Network Working Group IANA Internet-Draft February 21, 2002 Expires: August 21, 2002 draft-iana-special-ipv4-00.txt Special-Use IPv4 Addresses Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of [RFC2026]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 21, 2002. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract The Internet Assigned Numbers Authority (the IANA) is responsible for assignment of parameter values within identifier spaces used in the Internet, including the Internet Protocol Version 4 (IPv4) address space. The IANA allocates parts of the IPv4 space to Regional Internet Registries, which are delegated the responsibility for the assignment of IPv4 addresses to operators and users of the Internet within their regions. In addition to these assignments, the IANA is IANA Expires August 21, 2002 [Page 1] DRAFT Special-Use IPv4 Addresses February 2002 responsible for allocating IPv4 space for global and other specialized address blocks. This document describes the global and other specialized IPv4 address blocks that have been assigned by the IANA. It does not address IPv4 address space assigned to operators and users through the Regional Internet Registries. It also does not address allocations or assignments of IPv6 addresses or autonomous system numbers. 1. Introduction Throughout its entire history, the Internet has employed a central Internet Assigned Numbers Authority responsible for the allocation and assignment of various identifiers needed for the operation of the Internet [RFC1174]. In the case of the IPv4 address space, the IANA allocates parts of the address space to Regional Internet Registries (currently there are three) according to their established needs. These Regional Internet Registries are responsible for the assignment of IPv4 addresses to operators and users of the Internet within their regions. Minor portions of the IPv4 address space have been allocated or assigned directly by the IANA for global or other specialized purposes. These allocations and assignments have been documented in a variety of RFCs and other documents. This document is intended to collect these scattered references. On an ongoing basis, the IANA has been designated by the IETF to make assignments in support of the Internet Standards Process [RFC2860]. Section 3 of this document describes that assignment process. 2. Global and Other Specialized Address Blocks 0.0.0.0/8 - Addresses in this block refer to source hosts on "this" network. Address 0.0.0.0/32 may be used as a source address for this host on this network; other addresses within 0.0.0.0/8 may be used to refer to specified hosts on this network. 10.0.0.0/8 - This block is set aside for use in private networks. Its intended use is documented in [RFC1918]. Addresses within this block are not routable on the public Internet. 14.0.0.0/8 - This block is set aside for assignments to the international system of Public Data Networks. The registry of assignments within this block can be accessed from the "Public Data IANA Expires August 21, 2002 [Page 2] DRAFT Special-Use IPv4 Addresses February 2002 Network Numbers" link on the web page at http://www.iana.org/numbers.html. 24.0.0.0/8 - This block was allocated in early 1996 for use in provisioning IP service over cable television systems. Although the IANA initially was involved in making assignments to cable operators, this responsibility was transferred to American Registry for Internet Numbers (ARIN) in May 2001. 39.0.0.0/8 - This block was used in the "Class A Subnet Experiment" that commenced in May 1995, as documented in [RFC1797]. The experiment has been completed and this block has been returned to the pool of addresses reserved for future allocation or assignment. 127.0.0.0/8 - This block is assigned for use as the Internet host loopback address. A datagram sent by a higher level protocol to an address anywhere within this block should loop back inside the host. This is ordinarily implemented using only 127.0.0.1/32 for loopback, but no addresses in this block should ever appear on any network anywhere. 169.254.0.0/16 - This is the "linklocal" block. It is allocated for use in end node auto-configuration when a DHCP server may not be found. 172.16.0.0/12 - This block is set aside for use in private networks. Its intended use is documented in [RFC1918]. Addresses within this block are not routable on the public Internet. 192.0.2.0/24 - This block is assigned as "TEST-NET" for use in documentation and example code. It is often used in conjunction with domain names example.com or example.net in vendor and protocol documentation. 