if the preferred dns server is blank then the system takes dns as the host server and try to resolve the entries from its own cache if it is able to do it then finew other wise it will show dns error on the IE page.
same thing happens with the resources if its in the cache it will resolve the FQDN to IP othere wise will give error
What is the difference between a preferred DNS server and an altenate DNS server?Read more: http://wiki.answers.com/What_is_the_difference_between_a_preferred_DNS_server_and_an_altenate_DNS_server#ixzz2LRd3ICed
preferred dns: 68.87.64.146 alternate dns: 208.67.222.222 or 208.67.220.220
DNS spoofing
trick: go to local area connection and use d below mentioned dns server... Preferred DNS : 8.8.8.8 Alternate DNS : 8.8.4.4
authoritative dns server is server that has own databases that has name resolution for the clients that for resolve from name to ip address and for ip address to name. non-authorititative dns server is server that forward request of dns client to authoritative dns server for resolve.
Unbound - DNS Server - was created in 2007.
On a computer running a Windows operating system, you can find your DNS Server Address by clicking Start> Settings> Network connections. Then double click on Local Area Connection. Now click the properties button and select Internet protocol. Click on properties and find Preferred DNS Server.
The primary DNS server is usually the same as the router's IP adress.
If a DNS server cannot find the answer to the DNS Query in its own database it will first query the forwarders (if there are any configured) and then ask the root server. root servers (by default) are the master DNS servers of the Internet.
The prefered DNS server for the site is the server which sends the dns zone updates to all the other servers in the site. The primary DNS zone is created on the server and it has the authority to send changes in zone to other servers
referral
Domain Name System (DNS)