Reserved IP addresses

In the Internet addressing architecture, the Internet Engineering Task Force (IETF) and the Internet Assigned Numbers Authority (IANA) have reserved various Internet Protocol (IP) addresses for special purposes.[1]

## IPv4

[edit]

This section is transcluded from IPv4#Special-use addresses. (edit | history)

IPv4 designates special usage or applications for various addresses or address blocks:[1][2]

Special address blocks  Address block  | Address range  | Number of addresses  | Scope  | Description

|
|
|
|

0.0.0.0/8  | 0.0.0.0–0.255.255.255  | 16777216 | Software  | Current (local, "this") network[1]
10.0.0.0/8  | 10.0.0.0–10.255.255.255  | 16777216 | Private network  | Used for local communications within a private network[3]
100.64.0.0/10  | 100.64.0.0–100.127.255.255  | 4194304 | Private network  | Shared address space[4] for communications between a service provider and its subscribers when using a carrier-grade NAT
127.0.0.0/8  | 127.0.0.0–127.255.255.255  | 16777216 | Host  | Used for loopback addresses to the local host[1]
169.254.0.0/16  | 169.254.0.0–169.254.255.255  | 65536 | Subnet  | Used for link-local addresses[5] between two hosts on a single link when no IP address is otherwise specified, such as would have normally been retrieved from a DHCP server
172.16.0.0/12  | 172.16.0.0–172.31.255.255  | 1048576 | Private network  | Used for local communications within a private network[3]
192.0.0.0/24  | 192.0.0.0–192.0.0.255  | 256 | Private network  | IETF Protocol Assignments, DS-Lite (/29)[1]
192.0.2.0/24  | 192.0.2.0–192.0.2.255  | 256 | Documentation  | Assigned as TEST-NET-1, documentation and examples[6]
192.88.99.0/24  | 192.88.99.0–192.88.99.255  | 256 | Internet  | Reserved.[7] Formerly used for IPv6 to IPv4 relay[8] (included IPv6 address block 2002::/16).
192.168.0.0/16  | 192.168.0.0–192.168.255.255  | 65536 | Private network  | Used for local communications within a private network[3]
198.18.0.0/15  | 198.18.0.0–198.19.255.255  | 131072 | Private network  | Used for benchmark testing of inter-network communications between two separate subnets[9]
198.51.100.0/24  | 198.51.100.0–198.51.100.255  | 256 | Documentation  | Assigned as TEST-NET-2, documentation and examples[6]
203.0.113.0/24  | 203.0.113.0–203.0.113.255  | 256 | Documentation  | Assigned as TEST-NET-3, documentation and examples[6]
224.0.0.0/4  | 224.0.0.0–239.255.255.255  | 268435456 | Internet  | In use for multicast[10] (former Class D network)
233.252.0.0/24  | 233.252.0.0–233.252.0.255  | 256 | Documentation  | Assigned as MCAST-TEST-NET, documentation and examples (This is part of the above multicast space.)[10][11]
240.0.0.0/4  | 240.0.0.0–255.255.255.254  | 268435455 | Internet  | Reserved for future use[12] (former Class E network)
255.255.255.255/32  | 255.255.255.255  | 1 | Subnet  | Reserved for the "limited broadcast" destination address[1]

## IPv6

[edit]

This section is transcluded from IPv6 address#Special addresses. (edit | history)

IPv6 assigns special uses or applications for various IP addresses:[1]

Special address blocks  Address block (CIDR)  | First address  | Last address  | Number of addresses  | Usage  | Purpose

