Archived from groups: microsoft.public.win2000.dns (
More info?)
In news:4df8d57a.0408310134.1f869ca7@posting.google.com,
Dilan Weerasinghe <dilanw77@hotmail.com> wrote their comments
Then Kevin replied below:
> "Ace Fekay [MVP]"
> <PleaseSubstituteMyActualFirstName&LastNameHere@hotmail.com>
> wrote in message
> news:<OJwdojDjEHA.3712@TK2MSFTNGP15.phx.gbl>...
>> In news:4df8d57a.0408261146.354d51da@posting.google.com,
>> Dilan Weerasinghe <dilanw77@hotmail.com> made a post
>> then I commented below
>>> "Kevin D. Goodknecht Sr. [MVP]" <admin@nospam.WFTX.US>
>>> wrote in message
>>> news:<u7FbX92iEHA.2052@TK2MSFTNGP15.phx.gbl>...
>>>> In
>>>> news:4df8d57a.0408260441.3946cd3a@posting.google.com,
>>>> Dilan Weerasinghe <dilanw77@hotmail.com> wrote their
>>>> comments
>>>> Then Kevin replied below:
>>>>> Hi NG,
>>>>>
>>>>> We have noticed that several of our PC's suddenly
>>>>> seem to lose their ability to browse the net, connect
>>>>> to our Exchange server etc. Basic troubleshooting
>>>>> showed that although the actual connectivity was
>>>>> there, name resolution seemed to be causing the
>>>>> problem, i.e. we could ping internally/externally by
>>>>> IP address but not by name.
>>>>>
>>>>> Checking the IPCONFIG showed that these machines,
>>>>> which are all set to DHCP, seemed to be picking up a
>>>>> phantom DNS server as opposed to the correct one, e.g.
>>>>> 192.168.1.12 as opposed to 192.168.1.1
>>>>>
>>>>> Rebooting the machines resolves the problem.
>>>>>
>>>>> When we try to ping the phantom DNS server, we do not
>>>>> get a reply. That address itself is excluded from our
>>>>> DHCP range and is not currently being used, so i have
>>>>> no idea why these workstations are picking this same
>>>>> address all the time.
>>>>>
>>>>> Has anyone experienced this before, or have any
>>>>> pointers?? All other settings in IPCONFIG are correct,
>>>>> and we have not made any changes to our
>>>>> infrastructure/architecture recently.
>>>>
>>>> It is possible for your clients to get the DNS address
>>>> from a Group policy, it would not show in the ipconfig
>>>> /all but when running nslookup you will get it.
>>>> You're saying that there is no machine at 192.168.1.12?
>>>> And that the DHCP server is publishing the address of
>>>> the local DNS server 192.168.1.1 and not the IP of the
>>>> router?
>>>> Are you using DHCP on the server or the router? (if
>>>> you have a router)
>>>>
>>>>
>>>>
>>> Thanks for the reply.
>>>
>>> No, there is no machine at all on 192.168.1.12, and the
>>> DHCP server is configured correctly to give a DNS
>>> server address of 192.168.1.1.
>>> We are using a DHCP server that has a different address
>>> altogether.
>>>
>>> The strange thing is that this switch happens whilst a
>>> user is logged on and has been for a while...not on
>>> machine start up or logon.
>>>
>>> Any ideas?
>>>
>>> Dilan
>>
>> I think we're going to need more info to help you out on
>> this one.
>>
>> Is 192.168.1.1 your router? If it is, is it a Windows
>> machine or a 3rd party router?
>>
>> If you disable DHCP on the 192.168.1.1 machine, and then
>> do an ipconfig /release and then an ipconfig /renew,
>> what DHCP server shows up in the ipconfig /all?
>>
>> Honestly, if 192.168.1.1 is not a Windows machine, it
>> would be to your advantage, and to AD and DNS'
>> advantage, to use a Windows machine for DHCP and DNS,
>> since the two services and APIs are tied together for
>> proper dynamic registration performance and reliability.
>>
>> If this is a Windows DHCP, did you set the Scope Option
>> 006 and Server Option 006?
>>
>> --
>> Regards,
>> Ace
>>
>> Please direct all replies ONLY to the Microsoft public
>> newsgroups
>> so all can benefit.
>>
>> This posting is provided "AS-IS" with no warranties or
>> guarantees
>> and confers no rights.
>>
>> Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I,
>> MCT, MVP
>> Microsoft Windows MVP - Windows Server - Directory
>> Services
>>
>> Security Is Like An Onion, It Has Layers
>> HAM AND EGGS: A day's work for a chicken;
>> A lifetime commitment for a pig.
>
> Ace,
>
> To clarify;
>
> Our network is configured as following -
>
> DHCP server: 192.168.1.1
> DNS Servers: 192.168.1.1/ 192.168.1.2
>
> (All above addresses are static)
>
> All workstations are set to DHCP, and I've checked the
> scope options
> on the DHCP server itself as regards DNS, and it points
> to the correct
> addresses.
>
> Our router is on a completely different address.
>
> The problem is that, randomly, users seem to lose their
> internet
> connection. As I mentioned before, the actual
> connectivity is there
> but the fault lies with name resolution as we can ping
> externally/internally by IP address but not by name.
> Checking the
> IPCONFIG shows that the faulty machines are picking up
> 192.168.1.10 as
> their DNS server, although all other settings are correct.
> Rebooting the machines solves the problem until it
> happens again.
> I understand that we could set the workstations to
> statically point at
> the correct DNS servers, however this is a workaround,
> not a solution
> and I'd like to find out what's causing this.
> The faulty machines always pick up x.10 as the DNS server.
> x.10 itself is excluded from our DHCP range for
> distribution, and is
> also not currently being used, so I have no idea why they
> are picking
> this address up as a DNS server.
>
> Many thanks for your help
> Dilan
On the ipconfig for the machines with the bogus DNS address, what IP do they
show for the DHCP server?
--
Best regards,
Kevin D4 Dad Goodknecht Sr. [MVP]
Hope This Helps
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