You goal is to configure hosts to automatically assign IPv6 addresses to themselves by the use of Router Advertisement messages, and also to obtain the DNS server address from a DHCPv6 server. Which address assignment method should be configured?

Stateless DHCPv6

Explanation:

We have three address assignment method possible:

Sateless Auto Address Configuration (SLAAC)

Stateless DHCPv6

Stateful DHCPv6

Stateful - Needs DHCPv6 server to get IP, DNS, etc.

Stateless - DHCPv6 server is not needed. In this mode, host get configuration (IP, DNS, etc.) from router address.

SLAAC is the simplest way to give an IPv6 address to a client, because it exclusively rely on Neighbor Discovery Protocol.

A Stateful address assignment involves someone keeping track of the State.

A Stateless address assignment does not keep track of what has or hasn't been assigned. In a Stateless assignment scenario, there is no server or device which keeps a running log of what IP addresses have been assigned and what IP addresses are remaining, available to be assigned.