With IPv6, each address on each interface has a flag associated with the IP address, detailing how it was assigned and whether it should be used.
|permanent||This address was configured manually (default)|
|dynamic||Thie address was learnt through RouterAdvertisement?|
|secondary||This address is not used when selecting a source address of a new IPv6 packet.|
|primary||This address is used when selecting a source address of a new IPv6 packet.|
|tentative||This address was added to an interface, but it's not yet clear if it's unique on this network segment, so the address is not used (yet).|
|deprecated||This address has expired and will not be used for further outgoing connections (but will still be around in case of connections that are still using this address)|