IPv6 — six types of unicast

IPv6 unicast has a one-to-one communication style. Every transmitter node on the network has a unique receiver node.

• ::1/128 corresponds to 127.0.0.0/8 in IPv4. Loopback is used to transmit packets back to the source of the packets without modifying them.
• FE80::/10 corresponds to 169.254.0.0/16 in IPv4. A link-local address is only valid for communication on a local network segment. Routers don’t forward packets with link-local addresses.
• Global unicast addresses are similar to IPv4 public addresses.
• IPv6 unspecified address is much like 0.0.0.0 in IPv4. This address is never assigned to a network device or as a destination address.
• Site-local address is similar to IPv4 private addresses. Routable only within a private network.
• IPv4 compatible addresses are assigned to devices that handle both IPv4 and IPv6 addresses.