Some unofficial notes on IPv6 prefixes and address

Updated: 2023-11-20
Created: 2003-12-18

Addressing information from many sources, like:

General note on unicast addresses: the first 16 bits are the TLA, the next 8 bits must be zero, then 24 bits of NLA (48 bits total), 16 bits of SLA (64 bits total), and 64 bits for the interface.

The first 64 bits are the network prefix routeable, the last 64 bits are the interface identifier and can be ignored by routers.

Also, there are issues on internet-wide routes and the length of prefixes. Someone has written some recommendations which illustrate what is expected to be routeable.

The table below is supposed to be exhaustive.

Note: the special address ending ":!" is supposed to be 1 bits to the lest significant bit, to make end-of-ranges more compact.

IPv6 unicast and anycast address ranges
Prefix Up to Notes
0000::/3 01ff:!/3 Non interface based addresses
0000::/8 00ff:!/8 Reserved
0000::0000/128 0000::0000/128 node local: unspecified address
0000::0001/128 0000::0001/128 node local: localhost
0000::0000:0000:0000/96 0000::0000:ffff:ffff/96 obsolete: IPv4 compatible
0000::ffff:0000:0000/96 0000::ffff:ffff:ffff/96 IPv4 mapped
0064:ff9b:0000::0000:0000/96 0064:ff9b:0000::ffff:ffff/96 NAT64
0064:ff9b:0001::/48 0064:ff9b:0001:!/48 NAT64
0100::/8 01ff:!/8 unassigned
0100::/8 01ff:!/8 unassigned
0200::/7 03ff:!/7 NSAP
0400::/7 05ff:!/7 obsolete: IPX
0600::/7 07ff:!/7 unassigned
0800::/5 0fff:!/5 unassigned
1000::/4 1fff:!/4 unassigned
2000::/3 3fff:!/3 aggregatable global
4000::/3 5fff:!/3 unassigned
6000::/3 7fff:!/3 unassigned
8000::/3 9fff:!/3 unassigned
a000::/3 bfff:!/3 unassigned
c000::/3 dfff:!/3 unassigned
e000::/4 efff:!/4 unassigned
f000::/5 f7ff:!/5 unassigned
f800::/7 f9ff:!/7 unassigned
fa00::/7 fbff:!/7 unassigned
fc00::/8 fcff:!/8 unique local reserved
fd00::/8 fdff:!/8 unique local random /48 subnets
fe00::/9 fe7f:!/9 unassigned
fe80::/10 febf:!/10 link local
fec0::/10 feff:!/10 obsolete: site local
IPv6 aggregatable global address allocations
Prefix Up to Notes
2000:0000::/16 2000:ffff:!/16 reserved
2001:0000::/23 2001:01ff:!/23 sub TLAs: IANA
2001:0000::/32 2001:0000:!/32 Teredo, non Microsoft (official)
2001:0200::/23 2001:03ff:!/23 sub TLAs: APNIC
2001:0400::/23 2001:05ff:!/23 sub TLAs: ARIN
2001:0600::/23 2001:07ff:!/23 sub TLAs: RIPE NCC
2001:0678::/29 2001:067f:!/29 sub TLAs: PIAS subnets.
2001:07f8::/29 2001:07ff:!/29 sub TLAs: IXP subnets.
2001:0800::/23 2001:09ff:!/23 sub TLAs: RIPE NCC
2001:0a00::/23 2001:0bff:!/23 sub TLAs: RIPE NCC
2001:0c00::/23 2001:0dff:!/23 sub TLAs: APNIC
2001:0db8::/32 2001:0db8:!/32 sub TLAs: example addresses (will not be allocated).
2001:0e00::/23 2001:0fff:!/23 sub TLAs: APNIC
2001:1200::/23 2001:13ff:!/23 sub TLAs: LACNIC
2001:1400::/23 2001:15ff:!/23 sub TLAs: RIPE NCC
2001:1600::/23 2001:17ff:!/23 sub TLAs: RIPE NCC
2001:1800::/23 2001:19ff:!/23 sub TLAs: ARIN
2002::/16 2002:!/16 6to4
2400::/12 24ff:!/12 sub TLAs: APNIC
2600::/12 26ff:!/12 sub TLAs: ARIN
2800::/12 28ff:!/12 sub TLAs: LACNIC
2a00::/12 2aff:!/12 sub TLAs: RIPE NCC
2c00::/12 2cff:!/12 sub TLAs: AfriNIC
3ffe::/16 3ffe:!/16 obsolete: 6bone pseudo TLAs
3ffe:831f::/32 3ffe:831f:!/32 obsolete: Teredo, Microsoft (experimental)
3fff::/16 3fff:!/16 reserved

The multicast table below is exhaustive, except that any ranges not described in the fourth hex digit are reserved.

