IPv6 configuration with RDNSS (RFC 6106)

DCLTechnique

Hello,

We are MSP which deployed IPv6 internally on one of client's existing Zyxel firewall. The device in question is an USG Flex 200 running firmware 5.40 (latest). Coming from Fortinet / FortiOS we find the IPv6 configuration on Zyxel convoluted as there is no official knowledge base (aside from random official blog posts linking to PDFs)

We have got he following configuration enabled :

• One /64 assigned to the WAN interface, the Zyxel obtains a SLAAC adresse from that prefixe
• One /56 routed on the the WAN's /64, of which two /64 are assigned on LAN1 and LAN2 interfaces
• DHCP-PD is enabled to assign AAAA:BBBB:CCCC:DDD1::/64 and
• AAAA:BBBB:CCCC:DDD2::/64 to the LANs

SLAAC is enabled on both LANs and Windows machines get IPv6 connectivity. However this requires using stateless DHCPv6 which is not supported on Android-based devices, meaning that our devices do get an address but no DNS servers

Where can we configure IPv6 RDNSS (RFC 6106) in order to transmit DNS servers through Router Advertisements ? I cannot find this anywhere on any public documentation nor any CLI reference

Thank you