The use of a DHCPv6 server is optional for IPv6. In principle, a DHCPv6 server supports two modes:
- Stateless: The DHCPv6 server does not distribute addresses but only information, such as DNS server addresses. Using this method, clients generate their own IPv6 addresses by 'stateless address auto-configuration (SLAAC)'. This method is particularly attractive for example for small networks in order to keep administration efforts to a minimum.
- Stateful: The DHCPv6 server distributes IPv6 addresses, similar to IPv4. This method is more complicated, since a DHCPv6 server has to assign and manage the addresses.
A DHCPv6 server distributes only the options that are explicitly requested by an IPv6 client, i. e. the server only assigns an address to a client if it explicitly requests one.
Additionally, the DHCPv6 server can pass on prefixes to routers for further distribution. This method is referred to as 'prefix delegation'. A DHCPv6 client must have explicitly requested this prefix, however.