IPv4 Special-Purpose Address Space

Created

2009-08-19

Last Updated

2025-10-09

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Registry Included Below

• IPv4 Special-Purpose Address Space

IPv4 Special-Purpose Address Space

Registration Procedure(s)

IETF Review

Reference

[RFC 5736][RFC 6890][RFC Errata 6404][RFC 8190]

Note

The IETF has reserved the address block of 192.0.0.0/24 for use for
special purposes relating to protocol assignments. This registry
contains the current assignments made by the IETF from this address
block.

Address prefixes listed in the Special-Purpose Address Registry are
not guaranteed routability in any particular local or global context.

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.

   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  Globally Reachable - 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 "Globally Reachable" must also be false.
    

Formerly known as

IANA IPv4 Special-Purpose Address Registry (pursuant to [IESG decision])

Available Formats

CSV

Footnotes

Several protocols have been granted exceptions to this rule. 
For examples, see [RFC 8029] and [RFC 5884].

Not useable unless by virtue of a more specific reservation.