Secondary DNS gets its records from the Primary DNS Server. The secondary DNS is essentially there in case the primary DNS doesn't respond.
If a client send a query requesting for a particular web page to the DNS server and if the DNS server resolves the page from the other DNS servers & it will be store the same page in the DNS cache and it will give the response to the client with the requested page. If again the same web page is requested by any client then DNS server will get the web page from the DNS cache instead of again fetching the same page from the internet. With this there wont be any delay for the client to get the web page. This helps in bandwidth control. This is how the DNS server caching works.
ipconfig
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
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.
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
The DNS Server service in Windows Server® 2008 makes data retrieval faster by implementing background zone loading. In the past, enterprises with zones containing large numbers of records in Active Directory® experienced delays of up to an hour or more when the DNS Server service in Windows Server 2003 tried to retrieve the DNS data from Active Directory on restart. During these delays, the DNS server was unavailable to service DNS client requests for any of its hosted zones. To address this issue, the DNS Server service in Windows Server 2008 retrieves zone data from Active Directory in the background after it starts so that it can respond to requests for data from other zones. When the service starts, it creates one or more threads of execution to load the zones that are stored in Active Directory. Because there are separate threads for loading the Active Directory-based zones, the DNS Server service can respond to queries while zone loading is in progress. If a DNS client requests data in a zone that has already been loaded, the DNS server responds appropriately. If the request is for data in a zone that has not yet been entirely retrieved, the DNS server retrieves the specific data from Active Directory instead. This ability to retrieve specific data from Active Directory during zone loading provides an additional advantage over storing zone information in files-namely that the DNS Server service has the ability to respond to requests immediately. When the zone is stored in files, the service must sequentially read through the file until the data is found.
TCP/ IP protocol suite uses a DNS client. DNS stands for Domain name system .A DNS server maps a name to an address.