are identical on two different interfaces. Weil, et al. Best Current Practice [Page 4] RFC 6598 Shared Address Space Request April 2012 Devices MUST be capable of performing address translation when identical Shared Address Space ranges are used on two different interfaces. Packets with Shared Address Space source or destination addresses MUST NOT be forwarded across Service Provider boundaries. Service Providers MUST filter such packets on ingress links. One exception to this paragraph's proscription is in the case of business relationships, such as hosted CGN services. When running a single DNS infrastructure, Service Providers MUST NOT include Shared Address Space in zone files. When running a split DNS infrastructure, Service Providers MUST NOT include Shared Address Space in external-facing zone files. Reverse DNS queries for Shared Address Space addresses MUST NOT be forwarded to the global DNS infrastructure. DNS Providers SHOULD filter requests for Shared Address Space reverse DNS queries on recursive nameservers. This is done to avoid having to set up something similar to AS112.net for [RFC1918] private address space that a host has incorrectly sent for a DNS that reverse-maps queries on the public Internet [RFC6304]. Because CGN service requires non-overlapping address space on each side of the home NAT and CGN, entities using Shared Address Space for purposes other than for CGN service, as described in this document, are likely to experience problems implementing or connecting to CGN service at such time as they exhaust their supply of public IPv4 addresses. 5. Risk 5.1. Analysis Some existing applications discover the outside address of their local CPE, determine whether the address is reserved for special use, and behave differently based on that determination. If a new IPv4 address block is reserved for special use and that block is used to number CPE outside interfaces, some of the above-mentioned applications may fail. For example, assume that an application requires its peer (or some other device) to initiate an incoming connection directly with its CPE's outside address. That application discovers the outside address of its CPE and determines whether that address is reserved for special use. If the address is reserved for special use, the application rightly concludes that the address is not reachable from Weil, et al. Best Current Practice [Page 5] RFC 6598 Shared Address Space Request April 2012 the global Internet and behaves in one manner. If the address is not reserved for special use, the application assumes that the address is reachable from the global Internet and behaves in another manner. While the assumption that a non-special-use address is reachable from the global Internet is generally safe, it is not always true (e.g., when the CPE outside interface is numbered from globally unique address space but that address is not advertised to the global Internet as when it is behind a CGN). Such an assumption could cause certain applications to behave incorrectly in those cases. 5.2. Empirical Data The primary motivation for the allocation of Shared Address Space is as address space for CGNs; the use and impact of CGNs has been previously described in [RFC6269] and [NAT444-IMPACTS]. Some of the services adversely impacted by CGNs are as follows: 1. Console gaming -- some games fail when two subscribers using the same outside public IPv4 address try to connect to each other. 2. Video streaming -- performance is impacted when using one of several popular video-streaming technologies to deliver multiple video streams to users behind particular CPE routers. 3. Peer-to-peer -- some peer-to-peer applications cannot seed content due to the inability to open incoming ports through the CGN. Likewise, some SIP client implementations cannot receive incoming calls unless they first initiate outgoing traffic or open an incoming port through the CGN using the Port Control Protocol (PCP) [PCP-BASE] or a similar mechanism. 4. Geo-location -- geo-location systems identify the location of the CGN server, not the end host. 5. Simultaneous logins -- some websites (particularly banking and social-networking websites) restrict the number of simultaneous logins per outside public IPv4 address. 6. 