I have my Archer AXE300 set up behind my BGW321-500 via IP Passthrough, using the instructions here.  

DNS appears to be resolving external domains, but not resolving internal domains.  I have read that others have had to set up their own personal DNS servers to get around this limitation, which is imposed by the BGW321-500 not allowing bridge mode.

Can the Archer AXE300 force specific devices on my network to use specific nameservers (DNS). Either globally, or on a per device basis, so that i can set up my own DNS Server?

Or, is there another way to resolve my issue in such a way that I can get internal DNS resolution working?