I have a GL-AR750 I use as a secondary internet connection, I need to completely disable DHCP on the device to let my real server deliver DHCP.
I also had a problem where if I set custom DNS in the router, the router still gives its self as DNS to the clients. However watching the logs, the router is using my custom DNS as its querying server. So why can’t it go ahead and pass the address to the client and let the client contact the DNS directly.
To get around this I have had to configure DNS on most devices to communicate directly to the DNS, and not around about through the router.