RFC 3330 (rfc3330) - Page 2 of 7

Special-Use IPv4 Addresses

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RFC 3330               Special-Use IPv4 Addresses         September 2002


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 [RFC 1700, page 4].

   10.0.0.0/8 - This block is set aside for use in private networks.
   Its intended use is documented in [RFC 1918].  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 [RFC 1700, 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 [RFC 1797].  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 [RFC 1700, page 5].

   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.





IANA                         Informational
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