|
|
|
|
|

::/128  | ::  | ::  | 1  | Software  | Unspecified address
::1/128  | ::1  | ::1  | 1  | Host  | Loopback address—a virtual interface that loops all traffic back to itself, the local host
::ffff:0:0/96  | ::ffff:0.0.0.0 ::ffff:0:0  | ::ffff:255.255.255.255 ::ffff:ffff:ffff  | 232 | Software  | IPv4-mapped addresses
::ffff:0:0:0/96  | ::ffff:0:0.0.0.0 ::ffff:0:0:0  | ::ffff:0:255.255.255.255 ::ffff:0:ffff:ffff  | 232 | Software  | IPv4-translated addresses
64:ff9b::/96  | 64:ff9b::0.0.0.0 64:ff9b::0:0  | 64:ff9b::255.255.255.255 64:ff9b::ffff:ffff  | 232 | The global Internet  | IPv4/IPv6 translation[13]
64:ff9b:1::/48  | 64:ff9b:1::  | 64:ff9b:1:ffff:ffff:ffff:ffff:ffff  | 280, with 248 for each IPv4  | Private internets  | IPv4/IPv6 translation[14]
100::/64  | 100::  | 100::ffff:ffff:ffff:ffff  | 264 | Routing  | Discard prefix[15]
2001::/32  | 2001::  | 2001:0:ffff:ffff:ffff:ffff:ffff:ffff  | 296 | The global Internet  | Teredo tunneling[16]
2001:20::/28  | 2001:20::  | 2001:2f:ffff:ffff:ffff:ffff:ffff:ffff  | 2100 | Software  | ORCHIDv2[17]
2001:db8::/32  | 2001:db8::  | 2001:db8:ffff:ffff:ffff:ffff:ffff:ffff  | 296 | Documentation  | Addresses used in documentation and example source code[18]
2002::/16  | 2002::  | 2002:ffff:ffff:ffff:ffff:ffff:ffff:ffff  | 2112 | The global Internet  | The 6to4 addressing scheme
3fff::/20  | 3fff::  | 3fff:fff:ffff:ffff:ffff:ffff:ffff:ffff  | 2108 | Documentation  | Addresses used in documentation and example source code[19]
5f00::/16  | 5f00::  | 5f00:ffff:ffff:ffff:ffff:ffff:ffff:ffff  | 2112 | Routing  | IPv6 Segment Routing (SRv6)[20]
fc00::/7  | fc00::  | fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff  | 2121 | Private internets  | Unique local address[21]
fe80::/64 from fe80::/10  | fe80::  | fe80::ffff:ffff:ffff:ffff  | 264 | Link  | Link-local address
ff00::/8  | ff00::  | ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff  | 2120 | The global Internet  | Multicast address

## See also

[edit]

* Bogon filtering
* Martian packet
* Classless Inter-Domain Routing (CIDR)
* Top-level domain § Reserved domains

## References

[edit]

