1. I'd like to make our clients (xp) update (flush) its cached DNS
information more often. How can I do it from a central point? DHCP or GPO

2. what's the default? how to check?

Thanks.

Hello Chris,

For what reason? If the machine starts up it will register in DNS.

Best regards

Meinolf Weber
Disclaimer: This posting is provided "AS IS" with no warranties, and confers
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> 1. I'd like to make our clients (xp) update (flush) its cached DNS
> information more often. How can I do it from a central point? DHCP
> or GPO
>
> 2. what's the default? how to check?
>
> Thanks.
>

In message <AED1A63B-E42D-4749-8A86-2F3D7EE95B66@microsoft.com> Chris
<Chris@discussions.microsoft.com> wrote:

>1. I'd like to make our clients (xp) update (flush) its cached DNS
>information more often. How can I do it from a central point? DHCP or GPO
>
>2. what's the default? how to check?

In short, you can't. DNS caches are based on TTLs (time-to-live) which
is based on the TTL received by the authoritative host.

If you want to change the TTLs, the correct point to do it is in the DNS
zone authoritative for the particular domain you're querying.

I should make it more clear. I'm talking about local DNS resolver cache. I
know the registry change but want to know if there is a way or easy way to do
it from a central point.

"Meinolf Weber" wrote:

> Hello Chris,
>
> For what reason? If the machine starts up it will register in DNS.
>
> Best regards
>
> Meinolf Weber
> Disclaimer: This posting is provided "AS IS" with no warranties, and confers
> no rights.
> ** Please do NOT email, only reply to Newsgroups
> ** us YOU!!! http://www.blakjak.demon.co.uk/mul_crss.htm
>
> > 1. I'd like to make our clients (xp) update (flush) its cached DNS
> > information more often. How can I do it from a central point? DHCP
> > or GPO
> >
> > 2. what's the default? how to check?
> >
> > Thanks.
> >
>
>
>

"DevilsPGD" <spam_narf_spam@crazyhat.net> wrote in message
news:ashf04l34aqemq3ge7rsr6o7o77okf6g3b@4ax.com...
> In message <AED1A63B-E42D-4749-8A86-2F3D7EE95B66@microsoft.com> Chris
> <Chris@discussions.microsoft.com> wrote:
>
>>1. I'd like to make our clients (xp) update (flush) its cached DNS
>>information more often. How can I do it from a central point? DHCP or
>>GPO
>>
>>2. what's the default? how to check?
>
> In short, you can't. DNS caches are based on TTLs (time-to-live) which
> is based on the TTL received by the authoritative host.
>
> If you want to change the TTLs, the correct point to do it is in the DNS
> zone authoritative for the particular domain you're querying.

Personally I don't think he should do this -- but I believe there is a
MAXIMUM
TTL for the Client side cache with a default of 1 day. I also believe there
is
a registry setting that can reduce the max.

His machine will still respect the OWNER'S TTL if it is less than this max.

Read inline please.

In news:AED1A63B-E42D-4749-8A86-2F3D7EE95B66@microsoft.com,
Chris <Chris@discussions.microsoft.com> typed:
> 1. I'd like to make our clients (xp) update (flush) its cached DNS
> information more often. How can I do it from a central point? DHCP
> or GPO

If you want to completely clear the client cache every so often, you can
create a batch file with
ipconfig /flushdns as the command line. Then create a scheduled task to run
the batch file.

>
> 2. what's the default? how to check?
You can also reduce the maxcachettl value on the DNS client.
The default Maximum cached ttl is 86400 seconds(1 day) on XP, that doesn't
mean all records are cached that long. The client caches the remaining ttl
of the record when it actually receives it, so if a record has a 1 hour ttl
on the authoritative servers, and the client gets the record from a second
or third DNS server, the client only gets the remaining cache time from the
DNS server it uses, not what the authoritative server's TTL is. By the time
you get the record, it may only have 1 minute remaining TTL from the server.


How to Disable Client-Side DNS Caching in Windows XP and Windows Server 2003
http://support.microsoft.com/kb/318803

--
Best regards,
Kevin D. Goodknecht Sr. [MVP]
Hope This s

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