If under STATUS, DEVICE INFO on your DLINK router you see
Advanced DNS : Enabled
it means that your Router is going to ignore your internet providers DNS servers and go straight to OpenDNS’ DNS servers. OpenDNS has many positives but I have had performance problems with them in the past and twice given up on them. Advanced DNS / OpenDNS is also not useful if you are trying to test your system with your internet providers DNS.
You can clear the setting via SETUP > INTERNET SETUP > MANUAL INTERNET SETUP