The prefix length (e.g. the "/64" in above examples) must always be specified.
Disable/Enable stateless IPv6 auto configuration.
With stateless address auto configuration, a device interface is automatically assigned a link-local IPv6 address by the system. This link-local IPv6 address is generated with a fixed local address prefix (fe80::) to a token derived from the MAC address. (The address is verified to be unique.) This allows each IPv6 interface to have at least one source address that can be used by Neighbor Discovery. If an IPv6 router on the network advertises network prefixes in router advertisements, IPv6 derives IPv6 addresses based on the network interface identifier of the interface and on the network prefixes advertised.
There are 4 addresses left for further configurations by using the Neighbour discovery protocol.
By default stateless auto configuration is enabled.