How can I change or specify DNS Cache Timings on Windows 2003 Server?
Posted on 2008-11-19
I'm trying to configure a monitor to check that a website is resolvable to its IP address. We recent had a DNS failure with our ISP and our external web sites could not be reached. I have the monitor in place and it seems to work but the concern is that DNS will cache the result and report positive even when the URL is no longer resolvable.
What i need to be able to do is limit the length of time a DNS resolution is valid in the cache, effectively forcing a recheck. I have had a look at DNS itself but there is little to configure. I found the following for DNS clients, but it is unclear what impact this would have if applied to a 2003 server:-
"Tuning DNS Caching under Microsoft Windows
You can modify the behaviour of the Microsoft Windows DNS caching algorithm by setting two registry entries in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters registry key.
The MaxCacheTtl represents the maximum time that the results of a DNS lookup will be cached. The default value is 86,400 seconds. If you set this value to 1, DNS entries will only be cashed for a single second.
MaxNegativeCacheTtl represents the maximum time that the results of a failed DNS lookup will be cached. The default value is 900 seconds. If you set this value to 0, failed DNS lookups will not be cached."
Thanks in advance,