Unique local addresses have 48-bit prefixes, leaving 16 bits for local subnetting. Below is the prefix as well as the addresses of the first and last subnets.
|Waiting to generate a ::/48
|Waiting to generate the 1st ::/64
|Waiting to generate the last ::/64
Not sure which subnet ID to use? Check the FAQ!
IPv6 unique local addresses (ULAs) are used similarly to the IPv4 local adresses, such 10.0.0.0/8. IPv4 private addresses were defined by RFC 1918, while IPv6 ULAs were defined by RFC 4193. Unlike their IPv4 counterpart, IPv6 local addresses have a 40-bit random part, which makes them unique. The goal of IPv6 local addresses is that if you connect two private IPv6 networks together - such as two private sites connected over VPN - it should be very unlikely that you will run into addressing conflicts. [+]