IPv6 multicast address ranges
Prefix Up to Notes
ff00::/8 ffff:!/8 multicast
ff00::/12 ff0f:!/12 well known
ff01::/16 ff01:!/16 well known link local
ff02::/16 ff02:!/16 well known site local
ff02:0:0:0:0:1:ff00::/104 ff02:0:0:0:0:1:ffff::/104 well known solicited-node
ff05::/16 ff05:!/16 well known site local
ff08::/16 ff08:!/16 well known organization local
ff0e::/16 ff0e:!/16 well known global
ff10::/12 ff1f:!/12 transient
ff11::/16 ff11:!/16 transient link local
ff12::/16 ff12:!/16 transient site local
ff15::/16 ff15:!/16 transient site local
ff18::/16 ff18:!/16 transient organization local
ff1e::/16 ff1e:!/16 transient global
ff20::/12 ff2f:!/12 unassigned
ff30::/12 ff3f:!/12 RFC 3306 prefix based multicast
ff30::0000:0000:0000/96 ff30::ffff:ffff:ffff/96 RFC 3306 source-specific multicast
ff70::/12 ff7f:!/12 RFC 3956 embedded-RP multicast
ff40::/10 ffff:!/10 unassigned

Special interface numbers in anycast addresses.

IPv6 unicast/anycast interfaces
Suffix Notes
*:0000 Nearest router
*:fff7:ffff:ffff:ff80-ffff/57 Reserved anycast addresses (EUI-64)
*:fff7:ffff:ffff:fffe Mobile IPv6 home-agents (EUI-64)
*:ffff:ffff:ffff:ff80-ffff/57 Reserved anycast addresses (non EUI-64)
*:ffff:ffff:ffff:fffe Mobile IPv6 home-agents (non EUI-64)
fe80::c171:3a50 Nearest 6to4 gateway (

IPv6 multicast interfaces

Info from RFC 2375.

IPv6 multicast interfaces (group ids)
Suffix Notes
ff0?::0000 reserved
ff0?::0100 VMTP Managers Group
ff0?::0101 Network Time Protocol (NTP)
ff0?::0102 SGI-Dogfight
ff0?::0103 Rwhod
ff0?::0104 VNP
ff0?::0105 Artificial Horizons - Aviator
ff0?::0106 NSS - Name Service Server
ff0?::0107 AUDIONEWS - Audio News Multicast
ff0?::0108 SUN NIS+ Information Service
ff0?::0109 MTP Multicast Transport Protocol
ff0?::010A IETF-1-LOW-AUDIO
ff0?::010B IETF-1-AUDIO
ff0?::010C IETF-1-VIDEO
ff0?::010D IETF-2-LOW-AUDIO
ff0?::010E IETF-2-AUDIO
ff0?::010F IETF-2-VIDEO
ff0?::0110 MUSIC-SERVICE
ff0?::0112 SEANET-IMAGE
ff0?::0113 MLOADD
ff0?::0114 any private experiment
ff0?::0115 DVMRP on MOSPF
ff0?::0116 SVRLOC
ff0?::0117 XINGTV
ff0?::0118 microsoft-ds
ff0?::0119 nbc-pro
ff0?::011a nbc-pfn
ff0?::011b lmsc-calren-1
ff0?::011c lmsc-calren-2
ff0?::011d lmsc-calren-3
ff0?::011e lmsc-calren-4
ff0?::011f ampr-info
ff0?::0120 mtrace
ff0?::0121 RSVP-encap-1
ff0?::0122 RSVP-encap-2
ff0?::0123 SVRLOC-DA
ff0?::0124 rln-server
ff0?::0125 proshare-mc
ff0?::0126 dantz
ff0?::0127 cisco-rp-announce
ff0?::0128 cisco-rp-discovery
ff0?::0129 gatekeeper
ff0?::012a iberiagames
ff0?::0201 "rwho" Group (BSD) (unofficial)
ff0?::0002:0000-7ffd Multimedia Conference Calls
ff0?::0002:7ffe SAPv1 Announcements
ff0?::0002:7fff SAPv0 Announcements (deprecated)
ff0?::0002:8000-8fff SAP Dynamic Assignments
ff02::0001 all nodes
ff02::0002 all routers
ff02::0004 DVRMP routers
ff02::0005 OSPFUGP
ff02::0006 OSPFIGP designated routers
ff02::0007 ST routers
ff02::0008 ST hosts
ff02::0009 RIP routers
ff02::000a EIGRP routers
ff02::000b mobile agents
ff02::000d PIM routers
ff02::000e RSVP encapsulation
ff02::0001:0001 Link name
ff05::0002 all routers
ff05::0001:0003 all DHCP servers
ff05::0001:0004 all DHCP relays
ff05::0001:1000-13ff service location