Special purpose addresses

The table below contains special purpose addresses. These are addresses you either cannot use legitimately, or are reserved in ways that you will never encounter them on the internet (but may in a private network). The country code "__" as well as ASN "0" contain them among other addresses

CIDR Low address High address Address count Type Description
0.0.0.0/8 0.0.0.0 0.255.255.255 16'777'216 Special Addresses in this range refer to the local network. If your local address and network is 192.168.1.10/24, 0.0.0.5 would refer to 192.168.1.5. Support for this is not universal, except for 0.0.0.0, which depending on the context means 'any address' or 'no address'
10.0.0.0/8 10.0.0.0 10.255.255.255 16'777'216 PrivateUse Largest address block to use for local networks
100.64.0.0/10 100.64.0.0 100.127.255.255 4'194'304 PrivateUse Carrier grade NAT range. This range can be used by network providers to hide multiple subscribers behind the same public IP address if not enough public addresses are available.
127.0.0.0/8 127.0.0.0 127.255.255.255 16'777'216 Loopback All 16 million addresses in this range point to the local machine. 127.0.0.1 is the most commonly used one
169.254.0.0/16 169.254.0.0 169.254.255.255 65'536 Special Address automatically assigned by the operating system if no address is configured or obtainable (for example via DHCP). Not widely used in production, and usually indicates a network misconfiguration
172.16.0.0/12 172.16.0.0 172.31.255.255 1'048'576 PrivateUse Medium address block to use for local networks. Behaves like 10.0.0.0/8 but is smaller
192.0.0.0/24 192.0.0.0 192.0.0.255 256 Reserved Reserved for special purposes. Sometimes used to encapsulate IPv4 inside of IPv6
192.0.2.0/24 192.0.2.0 192.0.2.255 256 Documentation Reserved for documentation and testing purposes
192.88.99.0/24 192.88.99.0 192.88.99.255 256 Reserved Used as an IPv6 transition mechanism
192.168.0.0/16 192.168.0.0 192.168.255.255 65'536 PrivateUse Small address block to use for local networks. Behaves like 10.0.0.0/8 but is the smallest block available. Often used for home networks
198.18.0.0/15 198.18.0.0 198.19.255.255 131'072 PrivateUse Used for benchmarks (RFC 2544)
198.51.100.0/24 198.51.100.0 198.51.100.255 256 Documentation Reserved for documentation and testing purposes
203.0.113.0/24 203.0.113.0 203.0.113.255 256 Documentation Reserved for documentation and testing purposes
224.0.0.0/4 224.0.0.0 239.255.255.255 268'435'456 Special Multicast communication (sending a single packet to multiple peers at once)
233.252.0.0/24 233.252.0.0 233.252.0.255 256 Documentation Reserved for documentation and testing purposes, but fully usable because it's entirely contained in the multicast address range
240.0.0.0/4 240.0.0.0 255.255.255.255 268'435'456 Reserved Reserved for future use
255.255.255.255/32 255.255.255.255 255.255.255.255 1 Special Broadcast address. Packets sent to this address are forwarded to all hosts in the same subnet. The highest address in every network block also serves this purpose and could be used
::/128 :: :: 1 Special Like 0.0.0.0, depending on the context means 'any address' or 'no address'
::1/128 ::1 ::1 1 Loopback Loopback address. Unlike IPv4, only one address exists
::FFFF:0:0/96 ::FFFF:0:0 ::FFFF:255.255.255.255 4'294'967'296 Special Range to 1:1 map an IPv4 address into. It's often written as a mix of IPv6 (hex with colon separator) and IPv4 (decimal with dot separator), for example the address 198.51.100.7 would be written as ::FFFF:198.51.100.7. The entire IPv4 address fits into the two last hexadecimal blocks of the IPv6 range. This translation method is commonly used by the operating system if software wants to accept IPv4 and IPv6 connections on the same listener socket
64:FF9B::/96 64:FF9B:: 64:FF9B::FFFF:FFFF 4'294'967'296 Special Range to 1:1 map an IPv4 address into. Unlike ::ffff:0:0/96, this range is for manual mapping via a NAT mechanism
64:FF9B:1::/48 64:FF9B:1:: 64:FF9B:1:FFFF:FFFF:FFFF:FFFF:FFFF 1.21×1024 Special Range to map IPv4 addresses into. This range is for manual mapping via a NAT mechanism. Being larger than necessary, multiple IPv6 address can map to the same IPv4 address
100::/64 100:: 100::FFFF:FFFF:FFFF:FFFF 1.84×1019 Special Packets sent to this address are discarded (RFC 6666)
2001::/32 2001:: 2001:0:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 7.92×1028 Special Teredo tunneling. A Microsoft transition protocol that can work from behind an IPv4 NAT
2001:2::/48 2001:2:: 2001:2:0:FFFF:FFFF:FFFF:FFFF:FFFF 1.21×1024 PrivateUse Used for benchmarks. The IPv6 variant of 198.18.0.0/15
2001:20::/28 2001:20:: 2001:2F:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 1.27×1030 Special Overlay Routable Cryptographic Hash Identifiers Version 2 (RFC 7343) These are non-routed IPv6 addresses used for cryptographic hashes
2001:DB8::/32 2001:DB8:: 2001:DB8:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 7.92×1028 Documentation Reserved for documentation and testing purposes
2002::/16 2002:: 2002:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 5.19×1033 Special Special purpose addresses to route IPv6 over IPv4
3FFF::/20 3FFF:: 3FFF:FFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 3.25×1032 Documentation Reserved for documentation and testing purposes
5F00::/16 5F00:: 5F00:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 5.19×1033 Special Segment routing. Allows packets to contain routing information
FC00::/7 FC00:: FDFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 2.66×1036 PrivateUse Unique local address. This is the IPv6 variant of 10.0.0.0/8
FE80::/10 FE80:: FEBF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 3.32×1035 PrivateUse Link-local address (automatically and randomly assigned by the operating system)
FE80::/64 FE80:: FE80::FFFF:FFFF:FFFF:FFFF 1.84×1019 PrivateUse Link-local address. This is fully contained within FE80::/10, and all operating systems assign from this smaller range only as of now.
FF00::/8 FF00:: FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF 1.33×1036 Special Multicast communication (sending a single packet to multiple peers at once)