Windows Server which is running Active Directory will have its own DNS
server running. For typical setup, this DNS server will listen on all
interfaces, and receiving queries from others to be able to resolve
computer name in domain.
That would make ctrld default setup never works, since ctrld can listen
on port 53, but requests are never be routed to its listeners.
To integrate ctrld in this case, we need to listen on a local IP
address, then configure this IP as a Forwarder of local DNS server. With
this setup, computer name on domain can still be resolved, and other
queries can still be resolved by ctrld upstream as usual.