192.88.99.0/24 - This block is allocated for use as 6to4 relay anycast addresses, according to [RFC3068]. 192.168.0.0/16 - This block is set aside for use in private networks. Its intended use is documented in [RFC1918]. Addresses within this block are not routable on the public Internet. 198.18.0.0/15 - This block has been allocated for use in benchmark tests of network interconnect devices. Its use is documented in [RFC2544]. 224.0.0.0/4 - This block, formerly known as the Class D address space, is allocated for use in IPv4 multicast address assignments. The IANA guidelines for assignments from this space are described in IANA Expires August 21, 2002 [Page 3] DRAFT Special-Use IPv4 Addresses February 2002 [RFC3171]. 240.0.0.0/4 - This block, formerly known as the Class E address space, is reserved for future use. The "limited broadcast" destination address 255.255.255.255 must never be forwarded outside the (sub-)net of the source. 3. Assignments of IPv4 Blocks for New Specialized Uses The IANA has responsibilty for making assignments of protocol parameters used in the Internet according to the requirements of the "Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority". [RFC2860] Among other things, [RFC2860] requires that protocol parameters be assigned according to the criteria and procedures specified in RFCs, including Proposed, Draft and full Internet Standards and Best Current Practice documents, and any other RFC that calls for IANA assignment. Although the domain name and IP address spaces involve policy issues (in addition to technical issues) so that the requirements of [RFC2860] do not apply generally to those spaces, the IANA is responsible for ensuring assignments of IPv4 addresses as needed in support of the Internet Standards Process. When a portion of the IPv4 address space is specifically required by an RFC, the technical requirements (e.g., size, prefix length) for the portion should be described. [RFC2434] Immediately before the RFC is published, the IANA will, in consultation with the Regional Internet Registries, make the necessary assignment and notify the RFC Editor of the particulars for inclusion in the RFC as published. As required by [RFC2860], IANA will also make necessary experimental assignments of IPv4 addresses, also in consultation with the Regional Internet Registries. 4. Security Considerations The particular assigned values of special-use IPv4 addresses cataloged in this document do not directly raise security issues. However, awareness of these special assignments offers the ability to detect inappropriate IPv4 addresses within packets on the public Internet. 5. IANA Considerations This document describes the IANA's past and current practices and does not create any new requirements for assignments or allocations by the IANA. IANA Expires June 01, 2002 [Page 4] DRAFT Special-Use IPv4 Addresses February 2002 6. References [RFC1174] Cerf, V., "IAB Recommended Policy on Distributing Internet Identifier Assignment and IAB Recommended Policy Change to Internet 'Connected' Status", RFC 1174, August 1990. [RFC1797] IANA, "Class A Subnet Experiment", RFC 1797, April 1995. [RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G. J., and Lear, E., "Address Allocation for Private Internets", RFC 1918, February 1996. [RFC2050] Hubbard, K., Kosters, M., Conrad, D., Karrenberg, D., and Postel, J., "Internet Registry IP Allocation Guidelines:, BCP 12, RFC 2050, November 1996. [RFC2434] Narten, T., and Alvestrand, H., "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. [RFC2544] Bradner, S., and McQuaid, J., "Benchmarking Methodology for Network Interconnect Devices", RFC 2544, March 1999. [RFC2860] Carpenter, B., Baker, F., and Roberts, M., "Memorandum of Understanding Concerning the Technical Work of the Internet Assigned Numbers Authority", RFC 2860, June 2000. [RFC3068] Huitema, C., "An Anycast Prefix for 6to4 Relay Routers", RFC 3068, June 2001. [RFC3171] Albanna, Z., Almeroth, K., Meyer, D., and Schipper, M., "IANA Guidelines for IPv4 Multicast Address Assignments", BCP 51, RFC 3171, August 2001. 7. Author's Address Internet Assigned Numbers Authority (IANA) 4676 Admiralty Way, Suite 330 Marina del Rey, CA 90292-6601 Phone: +1 310-823-9358 Fax: +1 310-823-8649 E-mail: iana@iana.org 8. Full Copyright Statement Copyright (C) The Internet Society (date). All Rights Reserved. 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