6to4 -- 6to4 requires globally reachable addresses and will not work in networks that employ addresses with limited topological span, such as those employing CGNs. Based on testing documented in [NAT444-IMPACTS], the CGN impacts on items 1-5 above are comparable regardless of whether globally unique, Shared Address Space, or [RFC1918] addresses are used. There is, however, a difference between the three alternatives in the treatment of 6to4. Weil, et al. Best Current Practice [Page 6] RFC 6598 Shared Address Space Request April 2012 As described in [RFC6343], CPE routers do not attempt to initialize 6to4 tunnels when they are configured with [RFC1918] or [RFC5735] WAN addresses. When configured with globally unique or Shared Address Space addresses, such devices may attempt to initiate 6to4, which would fail. Service Providers can mitigate this issue using 6to4 Provider Managed Tunnels [6to4-PMT] or blocking the route to 192.88.99.1 and generating an IPv4 'destination unreachable' message [RFC6343]. When the address range is well-defined, as with Shared Address Space, CPE router vendors can include Shared Address Space in their list of special-use addresses (e.g., [RFC5735]) and treat Shared Address Space similarly to [RFC1918] space. When the CGN-CPE address range is not well-defined, as in the case of globally unique space, it will be more difficult for CPE router vendors to mitigate this issue. Thus, when comparing the use of [RFC1918] and Shared Address Space, Shared Address Space poses an additional impact on 6to4 connectivity, which can be mitigated by Service Provider or CPE router vendor action. On the other hand, the use of [RFC1918] address space poses more of a challenge vis-a-vis Shared Address Space when the subscriber and Service Provider use overlapping [RFC1918] space, which will be outside the Service Provider's control in the case of unmanaged service. Service Providers have indicated that it is more challenging to mitigate the possibility of overlapping [RFC1918] address space on both sides of the CPE router than it is to mitigate the 6to4 impacts of Shared Address Space. 6. Security Considerations Similar to other [RFC5735] special-use IPv4 addresses, Shared Address Space does not directly raise security issues. However, the Internet does not inherently protect against abuse of these addresses. Attacks have been mounted that depend on the unexpected use of similar special-use addresses. Network operators are encouraged to review this document and determine what security policies should be associated with this address block within their specific operating environments. They should consider including Shared Address Space in Ingress Filter lists [RFC3704], unless their Internet service incorporates a CGN. Weil, et al. Best Current Practice [Page 7] RFC 6598 Shared Address Space Request April 2012 To mitigate potential misuse of Shared Address Space, except where required for hosted CGN service or a similar business relationship, o routing information about Shared Address Space networks MUST NOT be propagated across Service Provider boundaries. Service Providers MUST filter incoming advertisements regarding Shared Address Space. o packets with Shared Address Space source or destination addresses MUST NOT be forwarded across Service Provider boundaries. Service Providers MUST filter such packets on ingress links. o Service Providers MUST NOT include Shared Address Space in external-facing DNS zone files. o reverse DNS queries for Shared Address Space addresses MUST NOT be forwarded to the global DNS infrastructure. o DNS Providers SHOULD filter requests for Shared Address Space reverse DNS queries on recursive nameservers. 7. IANA Considerations IANA has recorded the allocation of an IPv4 /10 for use as Shared Address Space. The Shared Address Space address range is 100.64.0.0/10. 8. References 8.1. Normative References [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., de Groot, G., and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996. [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. Weil, et al. Best Current Practice [Page 8] RFC 6598 Shared Address Space Request April 2012 8.2. Informative References [6to4-PMT] Kuarsingh, V., Ed., Lee, Y., and O. Vautrin, "6to4 Provider Managed Tunnels", Work in Progress, February 2012. [ISP-SHARED-ADDR] Yamagata, I., Miyakawa, S., Nakagawa, A., Yamaguchi, J., and H. Ashida, "ISP Shared Address", Work in Progress, January 2012. [NAT444-IMPACTS] Donley, C., Howard, L., Kuarsingh, V., Berg, J., and J. Doshi, "Assessing the Impact of Carrier-Grade NAT on Network Applications", Work in Progress, November 2011. [PCP-BASE] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and P. Selkirk, "Port Control Protocol (PCP)", Work in Progress, March 2012. [RFC3704] Baker, F. and P. Savola, "Ingress Filtering for Multihomed Networks", BCP 84, RFC 3704, March 2004. [RFC6264] Jiang, S., Guo, D., and B. Carpenter, "An Incremental Carrier-Grade NAT (CGN) for IPv6 Transition", RFC 6264, June 