Feature Request: Option for IP address preference and LAN IPv4/IPv6 for DoQ/DoT

[ericnixmd]

I have the vast majority of clients on my network configured with fixed/static IPs.

With the ctrld command line option client_id_preference, there is currently only available options for mac and host.

Please consider adding a lanip option as well.

Thanks!

[ericnixmd]

To further expand on this, I would also like to request that DoQ/DoT also report LAN IPv4/IPv6 addresses. I initially thought this wasn't possible, but this is possible with one of Control D's competitors using their relay server.

[andmar197264]

Draft comment

Thank you for opening and expanding this feature request — I would also like to express strong support for adding lanip as a client_id_preference option.

I have a similar environment where this feature would be very valuable in real-world use.

My network setup:
• MikroTik RB5009 router
• ctrld running in a Docker container (separate bridge subnet)
• Clients use DoH via ControlD through the router
• Most LAN devices are assigned stable or static IPv4 addresses

In this architecture, the router / ctrld instance appears as a single upstream resolver from ControlD’s perspective, so all DNS activity from the LAN is aggregated under one client identity.

For networks like this, mac and host identifiers are not always reliable because:
• MAC addresses may be hidden or rewritten (bridge networks, containers, VPN tunnels)
• hostnames are often missing, duplicated, or inconsistently provided by devices
• multiple logical clients collapse into a single resolver identity

However, LAN IPv4 addresses in these environments are:
• stable and deterministic
• intentionally assigned for policy control
• ideal for mapping filtering profiles per-device

Being able to identify clients by lanip would enable:
• individual policy profiles per LAN device
• clearer analytics and logging visibility
• isolation of misbehaving / noisy clients
• better troubleshooting in DoH-only setups
• safer segmentation without breaking resolver topology

This would especially help users running ctrld as a central policy resolver for entire LAN networks behind a router — which I believe is a fairly common deployment scenario.

I also support the extension for DoQ / DoT to forward LAN IPv4/IPv6 metadata where technically feasible (as mentioned above). This would make ControlD much more capable in structured LAN environments compared to competitors that already implement similar relay behavior.

Thank you for considering this — this feature would significantly improve usability for advanced router-based deployments.