Special-Use IPv4 Addresses
RFC 3330

Document Type RFC - Informational (October 2002; Errata)
Obsoleted by RFC 5735
Author IANA 
Last updated 2015-10-14
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IESG IESG state RFC 3330 (Informational)
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Network Working Group                                               IANA
Request for Comments: 3330                                September 2002
Category: Informational

                       Special-Use IPv4 Addresses

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

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


   This document describes the global and other specialized IPv4 address
   blocks that have been assigned by the Internet Assigned Numbers
   Authority (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 (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
   Regional Internet Registries are responsible for the assignment of
   IPv4 addresses to operators and users of the Internet within their

   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 4 of this document describes that assignment process.

IANA                         Informational                      [Page 1]
RFC 3330               Special-Use IPv4 Addresses         September 2002

2. Global and Other Specialized Address Blocks - Addresses in this block refer to source hosts on "this"
   network.  Address may be used as a source address for this
   host on this network; other addresses within may be used to
   refer to specified hosts on this network [RFC1700, page 4]. - 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. - 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. - 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. - 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. - 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 for loopback,
   but no addresses within this block should ever appear on any network
   anywhere [RFC1700, page 5]. - 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.

IANA                         Informational                      [Page 2]
RFC 3330               Special-Use IPv4 Addresses         September 2002 - This is the "link local" block.  It is allocated for
   communication between hosts on a single link.  Hosts obtain these
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