Internet DRAFT - draft-iana-special-ipv4

draft-iana-special-ipv4



Network Working Group                                               IANA
Internet-Draft                                            August 9, 2002
Expires: February 9, 2003

draft-iana-special-ipv4-05.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 October 22, 2002.

Copyright Notice

   Copyright (C) The Internet Society (2002). All Rights Reserved.


Abstract

   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 (the IANA) 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 according to their established needs.  These


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   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 [RFC1700, page 4].

   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
   should not appear on the public Internet.

   14.0.0.0/8 - This block is set aside for assignments to the
   international system of Public Data Networks [RFC1700, page 181]. 
   The registry of assignments within this block can be accessed from 
   the "Public Data Network Numbers" link on the web page at  
   http://www.iana.org/numbers.html.  Addresses within this block are 
   assigned to users and should be treated as such.

   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.  Addresses within this block are assigned 
   in the normal manner and should be treated as such.

   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.  This
   block therefore no longer has a special use and is subject to 
   allocation to a Regional Internet Registry for assignment in the 
   normal manner.

   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 within this block should ever appear on any network
   anywhere [RFC1700, page 5].

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   128.0.0.0/16 - This block, corresponding to the numerically lowest of
   the former Class B addresses, was initially and is still reserved by 
   the IANA.  Given the present classless nature of the IP address space,
   the basis for the reservation no longer applies and addresses in this 
   block are subject to future allocation to a Regional Internet Registry 
   for assignment in the normal manner.

   169.254.0.0/16 - This is the "link local" block. It is allocated for
   communication between hosts on a single link.  Hosts obtain these
   addresses by auto-configuration, such as 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 should not appear on the public Internet.

   191.255.0.0/16 - This block, corresponding to the numerically highest
   to the former Class B addresses, was initially and is still reserved by 
   the IANA.  Given the present classless nature of the IP address space,
   the basis for the reservation no longer applies and addresses in this 
   block are subject to future allocation to a Regional Internet Registry 
   for assignment in the normal manner.

   192.0.0.0/24 - This block, corresponding to the nummerically lowest
   of the former Class C addresses, was initially and is still reserved 
   by the IANA.  Given the present classless nature of the IP address 
   space, the basis for the reservation no longer applies and addresses 
   in this block are subject to future allocation to a Regional Internet 
   Registry for assignment in the normal manner.

   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.  Addresses within this block should not appear on the 
   public Internet.

   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 should not appear 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].

   223.255.255.0/24 - This block, corresponding to the numerically 
   highest of the former Class C addresses, was initially and is still 
   reserved by the IANA.  Given the present classless nature of the IP 
   address space, the basis for the reservation no longer applies and 
   addresses in this block are subject to future allocation to a 
   Regional Internet Registry for assignment in the normal manner.


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   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 [RFC3171].

   240.0.0.0/4 - This block, formerly known as the Class E address 
   space, is reserved. The "limited broadcast" destination address 
   255.255.255.255 should never be forwarded outside the (sub-)net of 
   the source.  The remainder of this space is reserved for future use.
   [RFC1700, page 4]


3. Summary Table

   Address Block              Present Use                       Reference
   ----------------------------------------------------------------------
   0.0.0.0/8             "This" Network                 [RFC1700, page 4]
   10.0.0.0/8            Private-Use Networks                   [RFC1918]
   14.0.0.0/8            Public-Data Networks         [RFC1700, page 181]
   24.0.0.0/8            Cable Television Networks                    --
   39.0.0.0/8            Reserved but subject 
                           to allocation                        [RFC1797]
   127.0.0.0/8           Loopback                       [RFC1700, page 5]
   128.0.0.0/16          Reserved but subject 
                           to allocation                              --
   169.254.0.0/16        Link Local                                   --
   172.16.0.0/12         Private-Use Networks                   [RFC1918]
   191.255.0.0/16        Reserved but subject 
                           to allocation                              --
   192.0.0.0/24          Reserved but subject 
                           to allocation                              --
   192.0.2.0/24          Test-Net
   192.88.99.0/24        6to4 Relay Anycast                     [RFC3068]
   192.168.0.0/16        Private-Use Networks                   [RFC1918]
   198.18.0.0/15         Network Interconnect 
                           Device Benchmark Testing             [RFC2544]
   223.255.255.0/24      Reserved but subject 
                           to allocation                              --
   224.0.0.0/4           Multicast                              [RFC3171]
   240.0.0.0/4           Reserved for Future Use        [RFC1700, page 4]


4. 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.


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   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.  Nonetheless, 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], the IANA will also make necessary 
   experimental assignments of IPv4 addresses, also in consultation 
   with the Regional Internet Registries.

5. Security Considerations

   The particular assigned values of special-use IPv4 addresses 
   cataloged in this document do not directly raise security issues.  
   However, the Internet does not inherently protect against abuse of
   these addresses; if you expect (for instance) that all packets from
   the 10.0.0.0/8 block originate within your subnet, all border 
   routers should filter such packets that originate from elsewhere.
   Attacks have been mounted that depend on the unexpected use of some 
   of these addresses.

6. 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.


7. 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.

   [RFC1700] Reynolds, J. and Postel, J., "Assigned Numbers", RFC 1700, 
   October 1994 (now historic).

   [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.


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   [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.

8. Acknowledgments

   The IANA would like to thank Scott Bradner, Randy Bush, and Harald
   Alvestrand for their constructive feedback and comments.

9. 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


10. Full Copyright Statement

   Copyright (C) The Internet Society (date). All Rights Reserved.


   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.



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