A. Normally a DNS server holds records about various DNS zones which are replicated between other DNS servers (via the Active Directory in a AD enabled zone).

Caching-only DNS servers don't actually host any zones and are not authoritative for any domains but rather just cache results from queries asked them by clients. If a client asks it to resolve www.savilltech.com it will a zone holding DNS server to resolve it and cache the answer so if another client asks it to resolve the same record it can answer from its cache. This is similar in a way to a proxy server that caches popular web pages.

These are useful for sites connected via a WAN with a local caching-only DNS server saving on network traffic.

To configure a caching only DNS server perform the following:

  1. Ensure the machine has a static IP address
  2. Install the DNS service as per normal (Start - Settings - Control Panel - Add/Remove Software - Add/Remove Windows Components - Components - Networking Services - Details - Domain Name System (DNS) - OK - Next - Finish)
  3. Start the DNS MMC (Start - Programs - Administrative Tools - DNS)
  4. From the Action menu select 'Connect To Computer...'
  5. In the Select Target Computer window enable 'The following computer:' and enter the name of a DNS server you want to cache.
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  6. Click OK

The machine will now start to gather a cache of host-IP mappings.

To clear the cache right click on the actual server name (not the server it is caching from) and select 'Clear Cache' from the context menu.