DNS Cache Problems?

[Andrew Harlan]

I have sporadic problems reaching sites especially a
particular one. Once I clear the DNS cache I am able to
borse and access email on our workstations and DNS
server. The thing is, is that when this happens and I
look at the cache under the domain organizations which I
am trying to reach, there are no records for the address
to an IP. For example when trying to reach
mail.domain.org, when I look inside the cahce for
org\domain only the name servers are listed an not hte
mail record corresponding to an IP. This happens in
particular for are ISP mail server but I have also caught
it happening to msn.com and other common addresses.
I have enabled pollution control in DNS properties and
have turned off forwarders to our router This happens
about once every two or three weeks for two days in a row
and then goes away. It is quite a mystery. I would
appreciate any insight anyone may have. Thanks.

 

[Steve Duff [MVP]]

From time to time people here report this sort
of cache corruption in Win2K DNS Server after
it has been running for some time, causing random
domains to become effectively unreachable -- presumably
because of some sort of errant negative response
caching. I've seen it myself more than a couple of
occasions, including under SP4.

I'm not aware as yet that there is any known cause, but
it is not a difficult problem to workaround -- schedule
a batch job to run once a day at midnight (or even once
a week seems to work fine) under the admin
account that executes these two commands on the server:

net stop dns
net start dns

Restarting the DNS service this way will reset the cache
and seems to avoid the issue. This is not as graceful
as just solving the problem, but until that day this works
fine.

I have not witnessed this under 2003 Server, but I
have much less exposure to it to date.

Steve Duff, MCSE
Ergodic Systems, Inc.