Quick Intro to IPv6 Address Formatting
This table gives the major forms of IPv6 addresses. The most important/common are Localhost (::1), Global Unicast (usually starting with "200x"), and Link-Local Unicast (starting with "FF80").
| Address Type | Binary Prefix | IPv6 Notation |
|---|---|---|
| Unspecified | 00...0 (128 bits) | ::/128 |
| Loopback | 00...1 (128 bits) | ::1/128 |
| Multicast | 1111 1111 | FF00::/8 |
| Link-Local Unicast | 1111 1110 10 | FE80::/10 |
| ULA (*) | 1111 110 | FC00::/7 |
| Global Unicast (**) | 001 | 2000::/3 |
| IPv4-Mapped | 00...0:1111 1111:IPv4 | ::FFFF:IPv4/128 |
| Site-Local Unicast (***) | 1111 1110 11 | FECO::/10 |
| IPv4-compatible (***) | 00...0 (96 bits) | ::IPv4/128 |
* Unique Local Address (ULA) is an IPv6 unicast address that is generated to be unique in a local context. It is highly likely to be unique globally.
** Global Unicast address are all currently being assigned with a 2000::/3 prefix. Other three-bit prefixes are reserved for future use.
*** Site-Local Unicast and IPv4-compatible prefixes are deprecated. Use ULA and IPv4-mapped addresses, respectively.