Unique Local Unicast Addresses
Unique local unicast addresses act as private IPv6 addresses. These addresses have many similarities with global unicast addresses, particularly in how to subnet. The biggest difference lies in the literal number (unique local addresses begin with hex FD), and with the administrative process: The unique local prefixes are not registered with any numbering authority, and can be used by multiple organizations.
Although the network engineer creates unique local addresses without any registration or assignment process, the addresses still need to follow some rules, as follows:
Use FD as the first two ...