IPv6 Special-Purpose Address Space

Created

  • 2006-01-10

Last Updated

  • 2025-10-09

Available Formats


IPv6 Special-Purpose Address Space

Registration Procedure(s)

  • IETF Review

Reference

  • RFC 4773: Administration of the IANA Special Purpose IPv6 Address Block
  • RFC 6890: Special-Purpose IP Address Registries
  • RFC 8190: Updates to the Special-Purpose IP Address Registries

Note

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:

  • Address Block - A block of IPv4 or IPv6 addresses that has been registered for a special purpose.

  • Name - A descriptive name for the special-purpose address block.

  • RFC - The RFC through which the special-purpose address block was requested.

  • Allocation Date - The date upon which the special-purpose address block was allocated.

  • Termination Date - The date upon which the allocation is to be terminated. This field is applicable for limited-use allocations only.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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 IPv6 Special-Purpose Address Registry (pursuant to IESG decision)

Available Formats

Address Block Name RFC Allocation Date Termination Date Source Destination Forwardable Globally Reachable Reserved-by-Protocol
::1/128 Loopback Address RFC 4291 2006-02 N/A False False False False True
::/128 Unspecified Address RFC 4291 2006-02 N/A True False False False True
::ffff:0:0/96 IPv4-mapped Address RFC 4291 2006-02 N/A False False False False True
64:ff9b::/96 IPv4-IPv6 Translat. RFC 6052 2010-10 N/A True True True True False
64:ff9b:1::/48 IPv4-IPv6 Translat. RFC 8215 2017-06 N/A True True True False False
100::/64 Discard-Only Address Block RFC 6666 2012-06 N/A True True True False False
100:0:0:1::/64 Dummy IPv6 Prefix RFC 9780 2025-04 N/A True False False False False
2001::/23 IETF Protocol Assignments RFC 2928 2000-09 N/A False [1] False [1] False [1] False [1] False
2001::/32 TEREDO RFC 4380; RFC 8190 2006-01 N/A True True True N/A [2] False
2001:1::1/128 Port Control Protocol Anycast RFC 7723 2015-10 N/A True True True True False
2001:1::2/128 Traversal Using Relays around NAT Anycast RFC 8155 2017-02 N/A True True True True False
2001:1::3/128 DNS-SD Service Registration Protocol Anycast RFC 9665 2024-04 N/A True True True True False
2001:2::/48 Benchmarking RFC 5180; RFC Errata 1752 2008-04 N/A True True True False False
2001:3::/32 AMT RFC 7450 2014-12 N/A True True True True False
2001:4:112::/48 AS112-v6 RFC 7535 2014-12 N/A True True True True False
2001:10::/28 Deprecated (previously ORCHID) RFC 4843 2007-03 2014-03
2001:20::/28 ORCHIDv2 RFC 7343 2014-07 N/A True True True True False
2001:30::/28 Drone Remote ID Protocol Entity Tags (DETs) Prefix RFC 9374 2022-12 N/A True True True True False
2001:db8::/32 Documentation RFC 3849 2004-07 N/A False False False False False
2002::/16 [3] 6to4 RFC 3056 2001-02 N/A True True True N/A [3] False
2620:4f:8000::/48 Direct Delegation AS112 Service RFC 7534 2011-05 N/A True True True True False
3fff::/20 Documentation RFC 9637 2024-07 N/A False False False False False
5f00::/16 Segment Routing (SRv6) SIDs RFC 9602 2024-04 N/A True True True False False
fc00::/7 Unique-Local RFC 4193; RFC 8190 2005-10 N/A True True True False [4] False
fe80::/10 Link-Local Unicast RFC 4291 2006-02 N/A True True False False True

Footnotes

[1]

Unless allowed by a more specific allocation.

[2]

See Section 5 of RFC 4380 for details.

[3]

See RFC 3056 for details.

[4]

See RFC 4193 for more details on the routability of Unique-Local addresses. The Unique-Local prefix is drawn from the IPv6 Global Unicast Address range, but is specified as not globally routed.