Unicast addresses represent a single interface. Packets addressed to a unicast address will be delivered to a specific network interface.
There are three types of IPv6 unicast addresses:
- global unicast – similar to IPv4 public IP addresses. These addresses are assigned by the IANA and used on public networks. They have a prefix of 2000::/3, (all the addresses that begin with binary 001).
- unique local – similar to IPv4 private addresses. They are used in private networks and aren’t routable on the Internet. These addresses have a prefix of FD00::/8.
- link local – these addresses are used for sending packets over the local subnet. Routers do not forward packets with this addresses to other subnets. IPv6 requires a link-local address to be assigned to every network interface on which the IPv6 protocol is enabled. These addresses have a prefix of FE80::/10.
Let’s describe each of the IPv6 unicast address type in more detail.