LAN DNS lookup? Where are your LAN DNS records stored? Internet DNS lookup will be routed directly thru most D-Link routers when DNS relay is enabled. You will need to adjust so as to add your own DNS server onto the LAN or fix your "host" file entries.
DNS resolution will go thru the list of DNS servers first and then go to any host file entries. Therefore, if your have DNS server entries, it will sequentially check the Primary, Secondary and "other" server IP addresses before your host files.