Caching Nameserver -- Windows client DNS/resolver default issue?

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Bryan J. Smith wrote:
 > Windows NT5+ (2000+) client systems have a _flawed_,
 > _default_ logic to "hold down" DNS resolution upon failure. That 
means if a DNS resolution fails, Windows clients will
 > _not_ requery the server _until_ that timeout passes.  There
 > is a registry hack to change this as follows:  [ From 
http://www.winguides.com/registry/display.php/1203/ ]
 >
 >   'To change the DNS cache timeout for negative responses
 >    (where a lookup failed).
 >    Windows 2000 - Create or modify the DWORD value called
 >    "NegativeCacheTime".
 >    Windows XP and .NET Server 2003 - Create or modify the
 >    DWORD value called "MaxNegativeCacheTtl".
 >    Set the value to equal the required timeout in seconds
 >    the default is 300 (5 minutes).
 >    Restart Windows for the changes to take effect.'
 >
 > It's my #1 recommendation until you resolve the problem.
 > UNIX clients/resolvers _never_ (AFAIK) cache a "failure,"
 > only Windows -- which I think is flawed, but there is a
 > reason for it (that has to do with legacy SMB file/print).
 >
 > Regardless of what solution you come to on the server,
 > consider doing the above.


Just to add to your knowledge base:

On Windows system, you can manually flush its dns cache, failed and 
otherwise, by opening a Command Window and typing:

ipconfig /flushdns


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