2011. [RFC6269] Ford, M., Ed., Boucadair, M., Durand, A., Levis, P., and P. Roberts, "Issues with IP Address Sharing", RFC 6269, June 2011. [RFC6304] Abley, J. and W. Maton, "AS112 Nameserver Operations", RFC 6304, July 2011. [RFC6343] Carpenter, B., "Advisory Guidelines for 6to4 Deployment", RFC 6343, August 2011. Weil, et al. Best Current Practice [Page 9] RFC 6598 Shared Address Space Request April 2012 Appendix A. Acknowledgments Thanks to the following people (in alphabetical order) for their guidance and feedback: Stan Barber John Brzozowski Isaiah Connell Greg Davies Owen DeLong Kirk Erichsen Wes George Chris Grundemann Tony Hain Philip Matthews John Pomeroy Barbara Stark Jean-Francois Tremblay Leo Vegoda Steven Wright Ikuhei Yamagata Weil, et al. Best Current Practice [Page 10] RFC 6598 Shared Address Space Request April 2012 Authors' Addresses Jason Weil Time Warner Cable 13820 Sunrise Valley Drive Herndon, VA 20171 USA EMail: jason.weil@twcable.com Victor Kuarsingh Rogers Communications 8200 Dixie Road Brampton, ON L6T 0C1 Canada EMail: victor.kuarsingh@gmail.com Chris Donley CableLabs 858 Coal Creek Circle Louisville, CO 80027 USA EMail: c.donley@cablelabs.com Christopher Liljenstolpe Telstra Corp. 7/242 Exhibition Street Melbourne, VIC 316 Australia Phone: +61 3 8647 6389 EMail: cdl@asgaard.org Marla Azinger Frontier Communications Vancouver, WA USA Phone: +1.360.513.2293 EMail: marla.azinger@frontiercorp.com Weil, et al. Best Current Practice [Page 11] ========================================================================= Internet Engineering Task Force (IETF) M. Cotton Request for Comments: 6890 L. Vegoda BCP: 153 ICANN Obsoletes: 4773, 5156, 5735, 5736 R. Bonica, Ed. Category: Best Current Practice Juniper Networks ISSN: 2070-1721 B. Haberman JHU April 2013 Special-Purpose IP Address Registries Abstract This memo reiterates the assignment of an IPv4 address block (192.0.0.0/24) to IANA. It also instructs IANA to restructure its IPv4 and IPv6 Special-Purpose Address Registries. Upon restructuring, the aforementioned registries will record all special- purpose address blocks, maintaining a common set of information regarding each address block. This memo obsoletes RFCs 4773, 5156, 5735, and 5736. 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/rfc6890. Cotton, et al. Best Current Practice [Page 1] RFC 6890 Special-Purpose Address Registries April 2013 Copyright Notice Copyright (c) 2013 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. Table of Contents 1. Introduction ....................................................2 2. IANA Considerations .............................................3 2.1. Assignment of an IPv4 Address Block to IANA ................3 2.2. Restructuring of the IPv4 and IPv6 Special-Purpose Address ....................................................4 2.2.1. Information Requirements ............................4 2.2.2. IPv4 Special-Purpose Address Registry Entries .......6 2.2.3. IPv6 Special-Purpose Address Registry Entries ......14 3. Security Considerations ........................................20 4. Acknowledgements ...............................................20 5. Informative References .........................................20 1. Introduction In order to support new protocols and practices, the IETF occasionally reserves an address block for a special purpose. For example, [RFC1122] reserves an IPv4 address block (0.0.0.0/8) to represent the local (i.e., "this") network. Likewise, [RFC4291] reserves an IPv6 address block (fe80::/10) to represent link-scoped unicast addresses. Periodically, the IETF publishes an RFC that catalogs special-purpose address blocks. Currently, [RFC5735] catalogs all IPv4 special- purpose address blocks and [RFC5156] catalogs all IPv6 special- purpose address blocks. [RFC5736] assigns an IPv4 address block (192.0.0.0/24) to IANA and instructs IANA to allocate special-purpose address blocks from this space. [RFC5736] also instructs IANA to create an IPv4 Special- Purpose Address Registry that records allocations from this address Cotton, et al. Best Current Practice [Page 2] RFC 6890 Special-Purpose Address Registries April 2013 space. However, [RFC5736] does not instruct IANA to record special- purpose address block reservations from outside of the aforementioned space in the IPv4 Special-Purpose Address Registry. Likewise, [RFC2928] assigns an IPv6 address block (2001:0000::/23) to IANA and instructs IANA to allocate special-purpose address blocks from this space. [RFC4773] instructs IANA to create an IPv6 Special- Purpose Address Registry that records allocations from this address