Internet Assigned Numbers Authority

                                                      Internet Protocol Version 6 Address Space

   Last Updated
   2024-09-10

   Note

 The IPv6 address management function was formally delegated to IANA
 in December 1995 [RFC1881]. The registration procedure was confirmed
 with the IETF Chair in March 2010.

 As stated in [RFC3513], IANA should limit its allocation of
 IPv6-unicast address space to the range of addresses that start with
 binary value 001. The rest of the global unicast address space
 (approximately 85% of the IPv6 address space) is reserved for future
 definition and use, and is not to be assigned by IANA at this time.

 While [RFC3513] was obsoleted by [RFC4291], the guidance provided to
 IANA did not change regarding the allocation of IPv6 unicast
 addresses.



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   Registration Procedure(s)

 IESG Approval

   Available Formats
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   IPv6 Prefix      Allocation          Reference                                                 Notes
                                                       This range has been partially allocated. See [IANA registry iana-ipv6-special-registry] for
   ::/8        Reserved by IETF     [RFC3513][RFC4291] details. ::/96, formerly defined as the "IPv4-compatible IPv6 address" prefix, was
                                                       deprecated by [RFC4291].
   100::/8     Reserved by IETF     [RFC3513][RFC4291] This range has been partially allocated. See [IANA registry iana-ipv6-special-registry] for
                                                       details.
   200::/7     Reserved by IETF     [RFC4048]          Deprecated as of December 2004 [RFC4048]. Formerly an OSI NSAP-mapped prefix set [RFC4548].
   400::/6     Reserved by IETF     [RFC3513][RFC4291]
   800::/5     Reserved by IETF     [RFC3513][RFC4291]
   1000::/4    Reserved by IETF     [RFC3513][RFC4291]
                                                       The IPv6 Unicast space encompasses the entire IPv6 address range with the exception of
   2000::/3    Global Unicast       [RFC3513][RFC4291] ff00::/8, per [RFC4291]. IANA unicast address assignments are currently limited to the IPv6
                                                       unicast address range of 2000::/3. IANA assignments from this block are registered in [IANA
                                                       registry ipv6-unicast-address-assignments].
                                                       This range has been partially allocated. See [IANA registry iana-ipv6-special-registry] for
   4000::/3    Reserved by IETF     [RFC3513][RFC4291] details. 5f00::/8 (with 3ffe::/16, as noted at [IANA registry
                                                       ipv6-unicast-address-assignments]) was used for the 6bone, but returned [RFC5156].
   6000::/3    Reserved by IETF     [RFC3513][RFC4291]
   8000::/3    Reserved by IETF     [RFC3513][RFC4291]
   a000::/3    Reserved by IETF     [RFC3513][RFC4291]
   c000::/3    Reserved by IETF     [RFC3513][RFC4291]
   e000::/4    Reserved by IETF     [RFC3513][RFC4291]
   f000::/5    Reserved by IETF     [RFC3513][RFC4291]
   f800::/6    Reserved by IETF     [RFC3513][RFC4291]
   fc00::/7    Unique Local Unicast [RFC4193]          See [IANA registry iana-ipv6-special-registry] for details.
   fe00::/9    Reserved by IETF     [RFC3513][RFC4291]
   fe80::/10   Link-Scoped Unicast  [RFC3513][RFC4291] See [IANA registry iana-ipv6-special-registry] for details.
   fec0::/10   Reserved by IETF     [RFC3879]          Deprecated by [RFC3879] in September 2004. Formerly a Site-Local scoped address prefix.
   ff00::/8    Multicast            [RFC3513][RFC4291] See [IANA registry ipv6-multicast-addresses] for details.

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