DNS Cache Issues?

  • Thread starter Thread starter Ghad Von Bueler
  • Start date Start date
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Ghad Von Bueler

I have a Windows 2000 server w/ AD, DNS, DHCP that serves
our Windows desktops (2000, XP, etc..). We also have
some Unix machines which have DNS records setup in the
Win2K DNS server.

The DHCP server gives clients itself as a DNS server, as
well as an externel DNS server.

Occasionally this happens:

----
C:\>nslookup host1
Server: server.domain.com
Address: 192.168.0.11

Name: host1.domain.com
Address: 192.168.0.58


C:\>ping host1
Unknown host host1.

C:\>ipconfig /flushdns

Windows 2000 IP Configuration

Successfully flushed the DNS Resolver Cache.

C:\>ping host1

Pinging host1.domain.com [192.168.0.58] with 32 bytes of
data:
----

My theory: The client machine tries to lookup host1 and
for some reason queries the externel DNS server instead
of our internal Win2K machine. It then stores this info
in it's DNS cache.

Would only handing out one DNS server to DHCP clients fix
this? If so, WHY is this happening? Is this a Windows
desktop problem? I have similar networks running Unix
name servers with Windows desktops addressing both
internal and external machines and have never seen this
cache problem.

Thanks!
 
In
Ghad Von Bueler said:
I have a Windows 2000 server w/ AD, DNS, DHCP that serves
our Windows desktops (2000, XP, etc..). We also have
some Unix machines which have DNS records setup in the
Win2K DNS server.

The DHCP server gives clients itself as a DNS server, as
well as an externel DNS server.

Occasionally this happens:

----
C:\>nslookup host1
Server: server.domain.com
Address: 192.168.0.11

Name: host1.domain.com
Address: 192.168.0.58


C:\>ping host1
Unknown host host1.

C:\>ipconfig /flushdns

Windows 2000 IP Configuration

Successfully flushed the DNS Resolver Cache.

C:\>ping host1

Pinging host1.domain.com [192.168.0.58] with 32 bytes of
data:
----

My theory: The client machine tries to lookup host1 and
for some reason queries the externel DNS server instead
of our internal Win2K machine. It then stores this info
in it's DNS cache.

Would only handing out one DNS server to DHCP clients fix
this? If so, WHY is this happening? Is this a Windows
desktop problem? I have similar networks running Unix
name servers with Windows desktops addressing both
internal and external machines and have never seen this
cache problem.

Thanks!
Click to expand...

You should not use any external or ISP's that does not have the zone for
your local AD Domain in any position on any member of that domain.
 
Including the DNS/AD servers themselves?

Should I set those externel ISP DNS servers as Forwarders
on my DNS servers?
-----Original Message-----
In Ghad Von Bueler <[email protected]> posted a question
Then Kevin replied below:
I have a Windows 2000 server w/ AD, DNS, DHCP that serves
our Windows desktops (2000, XP, etc..). We also have
some Unix machines which have DNS records setup in the
Win2K DNS server.

The DHCP server gives clients itself as a DNS server, as
well as an externel DNS server.

Occasionally this happens:

----
C:\>nslookup host1
Server: server.domain.com
Address: 192.168.0.11

Name: host1.domain.com
Address: 192.168.0.58


C:\>ping host1
Unknown host host1.

C:\>ipconfig /flushdns

Windows 2000 IP Configuration

Successfully flushed the DNS Resolver Cache.

C:\>ping host1

Pinging host1.domain.com [192.168.0.58] with 32 bytes of
data:
----

My theory: The client machine tries to lookup host1 and
for some reason queries the externel DNS server instead
of our internal Win2K machine. It then stores this info
in it's DNS cache.

Would only handing out one DNS server to DHCP clients fix
this? If so, WHY is this happening? Is this a Windows
desktop problem? I have similar networks running Unix
name servers with Windows desktops addressing both
internal and external machines and have never seen this
cache problem.

Thanks!
Click to expand...

You should not use any external or ISP's that does not have the zone for
your local AD Domain in any position on any member of that domain.





.
Click to expand...
 
In (e-mail address removed) <[email protected]>
posted a question
Then Kevin replied below:
Including the DNS/AD servers themselves?
Click to expand...

Including the DNS server machine. The DNS server on this machine works
independently of the NIC setting, in fact the NIC must use the DNS server on
the machine for its DNS server.
Should I set those external ISP DNS servers as Forwarders
on my DNS servers?
Click to expand...
Forwarders are optional, but recommended and should be the only reference
for your ISP's DNS for the entire network.
300202 - HOW TO: Configure DNS for Internet Access in Windows 2000
http://support.microsoft.com/?id=300202&FR=1

-----Original Message-----
In
Ghad Von Bueler said:
I have a Windows 2000 server w/ AD, DNS, DHCP that serves
our Windows desktops (2000, XP, etc..). We also have
some Unix machines which have DNS records setup in the
Win2K DNS server.

The DHCP server gives clients itself as a DNS server, as
well as an externel DNS server.

Occasionally this happens:

----
C:\>nslookup host1
Server: server.domain.com
Address: 192.168.0.11

Name: host1.domain.com
Address: 192.168.0.58


C:\>ping host1
Unknown host host1.

C:\>ipconfig /flushdns

Windows 2000 IP Configuration

Successfully flushed the DNS Resolver Cache.

C:\>ping host1

Pinging host1.domain.com [192.168.0.58] with 32 bytes of
data:
----

My theory: The client machine tries to lookup host1 and
for some reason queries the externel DNS server instead
of our internal Win2K machine. It then stores this info
in it's DNS cache.

Would only handing out one DNS server to DHCP clients fix
this? If so, WHY is this happening? Is this a Windows
desktop problem? I have similar networks running Unix
name servers with Windows desktops addressing both
internal and external machines and have never seen this
cache problem.

Thanks!
Click to expand...

You should not use any external or ISP's that does not have the zone
for your local AD Domain in any position on any member of that
domain.





.
Click to expand...
Click to expand...
 
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