IPv6 - Unique Local addresses

A Unique Local address is an IPv6 address in the address range fc00::/7. It's purpose is analogous to the IPv4 Private IP address ranges.

These addresses can be freely used without centralized registration inside a single organization or spanning a number of sites or organizations. They are not routable on the global IPv6 Internet.

Unlike IPv4 private addresses, the purpose of IPv6 unique local addresses is to allow enterprises to use IPv6 address ranges without obligatorily registering IPv6 address ranges for use.