Request for ECS-like feature or extension to ECS

One of our support customers' product development team are investigating extending the functionality of their customer (presumably opt-in premium) content filtering service.

Currently the service works at the DNS layer by filtering that's aware of both the query source IP (public IP of the account) and the originally requested name.

The desired feature is to allow for different content filtering to be applied to different devices within the customer's home, i.e. on the other side of the NAT gateway.

This service provider has the ability to control the DNS proxying software on the SP-provided CPE, which in standard topologies will be able to identify individual devices based on their MAC address or LAN IP. Non-standard topologies where this is not possible are not a concern at this time.

BIND would not have to originate any of the device-identifying data, but it would have to be able to pass it along - though only to a specific set of servers for privacy reasons - and maintain a usable cache from the returned responses.