space. However, [RFC4773] does not instruct IANA to record special- purpose address block reservations from outside of the aforementioned space in the IPv6 Special-Purpose Address Registry. This memo reiterates the assignment of an IPv4 address block (192.0.0.0/24) to IANA. It also instructs IANA to restructure its IPv4 and IPv6 Special-Purpose Address Registries. Specifically, this memo instructs IANA to record all special-purpose address blocks in the aforementioned registries. These include, but are not limited to, IPv4 allocations from 192.0.0.0/24 and IPv6 allocations from 2001:0000::/23. Furthermore, this memo defines: o a common set of information that the registries will maintain regarding each special-purpose address block o a common set of requirements for future entries When the aforementioned registries include all special-purpose address blocks, [RFC5735] and [RFC5156] will become redundant with the registries. Therefore, this memo obsoletes [RFC5735] and [RFC5156]. Because this memo reiterates the assignment of 192.0.0.0/24 to IANA, and because it restructures the IPv4 Special- Purpose Address Registry, it obsoletes [RFC5736]. Finally, because this memo restructures the IPv6 Special-Purpose Address Registry, it obsoletes [RFC4773]. 2. IANA Considerations 2.1. Assignment of an IPv4 Address Block to IANA Table 7 of this document records the assignment of an IPv4 address block (192.0.0.0/24) to IANA for IETF protocol assignments. This address allocation to IANA is intended to support IETF protocol assignments. A more general view of the roles of IANA with respect to address allocation functions is documented in Sections 4.1 and 4.3 [RFC2860]. IANA has designated special-purpose address blocks in compliance with [RFC2860]. Cotton, et al. Best Current Practice [Page 3] RFC 6890 Special-Purpose Address Registries April 2013 2.2. Restructuring of the IPv4 and IPv6 Special-Purpose Address Registries IANA has restructured the following registries: o IPv4 Special-Purpose Address Registry o IPv6 Special-Purpose Address Registry The IPv4 Special-Purpose Address Registry records all IPv4 special- purpose address blocks. These reservations include, but are not limited to, allocations from the 192.0.0.0/24 address block. Likewise, the IPv6 Special-Purpose Address Registry records all IPv6 special-purpose address blocks. These reservations include, but are not limited to, allocations from the 2001:0000::/23 address block. Section 2.2.1 of this document describes information that both registries will maintain for each entry. Initially, IANA has populated the IPv4 Special-Purpose Address Registry with information taken from Section 2.2.2 of this document. Likewise, IANA has populated the IPv6 Special-Purpose Address Registry with information taken from Section 2.2.3 of this document. IANA will update the aforementioned registries as requested in the "IANA Considerations" section of a document that has passed IETF Review [RFC5226]. The "IANA Considerations" section must include all of the information specified in Section 2.2.1 of this document. 2.2.1. Information Requirements The IPv4 and IPv6 Special-Purpose Address Registries maintain the following information regarding each entry: o Address Block - A block of IPv4 or IPv6 addresses that has been registered for a special purpose. o Name - A descriptive name for the special-purpose address block. o RFC - The RFC through which the special-purpose address block was requested. o Allocation Date - The date upon which the special-purpose address block was allocated. o Termination Date - The date upon which the allocation is to be terminated. This field is applicable for limited-use allocations only. Cotton, et al. Best Current Practice [Page 4] RFC 6890 Special-Purpose Address Registries April 2013 o Source - A boolean value indicating whether an address from the allocated special-purpose address block is valid when used as the source address of an IP datagram that transits two devices. o Destination - A boolean value indicating whether an address from the allocated special-purpose address block is valid when used as the destination address of an IP datagram that transits two devices. o Forwardable - A boolean value indicating whether a router may forward an IP datagram whose destination address is drawn from the allocated special-purpose address block between external interfaces. o Global - A boolean value indicating whether an IP datagram whose destination address is drawn from the allocated special-purpose address block is forwardable beyond a specified administrative domain. o Reserved-by-Protocol - A boolean value indicating whether the