DNS Cache Resolver overrides NS TTLs

[connah]

Hi all!

Would some please explain to me why Microsoft's DNS Cache Resolver has
it's own built in TTL defaulting to 86400 (24 hours) instead of paying
attention to the TTL that the domain's name server reports? This is
very frustrating to me. We set our TTLs on our domains in BIND to be
3600 (1 hour) so we can change our records and it get updated quickly.
However, Windows caches names for a day without regard to that setting.
It seems that since Windows being as ubiquitous as it is, the TTL
setting on an SOA record is meaningless.

I'm not just griping; I am truly hoping that I am wrong and someone
will set me straight. I would ultimately like to have control over how
long a client caches my domain's IP but it seems like Windows overrides
me. Thanks for any input!

Matthew

 

[Kevin D. Goodknecht Sr. [MVP]]

Hi all!

Would some please explain to me why Microsoft's DNS Cache Resolver has
it's own built in TTL defaulting to 86400 (24 hours) instead of paying
attention to the TTL that the domain's name server reports? This is
very frustrating to me. We set our TTLs on our domains in BIND to be
3600 (1 hour) so we can change our records and it get updated quickly.
However, Windows caches names for a day without regard to that
setting. It seems that since Windows being as ubiquitous as it is,
the TTL setting on an SOA record is meaningless.

I'm not just griping; I am truly hoping that I am wrong and someone
will set me straight. I would ultimately like to have control over how
long a client caches my domain's IP but it seems like Windows
overrides me. Thanks for any input!

MS DNS is not supposed to cache longer than the TTL of the record, there was
a problem in Win2k that was fixed with SP3.
BTW, without adding a machcachettl value to the registry, the maximum cache
time is 1 day.

DNS Server Caches NS Records Longer Than the TTL
http://support.microsoft.com/kb/303964/en-us

--
Best regards,
Kevin D. Goodknecht Sr. [MVP]
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[DK]

Hi all!

Would some please explain to me why Microsoft's DNS Cache Resolver has
it's own built in TTL defaulting to 86400 (24 hours) instead of paying
attention to the TTL that the domain's name server reports? This is
very frustrating to me. We set our TTLs on our domains in BIND to be
3600 (1 hour) so we can change our records and it get updated quickly.
However, Windows caches names for a day without regard to that setting.
It seems that since Windows being as ubiquitous as it is, the TTL
setting on an SOA record is meaningless.

I'm not just griping; I am truly hoping that I am wrong and someone
will set me straight. I would ultimately like to have control over how
long a client caches my domain's IP but it seems like Windows overrides
me. Thanks for any input!

Matthew

try ipconfig /flushdns