preventing caching on DNS server

  • Thread starter Thread starter brian
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brian

Is there an easy way to prevent DNS server from caching
forwarded lookups?

Config:

Standalone DNS server is configured to forward all
requests to this box to an external DNS server for
lookups.

No root namespace on this box.

It will allow us to view webpages normally for
approximately 1 day, then give us errors the following.

any help would be appreciated.
 
I could be wrong on this, but I think the only way for you to do this is to
do a daily "net stop/net start dns" on the DNS server. This will clear the
Cache. My thinking is that the DNS will always obey the TTL specified for
any record it resolves, so there is no mechanism for it to go back and ask
for the record again UNLESS it does not have it anymore in its Cache.

--
Sincerely,

Dèjì Akómöláfé, MCSE MCSA MCP+I
www.akomolafe.com
www.iyaburo.com
Do you now realize that Today is the Tomorrow you were worried about
Yesterday? -anon
 
I could be wrong on this, but I think the only way for you to do this is
to
do a daily "net stop/net start dns" on the DNS server. This will clear the
Cache. My thinking is that the DNS will always obey the TTL specified for
any record it resolves, so there is no mechanism for it to go back and ask
for the record again UNLESS it does not have it anymore in its Cache.
Click to expand...

This also begs the question of WHY would anyone want to disable server
side caching in such a case. If the server shouldn't cache then the clients
should just be configured to use the UPSTREAD (forwarder) DNS server
directly.

The net traffic would be the same.

But if you wish to clear the cache you can do this WITHOUT stopping the
server: DNScmd.exe /clearcache
 
In
brian said:
Is there an easy way to prevent DNS server from caching
forwarded lookups?

Config:

Standalone DNS server is configured to forward all
requests to this box to an external DNS server for
lookups.

No root namespace on this box.

It will allow us to view webpages normally for
approximately 1 day, then give us errors the following.

any help would be appreciated.
Click to expand...

Set a MaxCacheTtl value in the registry of 0
I believe the MaxCacheTtl value is in part 1 below.
198408 Microsoft DNS Server Registry Parameters, Part 1 of 3
http://support.microsoft.com/default.aspx?scid=kb;EN-US;198408

198409 Microsoft DNS Server Registry Parameters, Part 2 of 3
http://support.microsoft.com/default.aspx?scid=kb;EN-US;198409

198410 Microsoft DNS Server Registry Parameters, Part 3 of 3
http://support.microsoft.com/default.aspx?scid=kb;EN-US;198410
 
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