special-purpose address block is reserved by IP, itself. This value is "TRUE" if the RFC that created the special-purpose address block requires all compliant IP implementations to behave in a special way when processing packets either to or from addresses contained by the address block. If the value of "Destination" is FALSE, the values of "Forwardable" and "Global" must also be false. Cotton, et al. Best Current Practice [Page 5] RFC 6890 Special-Purpose Address Registries April 2013 2.2.2. IPv4 Special-Purpose Address Registry Entries Tables 1 though 16, below, represent entries with which IANA has initially populated the IPv4 Special-Purpose Address Registry. +----------------------+----------------------------+ | Attribute | Value | +----------------------+----------------------------+ | Address Block | 0.0.0.0/8 | | Name | "This host on this network"| | RFC | [RFC1122], Section 3.2.1.3 | | Allocation Date | September 1981 | | Termination Date | N/A | | Source | True | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | True | +----------------------+----------------------------+ Table 1: "This host on this network" +----------------------+---------------+ | Attribute | Value | +----------------------+---------------+ | Address Block | 10.0.0.0/8 | | Name | Private-Use | | RFC | [RFC1918] | | Allocation Date | February 1996 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+---------------+ Table 2: Private-Use Networks Cotton, et al. Best Current Practice [Page 6] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------------+ | Attribute | Value | +----------------------+----------------------+ | Address Block | 100.64.0.0/10 | | Name | Shared Address Space | | RFC | [RFC6598] | | Allocation Date | April 2012 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------------+ Table 3: Shared Address Space +----------------------+----------------------------+ | Attribute | Value | +----------------------+----------------------------+ | Address Block | 127.0.0.0/8 | | Name | Loopback | | RFC | [RFC1122], Section 3.2.1.3 | | Allocation Date | September 1981 | | Termination Date | N/A | | Source | False [1] | | Destination | False [1] | | Forwardable | False [1] | | Global | False [1] | | Reserved-by-Protocol | True | +----------------------+----------------------------+ [1] Several protocols have been granted exceptions to this rule. For examples, see [RFC4379] and [RFC5884]. Table 4: Loopback Cotton, et al. Best Current Practice [Page 7] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------+ | Attribute | Value | +----------------------+----------------+ | Address Block | 169.254.0.0/16 | | Name | Link Local | | RFC | [RFC3927] | | Allocation Date | May 2005 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | False | | Global | False | | Reserved-by-Protocol | True | +----------------------+----------------+ Table 5: Link Local +----------------------+---------------+ | Attribute | Value | +----------------------+---------------+ | Address Block | 172.16.0.0/12 | | Name | Private-Use | | RFC | [RFC1918] | | Allocation Date | February 1996 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+---------------+ Table 6: Private-Use Networks Cotton, et al. Best Current Practice [Page 8] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+---------------------------------+ | Attribute | Value | +----------------------+---------------------------------+ | Address Block | 192.0.0.0/24 [2] | | Name | IETF Protocol Assignments | | RFC | Section 2.1 of this document | | Allocation Date | January 2010 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | False | +----------------------+---------------------------------+ [2] Not usable unless by virtue of a more specific reservation. Table 7: IETF Protocol Assignments +----------------------+--------------------------------+ | Attribute | Value | +----------------------+--------------------------------+ | Address Block | 192.0.0.0/29 | | Name | DS-Lite | | RFC | [RFC6333] | | Allocation Date | June 2011 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+--------------------------------+ Table 8: DS-Lite Cotton, et al. Best Current Practice [Page 9] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------------------+ | Attribute | Value | +----------------------+----------------------------+ | Address Block | 192.0.2.0/24 | | Name | Documentation (TEST-NET-1) | | RFC | [RFC5737] | | Allocation Date | January 2010 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------------------+ Table 9: TEST-NET-1 +----------------------+--------------------+ | Attribute | Value | +----------------------+--------------------+ | Address Block | 192.88.99.0/24 | | Name | 6to4 Relay Anycast | | RFC | [RFC3068] | | Allocation Date | June 2001 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | True | | Reserved-by-Protocol | False | +----------------------+--------------------+ Table 10: 6to4 Relay Anycast Cotton, et al. Best Current Practice [Page 10] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------+ | Attribute | Value | +----------------------+----------------+ | Address Block | 192.168.0.0/16 | | Name | Private-Use | | RFC | [RFC1918] | | Allocation Date | February 1996 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------+ Table 11: Private-Use Networks +----------------------+---------------+ | Attribute | Value | +----------------------+---------------+ | Address Block | 198.18.0.0/15 | | Name | Benchmarking | | RFC | [RFC2544] | | Allocation Date | March 1999 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+---------------+ Table 12: Network Interconnect Device Benchmark Testing Cotton, et al. Best Current Practice [Page 11] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------------------+ | Attribute | Value | +----------------------+----------------------------+ | Address Block | 198.51.100.0/24 | | Name | Documentation (TEST-NET-2) | | RFC | [RFC5737] | | Allocation Date | January 2010 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------------------+ Table 13: TEST-NET-2 +----------------------+----------------------------+ | Attribute | Value | +----------------------+----------------------------+ | Address Block | 203.0.113.0/24 | | Name | Documentation (TEST-NET-3) | | RFC | [RFC5737] | | Allocation Date | January 2010 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------------------+ Table 14: TEST-NET-3 Cotton, et al. Best Current Practice [Page 12] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------------+ | Attribute | Value | +----------------------+----------------------+ | Address Block | 240.0.0.0/4 | | Name | Reserved | | RFC | [RFC1112], Section 4 | | Allocation Date | August 1989 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | True | +----------------------+----------------------+ Table 15: Reserved for Future Use +----------------------+----------------------+ | Attribute | Value | +----------------------+----------------------+ | Address Block | 255.255.255.255/32 | | Name | Limited Broadcast | | RFC | [RFC0919], Section 7 | | Allocation Date | October 1984 | | Termination Date | N/A | | Source | False | | Destination | True | | Forwardable | False | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------------+ Table 16: Limited Broadcast Cotton, et al. Best Current Practice [Page 13] RFC 6890 Special-Purpose Address Registries April 2013 2.2.3. IPv6 Special-Purpose Address Registry Entries Tables 17 through 28, below, represent entries with which the IANA has initially populated the IPv6 Special-Purpose Address Registry. +----------------------+------------------+ | Attribute | Value | +----------------------+------------------+ | Address Block | ::1/128 | | Name | Loopback Address | | RFC | [RFC4291] | | Allocation Date | February 2006 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | True | +----------------------+------------------+ Table 17: Loopback Address +----------------------+---------------------+ | Attribute | Value | +----------------------+---------------------+ | Address Block | ::/128 | | Name | Unspecified Address | | RFC | [RFC4291] | | Allocation Date | February 2006 | | Termination Date | N/A | | Source | True | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | True | +----------------------+---------------------+ Table 18: Unspecified Address Cotton, et al. Best Current Practice [Page 14] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+---------------------+ | Attribute | Value | +----------------------+---------------------+ | Address Block | 64:ff9b::/96 | | Name | IPv4-IPv6 Translat. | | RFC | [RFC6052] | | Allocation Date | October 2010 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | True | | Reserved-by-Protocol | False | +----------------------+---------------------+ Table 19: IPv4-IPv6 Translation Address +----------------------+---------------------+ | Attribute | Value | +----------------------+---------------------+ | Address Block | ::ffff:0:0/96 | | Name | IPv4-mapped Address | | RFC | [RFC4291] | | Allocation Date | February 2006 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | True | +----------------------+---------------------+ Table 20: IPv4-Mapped Address Cotton, et al. Best Current Practice [Page 15] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------------------+ | Attribute | Value | +----------------------+----------------------------+ | Address Block | 100::/64 | | Name | Discard-Only Address Block | | RFC | [RFC6666] | | Allocation Date | June 2012 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------------------+ Table 21: Discard-Only Prefix +----------------------+---------------------------+ | Attribute | Value | +----------------------+---------------------------+ | Address Block | 2001::/23 | | Name | IETF Protocol Assignments | | RFC | [RFC2928] | | Allocation Date | September 2000 | | Termination Date | N/A | | Source | False[1] | | Destination | False[1] | | Forwardable | False[1] | | Global | False[1] | | Reserved-by-Protocol | False | +----------------------+---------------------------+ [1] Unless allowed by a more specific allocation. Table 22: IETF Protocol Assignments Cotton, et al. Best Current Practice [Page 16] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+----------------+ | Attribute | Value | +----------------------+----------------+ | Address Block | 2001::/32 | | Name | TEREDO | | RFC | [RFC4380] | | Allocation Date | January 2006 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------+ Table 23: TEREDO +----------------------+----------------+ | Attribute | Value | +----------------------+----------------+ | Address Block | 2001:2::/48 | | Name | Benchmarking | | RFC | [RFC5180] | | Allocation Date | April 2008 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+----------------+ Table 24: Benchmarking Cotton, et al. Best Current Practice [Page 17] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+---------------+ | Attribute | Value | +----------------------+---------------+ | Address Block | 2001:db8::/32 | | Name | Documentation | | RFC | [RFC3849] | | Allocation Date | July 2004 | | Termination Date | N/A | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | False | +----------------------+---------------+ Table 25: Documentation +----------------------+--------------+ | Attribute | Value | +----------------------+--------------+ | Address Block | 2001:10::/28 | | Name | ORCHID | | RFC | [RFC4843] | | Allocation Date | March 2007 | | Termination Date | March 2014 | | Source | False | | Destination | False | | Forwardable | False | | Global | False | | Reserved-by-Protocol | False | +----------------------+--------------+ Table 26: ORCHID Cotton, et al. Best Current Practice [Page 18] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+---------------+ | Attribute | Value | +----------------------+---------------+ | Address Block | 2002::/16 [2] | | Name | 6to4 | | RFC | [RFC3056] | | Allocation Date | February 2001 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | N/A [2] | | Reserved-by-Protocol | False | +----------------------+---------------+ [2] See [RFC3056] for details. Table 27: 6to4 +----------------------+--------------+ | Attribute | Value | +----------------------+--------------+ | Address Block | fc00::/7 | | Name | Unique-Local | | RFC | [RFC4193] | | Allocation Date | October 2005 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | True | | Global | False | | Reserved-by-Protocol | False | +----------------------+--------------+ Table 28: Unique-Local Cotton, et al. Best Current Practice [Page 19] RFC 6890 Special-Purpose Address Registries April 2013 +----------------------+-----------------------+ | Attribute | Value | +----------------------+-----------------------+ | Address Block | fe80::/10 | | Name | Linked-Scoped Unicast | | RFC | [RFC4291] | | Allocation Date | February 2006 | | Termination Date | N/A | | Source | True | | Destination | True | | Forwardable | False | | Global | False | | Reserved-by-Protocol | True | +----------------------+-----------------------+ Table 29: Linked-Scoped Unicast 3. Security Considerations Security of the Internet's routing system relies on the ability to authenticate an assertion of unique control of an address block. Measures to authenticate such assertions rely on validation that the address block forms part of an existing allocated address block and that there is a trustable and unique reference in the IANA address registries. The proposed registry is intended to provide an authoritative source of information regarding the currency and intended purpose of special purpose address blocks that are designated from the IANA-administered Special-Purpose registry. This is a small step towards the creation of a comprehensive registry framework that can be used as a trust point for commencing a chain of address validation. Consideration should be given to IANA registry publication formats that are machine parsable. Additionally, consideration should be given to the use of file signatures and associated certificate mechanisms to allow applications to confirm that the registry contents are current and that they have been published by the IANA. 4. Acknowledgements The authors thank Geoff Huston and Randy Bush for their helpful comments. The authors also express their gratitude to an anonymous donor, without whom this document would not have been written. 