PLANET WGSW-52040 - Manual (Page 272)

router responsible for DHCPv6 packet forwarding has DHCPv6 relay function. If
DHCPv6 relay is not available for the intermediate router, it is recommended to
replace the router or upgrade its software to one that has a DHCPv6 relay function;
 Sometimes hosts are connected to the DHCPv6 enabled switches, but can not get
IPv6 addresses. In this situation, it should be checked first whether the ports which
the hosts are connected to, are connected with the port which the DHCPv6 server is
connected to. If connected directly, it should be checked then whether the IPv6
address pool of the VLAN which the port belongs to, is in the same subnet with the
address pool configure in the DHCPv6 server; If not connected directly, and any
layer three DHCPv6 relay is configured between the hosts and the DHCPv6 server, it
should be checked first whether an valid IPv6 address has been configured for the
switch interface which the hosts are connected to. If not configured, configure an
valid IPv6 address. If configured, it should be checked whether the configured IPv6
address is in the same subnet with the DHCPv6 server. If not, please add it to the
address pool.
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