Best practices for client-specific DNS filtering with IPv6 enabled

[cinergi2]

Hello,

I'm wondering how best to implement DNS filtering for specific clients when IPv6 is enabled? With IPv4, it's fairly straightforward to assign a fixed IP via DHCP reservation, and filter based on the IP. With IPv6 and SLAAC, however, IPv6 addresses assigned to clients are unpredictable. I could disable SLAAC and only use DHCPv6 with reservations, but then any devices that don't support DHCPv6 won't get an IPv6 address (notably all Android and Chrome OS devices), so I would need to segment those on a separate VLAN (which seems like overkill). It's also not possible to block based on the MAC address for some reason unless Adguard is acting as the network DHCP server (which is not the case for me), although Pihole (for example) supports it. So what to do?

Thank you.