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 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

node local: unspecified address

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

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

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 (193.113.58.80)

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 (193.113.58.80)

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?::0111`	SEANET-TELEMETRY
`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?::0202`	SUN RPC PMAPPROC_CALLIT
`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