subnet6 3ffe:501:ffff:100::/72
 {
  option dhcp6.name-servers 3ffe:501:ffff:100::1;
  range6 3ffe:501:ffff:100::10 3ffe:501:ffff:100::20;
  range6 3ffe:501:ffff:100::100 3ffe:501:ffff:100::200;
 }