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                                                                  IPv6 Address Space

Last Updated
        2025-10-23

Note

 The IPv6 address management function was formally delegated to IANA
 in December 1995 [RFC 1881]. The registration procedure was confirmed
 with the IETF Chair in March 2010.

 As stated in [RFC 3513], 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 [RFC 3513] was obsoleted by [RFC 4291], the guidance provided to
 IANA did not change regarding the allocation of IPv6 unicast
 addresses.



Formerly known as

 Internet Protocol Version 6 Address Space (pursuant to [IESG decision])

Available Formats
        [IMG]
        XML [IMG]
        HTML [IMG]
        TXT

Registration Procedure(s)

             IETF Review


Reference
        [RFC 9812]

Available Formats
        [IMG]
        CSV

IPv6 Prefix      Allocation            Reference                                                    Notes
                                                        This range has been partially allocated. See [IPv6 Special-Purpose Address Space] for details.
::/8        Reserved by IETF     [RFC 3513]; [RFC 4291] ::/96, formerly defined as the "IPv4-compatible IPv6 address" prefix, was deprecated by [RFC
                                                        4291].
100::/8     Reserved by IETF     [RFC 3513]; [RFC 4291] This range has been partially allocated. See [IPv6 Special-Purpose Address Space] for details.
200::/7     Reserved by IETF     [RFC 4048]             Deprecated as of December 2004 [RFC 4048]. Formerly an OSI NSAP-mapped prefix set [RFC 4548].
400::/6     Reserved by IETF     [RFC 3513]; [RFC 4291]
800::/5     Reserved by IETF     [RFC 3513]; [RFC 4291]
1000::/4    Reserved by IETF     [RFC 3513]; [RFC 4291]
                                                        The IPv6 Unicast space encompasses the entire IPv6 address range with the exception of
2000::/3    Global Unicast       [RFC 3513]; [RFC 4291] ff00::/8, per [RFC 4291]. IANA unicast address assignments are currently limited to the IPv6
                                                        unicast address range of 2000::/3. IANA assignments from this block are registered in [IPv6
                                                        Global Unicast Address Space].
                                                        This range has been partially allocated. See [IPv6 Special-Purpose Address Space] for details.
4000::/3    Reserved by IETF     [RFC 3513]; [RFC 4291] 5f00::/8 (with 3ffe::/16, as noted at [IPv6 Global Unicast Address Space]) was used for the
                                                        6bone, but returned [RFC 5156].
6000::/3    Reserved by IETF     [RFC 3513]; [RFC 4291]
8000::/3    Reserved by IETF     [RFC 3513]; [RFC 4291]
a000::/3    Reserved by IETF     [RFC 3513]; [RFC 4291]
c000::/3    Reserved by IETF     [RFC 3513]; [RFC 4291]
e000::/4    Reserved by IETF     [RFC 3513]; [RFC 4291]
f000::/5    Reserved by IETF     [RFC 3513]; [RFC 4291]
f800::/6    Reserved by IETF     [RFC 3513]; [RFC 4291]
fc00::/7    Unique Local Unicast [RFC 4193]             See [IPv6 Special-Purpose Address Space] for details.
fe00::/9    Reserved by IETF     [RFC 3513]; [RFC 4291]
fe80::/10   Link-Scoped Unicast  [RFC 3513]; [RFC 4291] See [IPv6 Special-Purpose Address Space] for details.
fec0::/10   Reserved by IETF     [RFC 3879]             Deprecated by [RFC 3879] in September 2004. Formerly a Site-Local scoped address prefix.
ff00::/8    Multicast            [RFC 3513]; [RFC 4291] See [IPv6 Multicast Address Space] for details.

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