locating IP address conflict?

[michael brooks]

I'm running Windows XP home edition, with SP2.

I'm on a network which has probably 150 - 200 people connected via a series
of switches. Everyone is supposed to have their computer configured to get
the IP address automatically (DHCP?). Evidently at least one person is using
a fixed IP address (previously we were doing that, so someone failed to make
the change to automatic assignment).

The symptom of this is the following error message:
The system detected an address conflict for IP address 10.0.0.179 with the
system having network hardware address 00:00:B4:A7:F9:7D. Network operations
on this system may be disrupted as a result.

By the way, though I have only checked a few times, so far I've noticed that
the system always seems to assign me the same IP address (10.0.0.179) , even
though theoretically I'm not using a fixed address.

I am wondering if there is a simple way to locate the offending machine. One
idea was to use NET SEND to send a message to the offending address
(presumably 10.0.0.179), but (1) that may depend on having the messaging
service running on the offending machine and (2) I'm not sure if that works
with IP addresses.

Any ideas?

thanks!

[TIm]

Go into the DNS records on the DNS server and you can see what machine has
that IP. You can also do a nslookup from your machine to the IP and see if it
pulls the other machine up. To find out why you always get the same IP you
can look at two things 1. ipconfig /all to find out your lease time and two
you can go on the DHCP server and see if there is a reservation set up for
your machine.

"michael brooks" wrote:

> I'm running Windows XP home edition, with SP2.
>
> I'm on a network which has probably 150 - 200 people connected via a series
> of switches. Everyone is supposed to have their computer configured to get
> the IP address automatically (DHCP?). Evidently at least one person is using
> a fixed IP address (previously we were doing that, so someone failed to make
> the change to automatic assignment).
>
> The symptom of this is the following error message:
> The system detected an address conflict for IP address 10.0.0.179 with the
> system having network hardware address 00:00:B4:A7:F9:7D. Network operations
> on this system may be disrupted as a result.
>
> By the way, though I have only checked a few times, so far I've noticed that
> the system always seems to assign me the same IP address (10.0.0.179) , even
> though theoretically I'm not using a fixed address.
>
> I am wondering if there is a simple way to locate the offending machine. One
> idea was to use NET SEND to send a message to the offending address
> (presumably 10.0.0.179), but (1) that may depend on having the messaging
> service running on the offending machine and (2) I'm not sure if that works
> with IP addresses.
>
> Any ideas?
>
> thanks!
>
>
>

[Lem]

TIm wrote:
> Go into the DNS records on the DNS server and you can see what machine has
> that IP. You can also do a nslookup from your machine to the IP and see if it
> pulls the other machine up. To find out why you always get the same IP you
> can look at two things 1. ipconfig /all to find out your lease time and two
> you can go on the DHCP server and see if there is a reservation set up for
> your machine.
>
> "michael brooks" wrote:
>
>> I'm running Windows XP home edition, with SP2.
>>
>> I'm on a network which has probably 150 - 200 people connected via a series
>> of switches. Everyone is supposed to have their computer configured to get
>> the IP address automatically (DHCP?). Evidently at least one person is using
>> a fixed IP address (previously we were doing that, so someone failed to make
>> the change to automatic assignment).
>>
>> The symptom of this is the following error message:
>> The system detected an address conflict for IP address 10.0.0.179 with the
>> system having network hardware address 00:00:B4:A7:F9:7D. Network operations
>> on this system may be disrupted as a result.
>>
>> By the way, though I have only checked a few times, so far I've noticed that
>> the system always seems to assign me the same IP address (10.0.0.179) , even
>> though theoretically I'm not using a fixed address.
>>
>> I am wondering if there is a simple way to locate the offending machine. One
>> idea was to use NET SEND to send a message to the offending address
>> (presumably 10.0.0.179), but (1) that may depend on having the messaging
>> service running on the offending machine and (2) I'm not sure if that works
>> with IP addresses.
>>
>> Any ideas?
>>
>> thanks!
>>
>>
>>

nslookup might help if the computers have meaningful names (like
accounting 3, for example). I think there's a way to tell what switch a
particular unit is on, but I can't recall how at the moment. Maybe tracert?

As for getting the same IP address, that's "reallocation" --
http://www.tcpipguide.com/free/t_DHCPLeaseLifeCycleOverviewAllocationReallocation Re.htm

[michael brooks]

Lem & Tim: Many thanks for your help!

"Lem" > wrote in message
...
> TIm wrote:
>> Go into the DNS records on the DNS server and you can see what machine
>> has that IP. You can also do a nslookup from your machine to the IP and
>> see if it pulls the other machine up. To find out why you always get the
>> same IP you can look at two things 1. ipconfig /all to find out your
>> lease time and two you can go on the DHCP server and see if there is a
>> reservation set up for your machine.
>>
>> "michael brooks" wrote:
>>
>>> I'm running Windows XP home edition, with SP2.
>>>
>>> I'm on a network which has probably 150 - 200 people connected via a
>>> series of switches. Everyone is supposed to have their computer
>>> configured to get the IP address automatically (DHCP?). Evidently at
>>> least one person is using a fixed IP address (previously we were doing
>>> that, so someone failed to make the change to automatic assignment).
>>>
>>> The symptom of this is the following error message:
>>> The system detected an address conflict for IP address 10.0.0.179 with
>>> the system having network hardware address 00:00:B4:A7:F9:7D. Network
>>> operations on this system may be disrupted as a result.
>>>
>>> By the way, though I have only checked a few times, so far I've noticed
>>> that the system always seems to assign me the same IP address
>>> (10.0.0.179) , even though theoretically I'm not using a fixed address.
>>>
>>> I am wondering if there is a simple way to locate the offending machine.
>>> One idea was to use NET SEND to send a message to the offending address
>>> (presumably 10.0.0.179), but (1) that may depend on having the messaging
>>> service running on the offending machine and (2) I'm not sure if that
>>> works with IP addresses.
>>>
>>> Any ideas?
>>>
>>> thanks!
>>>
>>>
>>>
>
> nslookup might help if the computers have meaningful names (like
> accounting 3, for example). I think there's a way to tell what switch a
> particular unit is on, but I can't recall how at the moment. Maybe
> tracert?
>
> As for getting the same IP address, that's "reallocation" --
> http://www.tcpipguide.com/free/t_DHCPLeaseLifeCycleOverviewAllocationReallocation Re.htm