NSLOOKUP using IP address gives WRONG DNS names...

[Darren F.]

We noticed yesterday that when we do a NSLOOKUP on an IP address, the
response is not correct. It gives a series of incorrect DNS names, and
then the correct name, and then repeats the series again.

For example, I enter 172.1.1.1 over and over, and I get a different
response each time. The response comes back something like "BOB",
"SUE", "JOHN", "MARY", "BOB", "SUE", etc.

The correct entry should have been "MARY".

When we do a lookup on "MARY", we get 172.1.1.1. The others return
their correct IP addresses also.

Any ideas?

We are using Windows 2003 Server. We recently switched from Windows
2000 Server.

Thanks in advance.

Darren

 

[Kevin D. Goodknecht Sr. [MVP]]

In

We noticed yesterday that when we do a NSLOOKUP on an IP
address, the response is not correct. It gives a series
of incorrect DNS names, and then the correct name, and
then repeats the series again.

For example, I enter 172.1.1.1 over and over, and I get a
different response each time. The response comes back
something like "BOB", "SUE", "JOHN", "MARY", "BOB",
"SUE", etc.

The correct entry should have been "MARY".

When we do a lookup on "MARY", we get 172.1.1.1. The
others return their correct IP addresses also.

Any ideas?

We are using Windows 2003 Server. We recently switched
from Windows 2000 Server.

It sounds like the old PTR records are staying in DNS, you can delete them
set scavenging on the zone or ignore it. PTR records are not necessary for
network communication. Though I know it may be irritating for you.

 

[Herb Martin]

We noticed yesterday that when we do a NSLOOKUP on an IP address, the
response is not correct. It gives a series of incorrect DNS names, and
then the correct name, and then repeats the series again.

For example, I enter 172.1.1.1 over and over, and I get a different
response each time. The response comes back something like "BOB",
"SUE", "JOHN", "MARY", "BOB", "SUE", etc.

The correct entry should have been "MARY".

When we do a lookup on "MARY", we get 172.1.1.1. The others return
their correct IP addresses also.

This implies you have a BUNCH of entries for 172.1.1.1 and
"round robin" is rotating them.

While this is uncommon with REVERSE entries (and makes
little sense) it is legal just like having multiple A records for
a Host with different IPs for the same name.

Go look at the reverse zone on the Primary and see what is there.

If you are letting clients dynamically register in DNS it COULD
be due to different machines using the address but I would have
thought that would overwrite each time a new one registered.

If you are using DHCP to set the dynamic DNS make sure you have
it set to remove the records on lease experiation.

 

[Jim Graham]

Any luck with this? I am experiencing the same exact
problems, and scavenging IS enabled for the Reverse
Lookup Zone... I know Server 2000 had a problem with
this, but was it not fixed in 2003? Why aren't these
stale records being scavenged?

Jim Graham