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DNS allowing same ip for multiple clients

Last response: in Windows 2000/NT
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May 22, 2005 11:57:33 PM

Archived from groups: microsoft.public.win2000.dns (More info?)

the DNS server (windows server 2003) appears to be allocating the same ip
address for multiple computers.

obviously this is causing connectivity problems across the LAN.

for example when using VNC when i type in the name of the client pc (eg
comp1) i connect to comp3. Very strange......

how do i prevent the dns from giving the same ip address to more that one
pc? I didn't think this was possible.
Anonymous
May 23, 2005 7:44:16 AM

Archived from groups: microsoft.public.win2000.dns (More info?)

On Sun, 22 May 2005 19:57:33 -0700, "bill"
<bill@discussions.microsoft.com> wrote:

>the DNS server (windows server 2003) appears to be allocating the same ip
>address for multiple computers.

DNS doesn't allocate IP's.

>obviously this is causing connectivity problems across the LAN.

No it isn't. Having the same IP on two systems will cause problems,
but DNS just registers the IP, it has nopthing to do with how the
system gets the IP address.

>for example when using VNC when i type in the name of the client pc (eg
>comp1) i connect to comp3. Very strange......

Not really. If DNS points "comp1" to the IP address currently used by
comp3, this is normal.

>how do i prevent the dns from giving the same ip address to more that one
>pc? I didn't think this was possible.

You can't. DNS doesn't assign IP's. DHCP does, or can. Configure
your systems and your DHCP correctly.

Now, do you really have systems with the same IP or do you have an
issue with DNS records showing two names pointing to the same IP? If
the latter, delete the incorrect record.

Jeff
May 23, 2005 7:44:17 AM

Archived from groups: microsoft.public.win2000.dns (More info?)

ok i ping both ip addresses that appear to be assigned to the one pc. both
resolve to the same FQD.

is this not DNS?

"Jeff Cochran" wrote:

> On Sun, 22 May 2005 19:57:33 -0700, "bill"
> <bill@discussions.microsoft.com> wrote:
>
> >the DNS server (windows server 2003) appears to be allocating the same ip
> >address for multiple computers.
>
> DNS doesn't allocate IP's.
>
> >obviously this is causing connectivity problems across the LAN.
>
> No it isn't. Having the same IP on two systems will cause problems,
> but DNS just registers the IP, it has nopthing to do with how the
> system gets the IP address.
>
> >for example when using VNC when i type in the name of the client pc (eg
> >comp1) i connect to comp3. Very strange......
>
> Not really. If DNS points "comp1" to the IP address currently used by
> comp3, this is normal.
>
> >how do i prevent the dns from giving the same ip address to more that one
> >pc? I didn't think this was possible.
>
> You can't. DNS doesn't assign IP's. DHCP does, or can. Configure
> your systems and your DHCP correctly.
>
> Now, do you really have systems with the same IP or do you have an
> issue with DNS records showing two names pointing to the same IP? If
> the latter, delete the incorrect record.
>
> Jeff
>
Related resources
May 23, 2005 7:44:18 AM

Archived from groups: microsoft.public.win2000.dns (More info?)

thanks for the response.

checked DHCP there are two seperate ip addresses. nothing appears unusall.

removed both dns entries and ipconfig /flushdns and /registerdns on both the
effected pcs.

they still appear to have the same ip address an the original problem.



"bill" wrote:

> ok i ping both ip addresses that appear to be assigned to the one pc. both
> resolve to the same FQD.
>
> is this not DNS?
>
> "Jeff Cochran" wrote:
>
> > On Sun, 22 May 2005 19:57:33 -0700, "bill"
> > <bill@discussions.microsoft.com> wrote:
> >
> > >the DNS server (windows server 2003) appears to be allocating the same ip
> > >address for multiple computers.
> >
> > DNS doesn't allocate IP's.
> >
> > >obviously this is causing connectivity problems across the LAN.
> >
> > No it isn't. Having the same IP on two systems will cause problems,
> > but DNS just registers the IP, it has nopthing to do with how the
> > system gets the IP address.
> >
> > >for example when using VNC when i type in the name of the client pc (eg
> > >comp1) i connect to comp3. Very strange......
> >
> > Not really. If DNS points "comp1" to the IP address currently used by
> > comp3, this is normal.
> >
> > >how do i prevent the dns from giving the same ip address to more that one
> > >pc? I didn't think this was possible.
> >
> > You can't. DNS doesn't assign IP's. DHCP does, or can. Configure
> > your systems and your DHCP correctly.
> >
> > Now, do you really have systems with the same IP or do you have an
> > issue with DNS records showing two names pointing to the same IP? If
> > the latter, delete the incorrect record.
> >
> > Jeff
> >
Anonymous
May 23, 2005 7:44:19 AM

Archived from groups: microsoft.public.win2000.dns (More info?)

See my response to your other older post "DNS problem" dated 5.19.05


"bill" wrote:

> thanks for the response.
>
> checked DHCP there are two seperate ip addresses. nothing appears unusall.
>
> removed both dns entries and ipconfig /flushdns and /registerdns on both the
> effected pcs.
>
> they still appear to have the same ip address an the original problem.
>
>
>
> "bill" wrote:
>
> > ok i ping both ip addresses that appear to be assigned to the one pc. both
> > resolve to the same FQD.
> >
> > is this not DNS?
> >
Anonymous
May 23, 2005 3:44:36 PM

Archived from groups: microsoft.public.win2000.dns (More info?)

