dhcpd.conf

subnet6 2001:db8::/32 {
        range6 2001:db8:0:1::129 2001:db8:0:1::254;

        # Range for clients requesting a temporary address
        range6 2001:db8:0:1::/64 temporary;

        # Additional options
        option dhcp6.name-servers fec0:0:0:1::1;
        option dhcp6.domain-search "domain.example";

        # Prefix range for delegation to sub-routers
        prefix6 2001:db8:0:100:: 2001:db8:0:f00:: /56;
        on commit {
                if exists dhcp6.ia-na and exists dhcp6.ia-pd {
                        set route-pdexists = "yes";
                        set route-iana = binary-to-ascii(16,16,":",substring(suffix(option dhcp6.ia-na,24),0,16));
                        set route-iapd = binary-to-ascii(16,16,":", suffix(option dhcp6.ia-pd,16));
                        set route-pdsize = binary-to-ascii(10,8,":",substring(suffix(option dhcp6.ia-pd,17),0,1));
                        set route-pdnet = concat(route-iapd, "/", route-pdsize);
                        execute("/sbin/ip", "-6", "route", "add", route-pdnet, "via", route-iana);
                }
        }
        on release {
                if route-pdexists = "yes" {
                        execute("/sbin/ip", "-6", "route", "delete", route-pdnet, "via", route-iana);
                }
        }
}