New DNS Features in Windows Server 2008

 New DNS Features in Windows Server 2008

1.       DNS Server Role – DNS server service is now implemented as a Server Role using Server Manager. Which mean DNS is no longer installed via Add/Remove Windows Components.

2.       Background Zone Loading – Microsoft has changed the way DNS loads zone data from Active Directory. Sometimes the DNS server can take an hour or more to load the data with extremely large zone data. The result is that the DNS server is unable to serve the client’s requests for entire time it takes to load AD based zones.

A DNS server running Windows Server 2008 now loads zone data from AD in the back ground while it restarts so that it can respond to requests for data from other zones. Example – If you have 10 zones and data for first 3 zones data already loaded properly while it is loading other zone data, the DNS server can respond to the client’s request as expected for first 3 zones.

Because the task of loading zones is performed by separate threads, the DNS server is able to respond to queries while zone loading is in progress.

Another advantage of storing data in AD rather than in a file -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.

3.       Support for IPv6 – DNS Servers running on Windows Server 2008 now support IPv6 as fully as they support IPv4 addresses.  Which mean IPv6 support is available with DNS MMC as well as with tools. Example, IPv6 address can be displayed in Server Forwarder list or DNSCMD.exe tool accepts addresses in either format.

4.       Support for Read Only Domain Controllers (RODC) – To Support RODC, DNS server running Windows Server 2008 support a new zone type called the Primary Read-Only Zone.  When computer becomes RODC, it will get read only copy of all the application partitions that DNS uses. The Administrator of RODC can view contents of DNS but will unable to change it from RODC machine.

5.       GlobalNames Zone – Organization deploy WINS as secondary name resolution protocol along with DNS as they rely on global names which are unique & single-label. WINS requires NetBIOS over TCPIP and it do not support IPv6.

To assist organization to move to all-DNS environment, DNS server in Windows Server 2008 now supports a new zone called GlobalNames. Typically the replication scope for this zone is entire forest, which ensures that zone has the desired effect of providing unique, single-label names across forest.