On Sun, 22 May 2005 21:38:02 -0700, "bill"
<bill@discussions.microsoft.com> wrote:

>thanks for the response.
>
>checked DHCP there are two seperate ip addresses. nothing appears unusall.
>
>removed both dns entries and ipconfig /flushdns and /registerdns on both the
>effected pcs.
>
>they still appear to have the same ip address an the original problem.

Did you check the client TCP/IP settings?

Jeff


>"bill" wrote:
>
>> ok i ping both ip addresses that appear to be assigned to the one pc. both
>> resolve to the same FQD.
>>
>> is this not DNS?
>>
>> "Jeff Cochran" wrote:
>>
>> > On Sun, 22 May 2005 19:57:33 -0700, "bill"
>> > <bill@discussions.microsoft.com> wrote:
>> >
>> > >the DNS server (windows server 2003) appears to be allocating the same ip
>> > >address for multiple computers.
>> >
>> > DNS doesn't allocate IP's.
>> >
>> > >obviously this is causing connectivity problems across the LAN.
>> >
>> > No it isn't. Having the same IP on two systems will cause problems,
>> > but DNS just registers the IP, it has nopthing to do with how the
>> > system gets the IP address.
>> >
>> > >for example when using VNC when i type in the name of the client pc (eg
>> > >comp1) i connect to comp3. Very strange......
>> >
>> > Not really. If DNS points "comp1" to the IP address currently used by
>> > comp3, this is normal.
>> >
>> > >how do i prevent the dns from giving the same ip address to more that one
>> > >pc? I didn't think this was possible.
>> >
>> > You can't. DNS doesn't assign IP's. DHCP does, or can. Configure
>> > your systems and your DHCP correctly.
>> >
>> > Now, do you really have systems with the same IP or do you have an
>> > issue with DNS records showing two names pointing to the same IP? If
>> > the latter, delete the incorrect record.
>> >
>> > Jeff
>> >
Anonymous
May 23, 2005 3:48:59 PM

Archived from groups: microsoft.public.win2000.dns (More info?)

On Sun, 22 May 2005 21:22:02 -0700, "bill"
<bill@discussions.microsoft.com> wrote:

>ok i ping both ip addresses that appear to be assigned to the one pc. both
>resolve to the same FQD.

Okay, two IP address under one name or two names pointing to the same
IP address?

>is this not DNS?

That's DNS. But you said your PC's were getting allocated the same IP
address. That's not DNS.

Check the client PC for TCP/IP settings. If it's static, check both
to make sure you have two separate IP addresses. Actually, check if
it's dynamic as well. At a command prompt on the client do a IPCONFIG
/ALL and look at the IP addresses and see how they are assigned (is
there a DHCP server).

If the IP's are different, remove both IP addresses in your DNS
server. If you use dynamic IP registration in your DNS, do not add
them again. If you do not, manually add an A record for each system
name with the correct IP. Turn *everything* off and back on again.
Check the IP's on the clients. Ping the IP address. Then ping by
name.

Jeff

>"Jeff Cochran" wrote:
>
>> On Sun, 22 May 2005 19:57:33 -0700, "bill"
>> <bill@discussions.microsoft.com> wrote:
>>
>> >the DNS server (windows server 2003) appears to be allocating the same ip
>> >address for multiple computers.
>>
>> DNS doesn't allocate IP's.
>>
>> >obviously this is causing connectivity problems across the LAN.
>>
>> No it isn't. Having the same IP on two systems will cause problems,
>> but DNS just registers the IP, it has nopthing to do with how the
>> system gets the IP address.
>>
>> >for example when using VNC when i type in the name of the client pc (eg
>> >comp1) i connect to comp3. Very strange......
>>
>> Not really. If DNS points "comp1" to the IP address currently used by
>> comp3, this is normal.
>>
>> >how do i prevent the dns from giving the same ip address to more that one
>> >pc? I didn't think this was possible.
>>
>> You can't. DNS doesn't assign IP's. DHCP does, or can. Configure
>> your systems and your DHCP correctly.
>>
>> Now, do you really have systems with the same IP or do you have an
>> issue with DNS records showing two names pointing to the same IP? If
>> the latter, delete the incorrect record.
>>
>> Jeff
>>
Anonymous
May 25, 2005 1:45:59 AM

Archived from groups: microsoft.public.win2000.dns (More info?)

Jeff Cochran wrote:
> On Sun, 22 May 2005 21:22:02 -0700, "bill"
> <bill@discussions.microsoft.com> wrote:
>
>> ok i ping both ip addresses that appear to be assigned to the one
>> pc. both resolve to the same FQD.
>
> Okay, two IP address under one name or two names pointing to the same
> IP address?
>
>> is this not DNS?
>
> That's DNS. But you said your PC's were getting allocated the same IP
> address. That's not DNS.
>
> Check the client PC for TCP/IP settings. If it's static, check both
> to make sure you have two separate IP addresses. Actually, check if
> it's dynamic as well. At a command prompt on the client do a IPCONFIG
> /ALL and look at the IP addresses and see how they are assigned (is
> there a DHCP server).
>
> If the IP's are different, remove both IP addresses in your DNS
> server. If you use dynamic IP registration in your DNS, do not add
> them again. If you do not, manually add an A record for each system
> name with the correct IP. Turn *everything* off and back on again.
> Check the IP's on the clients. Ping the IP address. Then ping by
> name.
>
> Jeff

I just want to add we may need to check WINS here too, if he's using WINS.


--
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
=================================
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