Unique Local//
IPv6 unique local addresses are similar to private IPv4 addresses. These addresses can be used by companies that do not plan to connect to the Internet, and companies that plan to use IPv6 Network Address Translation (NAT).
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These addresses are readily available, and you can simply read documentation and start assigning IPv6 addresses without worrying about registration with IANA or another authority. Multiple companies can possibly end up using the exact same IPv6 unique local addresses, and it works just fine just like private IPv4 addresses.