Reserved IP addresses
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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. These IP addresses may be used for maintenance of routing tables, multicast, operation under failure modes, or to provide addressing space for public, unrestricted uses.
The IETF sets the guidelines for use of the IP address space in RFC specifications, and directs IANA to implement the policies. Reserved IP addresses tend to belong to three categories: addresses that are globally unique, addresses that are unique to the subnet, and addresses that are only relevant to the host using the address.[citation needed]
Reserved IPv4 addresses [edit]
| CIDR | Address Range | Number of Addresses | Routed on the public Internet | Purpose |
|---|---|---|---|---|
| 0.0.0.0/8 | 0.0.0.0 – 0.255.255.255 |
16777216 | No | Used for broadcast messages to the current ("this") network as specified by RFC 1700, page 4. |
| 10.0.0.0/8 | 10.0.0.0 – 10.255.255.255 |
16777216 | No | Used for local communications within a private network as specified by RFC 1918. |
| 100.64.0.0/10 | 100.64.0.0 – 100.127.255.255 |
4194304 | No | Used for communications between a Service Provider and its subscribers when using a Carrier-grade NAT, as specified by RFC 6598. |
| 127.0.0.0/8 | 127.0.0.0 – 127.255.255.255 |
16777216 | No | Used for loopback addresses to the local host, as specified by RFC 5735. |
| 169.254.0.0/16 | 169.254.0.0 – 169.254.255.255 |
65536 | No | Used for autoconfiguration 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, as specified by RFC 5735. |
| 172.16.0.0/12 | 172.16.0.0 – 172.31.255.255 |
1048576 | No | Used for local communications within a private network as specified by RFC 1918 |
| 192.0.0.0/29 | 192.0.0.0 – 192.0.0.7 |
8 | No | Used for the DS-Lite transition mechanism as specified by RFC 6333 |
| 192.0.2.0/24 | 192.0.2.0 – 192.0.2.255 |
256 | No | Assigned as "TEST-NET" in RFC 5737 for use solely in documentation and example source code and should not be used publicly. |
| 192.88.99.0/24 | 192.88.99.0 – 192.88.99.255 |
256 | Yes | Used by 6to4 anycast relays as specified by RFC 3068. |
| 192.168.0.0/16 | 192.168.0.0 – 192.168.255.255 |
65536 | No | Used for local communications within a private network as specified by RFC 1918. |
| 198.18.0.0/15 | 198.18.0.0 – 198.19.255.255 |
131072 | No | Used for testing of inter-network communications between two separate subnets as specified in RFC 2544. |
| 198.51.100.0/24 | 198.51.100.0 – 198.51.100.255 |
256 | No | Assigned as "TEST-NET-2" in RFC 5737 for use solely in documentation and example source code and should not be used publicly. |
| 203.0.113.0/24 | 203.0.113.0 – 203.0.113.255 |
256 | No | Assigned as "TEST-NET-3" in RFC 5737 for use solely in documentation and example source code and should not be used publicly. |
| 224.0.0.0/4 | 224.0.0.0 – 239.255.255.255 |
268435456 | Yes | Reserved for multicast assignments as specified in RFC 5771 |
| 240.0.0.0/4 | 240.0.0.0 – 255.255.255.254 |
268435455 | No | Reserved for future use, as specified by RFC 5735. |
| 255.255.255.255/32 | 255.255.255.255 | 1 | No | Reserved for the "limited broadcast" destination address, as specified by RFC 5735. |
Reserved IPv6 addresses [edit]
These addresses are listed in RFC 5156.
| CIDR | Address Range | Number of Addresses | Routed on the public Internet | Purpose |
|---|---|---|---|---|
| ::/128 | :: | 1 | No | Unspecified address |
| ::1/128 | ::1 | 1 | No | Used for loopback address to the local host. |
| ::ffff:0:0/96 | ::ffff:0.0.0.0 – ::ffff:255.255.255.255 |
232 | No | IPv4 mapped addresses |
| 64:ff9b::/96 | 64:ff9b::0.0.0.0 – 64:ff9b::255.255.255.255 |
232 | Yes[1] | IPv4/IPv6 translation (RFC 6052) |
| 2001::/32 | 2001:: – 2001::ffff:ffff:ffff:ffff:ffff:ffff |
296 | Yes | Teredo tunneling |
| 2001:10::/28 | 2001:10:: – 2001:1f:ffff:ffff:ffff:ffff:ffff:ffff |
2100 | No | Overlay Routable Cryptographic Hash Identifiers (ORCHID) |
| 2001:db8::/32 | 2001:db8:: – 2001:db8:ffff:ffff:ffff:ffff:ffff:ffff |
296 | No | Addresses used in documentation |
| 2002::/16 | 2002:: – 2002:ffff:ffff:ffff:ffff:ffff:ffff:ffff |
2112 | Yes | 6to4 |
| fc00::/7 | fc00:: – fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff |
2121 | No | Unique local address |
| fe80::/10 | fe80:: - febf:ffff:ffff:ffff:ffff:ffff:ffff:ffff |
2118 | No | Link-local address |
| ff00::/8 | ff00:: – ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff |
2120 | Yes | Multicast |
