Re: Duplicate reverse lookup entries/nslookup problems

Thanks for the tip and link. I have one concern about scavenging though -
what happens with machines that have static ip's or are always on, like
servers? I turned on advanced view in the dns console and looked at some of
the "record time stamps". Some time stamps are nearly a year old on
machines that I can ping & know that they are active. Do I need to do
anything to make sure good records don't get scavenged?

"Todd J Heron [MVP]" <todd_heron(delete)@hotmail.com> wrote in message
news:OHB7aALGGHA.2568@xxxxxxxxxxxxxxxxxxxxxxx
> "Roger" <roger@xxxxxxxxxxx> wrote in message
> news:%23hRgKSKGGHA.3624@xxxxxxxxxxxxxxxxxxxxxxx
>> On my internal network, when using nslookup to resolve an ip to computer
>> name, it sometimes resolves to an incorrect host name. I looked into the
>> reverse lookup zone and found that there are duplicate entries for some
>> ip addresses, and lots of old entries. What should I do to keep it
>> accurate? I'm using dhcp to serve out addresses - I'm guessing that I
>> need to change something on the dhcp server or client end of things.
>
> Duplicate records may exist in DDNS due to DHCP not discarding A & PTR
> records. On the DHCP server, ensure "Discard A and PTR records when lease
> is deleted" is enabled under the DHCP server properties > DNS tab.
> However, this does not always clean everything up, as in instances where
> machines crash, are shutdown ungracefully, or say a laptop which is just
> disconnected. The IP is not released in any of these examples. A machine
> cannot update or delete a record when that record is created by another
> machine. The result is it creates another PTR record for the same IP
> address. The DHCP server also cannot update the record because it is not
> the owner. You need to enable scavenging to remove these records. There
> is a proactive approach which you can take via DHCP which Kevin Goodknecht
> often recommends. See link below.
>
> http://groups.google.com/group/microsoft.public.windows.server.dns/browse_thread/thread/34d1fe4a15bb7f36/1536576a349fbc19?lnk=st&q=%22
>
> --
> Todd J Heron, MVP Windows Server - Networking
> MCSE - Windows Server 2003/2000/NT; CCA
>


.

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