Hi @damianstelmach 

Thanks for posting in our business forum.

damianstelmach wrote

I wanted to force in router-level DOH support for the entire local network, but unfortunately without success. Previous actions:

1. Launching the DoH service on a router with two addresses (cloudflare and Quad4).

2. Unsuccessful blocking of port 53 on the router. Adding a BLOCK rule on port 53 for all directions and all IPs does not work.

Thank you for your help.

You cannot force DoH. DoH is an individual feature on each device that requires you to manually config on every single device.

The router can query the upstream DoH server but it does not DoH in the LAN. The LAN is still using UDP 53, plain text.

If you want DoH and secure DNS in LAN, configure each one of them manually with a DoH and that bypasses the router.

No such router can force DoH on its clients.