1. ^ a b c d e f g M. Cotton; L. Vegoda; B. Haberman (April 2013). R. Bonica (ed.). Special-Purpose IP Address Registries. Internet Engineering Task Force. doi:10.17487/RFC6890. ISSN 2070-1721. BCP 153. RFC 6890. Best Current Practice 153. Obsoletes RFC 4773, 5156, 5735 and 5736. Updated by RFC 8190.
2. ^ "IANA IPv4 Special-Purpose Address Registry". IANA. 19 August 2009.
3. ^ a b c Y. Rekhter; B. Moskowitz; D. Karrenberg; G. J. de Groot; E. Lear (February 1996). Address Allocation for Private Internets. Network Working Group. doi:10.17487/RFC1918. BCP 5. RFC 1918. Best Current Practice 5. Obsoletes RFC 1627 and 1597. Updated by RFC 6761.
4. ^ J. Weil; V. Kuarsingh; C. Donley; C. Liljenstolpe; M. Azinger (April 2012). IANA-Reserved IPv4 Prefix for Shared Address Space. Internet Engineering Task Force. doi:10.17487/RFC6598. ISSN 2070-1721. BCP 153. RFC 6598. Best Current Practice 153. Updates RFC 5735.
5. ^ S. Cheshire; B. Aboba; E. Guttman (May 2005). Dynamic Configuration of IPv4 Link-Local Addresses. Network Working Group. doi:10.17487/RFC3927. RFC 3927. Proposed Standard.
6. ^ a b c J. Arkko; M. Cotton; L. Vegoda (January 2010). IPv4 Address Blocks Reserved for Documentation. Internet Engineering Task Force. doi:10.17487/RFC5737. ISSN 2070-1721. RFC 5737. Informational. Updates RFC 1166.
7. ^ O. Troan (May 2015). B. Carpenter (ed.). Deprecating the Anycast Prefix for 6to4 Relay Routers. Internet Engineering Task Force. doi:10.17487/RFC7526. BCP 196. RFC 7526. Best Current Practice 196. Obsoletes RFC 3068 and 6732.
8. ^ C. Huitema (June 2001). An Anycast Prefix for 6to4 Relay Routers. Network Working Group. doi:10.17487/RFC3068. RFC 3068. Informational. Obsoleted by RFC 7526.
9. ^ S. Bradner; J. McQuaid (March 1999). Benchmarking Methodology for Network Interconnect Devices. Network Working Group. doi:10.17487/RFC2544. RFC 2544. Informational. Updated by: RFC 6201 and RFC 6815.
10. ^ a b M. Cotton; L. Vegoda; D. Meyer (March 2010). IANA Guidelines for IPv4 Multicast Address Assignments. IETF. doi:10.17487/RFC5771. ISSN 2070-1721. BCP 51. RFC 5771. Best Current Practice 51. Obsoletes RFC 3138 and 3171. Updates RFC 2780.
11. ^ S. Venaas; R. Parekh; G. Van de Velde; T. Chown; M. Eubanks (August 2012). Multicast Addresses for Documentation. Internet Engineering Task Force. doi:10.17487/RFC6676. ISSN 2070-1721. RFC 6676. Informational.
12. ^ J. Reynolds, ed. (January 2002). Assigned Numbers: RFC 1700 is Replaced by an On-line Database. Network Working Group. doi:10.17487/RFC3232. RFC 3232. Informational. Obsoletes RFC 1700.
13. ^ C. Bao; C. Huitema; M. Bagnulo; M. Boucadair; X. Li (October 2010). IPv6 Addressing of IPv4/IPv6 Translators. Internet Engineering Task Force (IETF). doi:10.17487/RFC6052. ISSN 2070-1721. RFC 6052. Proposed Standard. Updates RFC 4291.
14. ^ T. Anderson (August 2017). Local-Use IPv4/IPv6 Translation Prefix. Internet Engineering Task Force. doi:10.17487/RFC8215. RFC 8215. Proposed Standard.
15. ^ N. Hilliard; D. Freedman (August 2012). A Discard Prefix for IPv6. Internet Engineering Task Force. doi:10.17487/RFC6666. ISSN 2070-1721. RFC 6666. Informational.
16. ^ S. Santesson (September 2006). TLS Handshake Message for Supplemental Data. Network Working Group. doi:10.17487/RFC4680. RFC 4680. Proposed Standard. Updates RFC 4346. Updated by RFC 8447 and 8996.
17. ^ J. Laganier; F. Dupont (September 2014). An IPv6 Prefix for Overlay Routable Cryptographic Hash Identifiers Version 2 (ORCHIDv2). Internet Engineering Task Force. doi:10.17487/RFC7343. ISSN 2070-1721. RFC 7343. Proposed Standard. Obsoletes RFC 4843.
18. ^ G. Huston; A. Lord; P. Smith (July 2004). IPv6 Address Prefix Reserved for Documentation. Network Working Group. doi:10.17487/RFC3849. RFC 3849. Informational. Updated by RFC 9637.
19. ^ G. Huston; N. Buraglio (August 2024). Expanding the IPv6 Documentation Space. Internet Engineering Task Force. doi:10.17487/RFC9637. RFC 9637. Informational. Updates RFC 3849.
20. ^ S. Krishnan (October 2024). Segment Routing over IPv6 (SRv6) Segment Identifiers in the IPv6 Addressing Architecture. Internet Engineering Task Force. doi:10.17487/RFC9602. RFC 9602. Informational.
21. ^ R. Hinden; B. Haberman (October 2005). Unique Local IPv6 Unicast Addresses. Network Working Group. doi:10.17487/RFC4193. RFC 4193. Proposed Standard.

## External links

[edit]

* IANA IPv4 Special-Purpose Address Registry
* IANA IPv6 Special-Purpose Address Registry