This configuration is for a Western Digital MyNet N750 and N900; however, it should be similar to other models.
Original Manual: http://www.wdc.com/wdproducts/library/UM/ENG/4779-705074.pdf
Step 1: Log into your router using either the Setup CD provided with the router or type the following IP address or URL into your browsers address bar.
2. Select Advanced Settings, then go to WAN -> Internet Setup
Enter 208.67.220.220 and 208.67.222.222 as the Primary and Secondary DNS Server, then click Save.
3. Under LAN-> Host and LAN settings, ensure that the DNS Proxy and/or DNS Relay is turned OFF.
4. Cache Flushing
Once you have configured your DNS settings and clicked the Submit button, we highly suggest that you flush your DNS resolver cache and web browser caches to ensure that your new DNS configuration settings take immediate effect.