Date: 2017jan31 Product: D-Link DIR-655 Q. My DHCP users have occasional DNS lookup problems, how can I fix this? A. I found a solution for my DIR-655. It was giving its address as the DNS server to DHCP clients. This is the DNS Relay option. When its disabled:

Setup > Network Settings [ ] Enable DNS Relay

It gives the DNS servers that it uses to clients. That removes the middle man and it works better.