5. Informative References [RFC0919] Mogul, J., "Broadcasting Internet Datagrams", STD 5, RFC 919, October 1984. Cotton, et al. Best Current Practice [Page 20] RFC 6890 Special-Purpose Address Registries April 2013 [RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5, RFC 1112, August 1989. [RFC1122] Braden, R., Ed., "Requirements for Internet Hosts - Communication Layers", STD 3, RFC 1122, October 1989. [RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G., and E. Lear, "Address Allocation for Private Internets", BCP 5, RFC 1918, February 1996. [RFC2544] Bradner, S. and J. McQuaid, "Benchmarking Methodology for Network Interconnect Devices", RFC 2544, March 1999. [RFC2860] Carpenter, B., Baker, F., and M. Roberts, "Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority", RFC 2860, June 2000. [RFC2928] Hinden, R., Deering, S., Fink, R., and T. Hain, "Initial IPv6 Sub-TLA ID Assignments", RFC 2928, September 2000. [RFC3056] Carpenter, B. and K. Moore, "Connection of IPv6 Domains via IPv4 Clouds", RFC 3056, February 2001. [RFC3068] Huitema, C., "An Anycast Prefix for 6to4 Relay Routers", RFC 3068, June 2001. [RFC3849] Huston, G., Lord, A., and P. Smith, "IPv6 Address Prefix Reserved for Documentation", RFC 3849, July 2004. [RFC3927] Cheshire, S., Aboba, B., and E. Guttman, "Dynamic Configuration of IPv4 Link-Local Addresses", RFC 3927, May 2005. [RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast Addresses", RFC 4193, October 2005. [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006. [RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures", RFC 4379, February 2006. [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through Network Address Translations (NATs)", RFC 4380, February 2006. Cotton, et al. Best Current Practice [Page 21] RFC 6890 Special-Purpose Address Registries April 2013 [RFC4773] Huston, G., "Administration of the IANA Special Purpose IPv6 Address Block", RFC 4773, December 2006. [RFC4843] Nikander, P., Laganier, J., and F. Dupont, "An IPv6 Prefix for Overlay Routable Cryptographic Hash Identifiers (ORCHID)", RFC 4843, April 2007. [RFC5156] Blanchet, M., "Special-Use IPv6 Addresses", RFC 5156, April 2008. [RFC5180] Popoviciu, C., Hamza, A., Van de Velde, G., and D. Dugatkin, "IPv6 Benchmarking Methodology for Network Interconnect Devices", RFC 5180, May 2008. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC5735] Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses", RFC 5735, January 2010. [RFC5736] Huston, G., Cotton, M., and L. Vegoda, "IANA IPv4 Special Purpose Address Registry", RFC 5736, January 2010. [RFC5737] Arkko, J., Cotton, M., and L. Vegoda, "IPv4 Address Blocks Reserved for Documentation", RFC 5737, January 2010. [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, "Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)", RFC 5884, June 2010. [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, October 2010. [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- Stack Lite Broadband Deployments Following IPv4 Exhaustion", RFC 6333, August 2011. [RFC6598] Weil, J., Kuarsingh, V., Donley, C., Liljenstolpe, C., and M. Azinger, "IANA-Reserved IPv4 Prefix for Shared Address Space", BCP 153, RFC 6598, April 2012. [RFC6666] Hilliard, N. and D. Freedman, "A Discard Prefix for IPv6", RFC 6666, August 2012. Cotton, et al. Best Current Practice [Page 22] RFC 6890 Special-Purpose Address Registries April 2013 Authors' Addresses Michelle Cotton Internet Corporation for Assigned Names and Numbers (ICANN) 12025 Waterfront Drive, Suite 300 Los Angeles, CA 90094-2536 USA Phone: +310-823-9358 EMail: michelle.cotton@icann.org URI: http://www.icann.org/ Leo Vegoda Internet Corporation for Assigned Names and Numbers (ICANN) 12025 Waterfront Drive, Suite 300 Los Angeles, CA 90094-2536 USA Phone: +310-823-9358 EMail: leo.vegoda@icann.org URI: http://www.icann.org/ Ronald P Bonica (editor) Juniper Networks 2251 Corporate Park Drive Herndon, VA 20171 USA EMail: rbonica@juniper.net Brian Haberman Johns Hopkins University (JHU) Applied Physics Lab 11100 Johns Hopkins Road Laurel, MD 20723-6099 USA EMail: brian@innovationslab.net Cotton, et al. Best Current Practice [Page 23]