If the WAN port is set to get the Ip from the ISP (Dynamic IP - DHCP)
And you set the DNS servers manually - 8.8.8.8 and 8.8.4.4
And under LAN you enable the DNX Proxy - the Router uses the DNS servers from the ISP to resolve Name Queries.
Try usuing this page:
To check you results.
If you disable the DNS Proxy then the DNS servers you entered in the WAN settings are forwarded to your PCs plus the ones from your ISP.