IPv6 address/prefix allocation sequence
The DHCPv6 server selects an IPv6 address/prefix for a client in the following sequence:
IPv6 address/prefix statically bound to the client's DUID and IAID and expected by the client.
IPv6 address/prefix statically bound to the client's DUID and IAID.
IPv6 address/prefix statically bound to the client's DUID and expected by the client.
IPv6 address/prefix statically bound to the client's DUID.
IPv6 address/prefix that was ever assigned to the client.
Assignable IPv6 address/prefix in the address pool/prefix pool expected by the client.
Assignable IPv6 address/prefix in the address pool/prefix pool.
IPv6 address/prefix that was a conflict or passed its lease duration. If no IPv6 address/prefix is assignable, the server does not respond.
If a client moves to another subnet, the DHCPv6 server selects an IPv6 address/prefix from the address pool that matches the new subnet.
Conflicted IPv6 addresses can be assigned to other DHCPv6 clients only after the addresses are in conflict for one hour.