IP address already in use

I have started getting the "IP address already in use" error. I started
getting this after I brought down our old NT server and brought up a new 2k3
server. The server is the system that is getting this error from time to
time. The DHCP is a Sonicwall with the servers mac address set to a static
IP address in the DHCP. The problem doesnt seem to be causing any issues yet
but something isnt right.

I am also started getting this at my house after I hooked up a linksys
wireless router. I secured the wireless with WEP encryption. It isnt unusual
for me to come home after work and have 5+ of these dialog boxes to go
through. I leave that computer on 24x7.

Any possible causes? Both of these cases are completely different but I have
not seen this problem since I moved to DHCP years ago. Seems wierd that two
of these instances pop up in two completely seperate networks.

Thanks

Jon

Hi Javan,

You should be able to see something like this in your event log (at least on
the server)...

The system detected an address conflict for IP address 10.10.10.10 with the
system having network hardware address 00:0D:9D:93:E9:3B. Network operations
on this system may be disrupted as a result.

This "01:1D:9D:93:E9:3A" is a MAC address of the computer / device that is
causing the IP conflict. If you can locate this device by MAC address you
will know who/what is causing you the problems.

I hope this helps.

--
Mike
Microsoft MVP - Windows Security

"Javan" <(E-Mail Removed)> wrote in message
news:eYXNrI$(E-Mail Removed)...
>I have started getting the "IP address already in use" error. I started
>getting this after I brought down our old NT server and brought up a new
>2k3 server. The server is the system that is getting this error from time
>to time. The DHCP is a Sonicwall with the servers mac address set to a
>static IP address in the DHCP. The problem doesnt seem to be causing any
>issues yet but something isnt right.
>
> I am also started getting this at my house after I hooked up a linksys
> wireless router. I secured the wireless with WEP encryption. It isnt
> unusual for me to come home after work and have 5+ of these dialog boxes
> to go through. I leave that computer on 24x7.
>
> Any possible causes? Both of these cases are completely different but I
> have not seen this problem since I moved to DHCP years ago. Seems wierd
> that two of these instances pop up in two completely seperate networks.
>
> Thanks
>
> Jon
>

I might should know this, but I havent had a need until now. How can I
search the network by MAC address?
Jon

"Miha Pihler [MVP]" <mihap-(E-Mail Removed)> wrote in message
news:eNWKWP$(E-Mail Removed)...
> Hi Javan,
>
> You should be able to see something like this in your event log (at least
> on the server)...
>
> The system detected an address conflict for IP address 10.10.10.10 with
> the system having network hardware address 00:0D:9D:93:E9:3B. Network
> operations on this system may be disrupted as a result.
>
> This "01:1D:9D:93:E9:3A" is a MAC address of the computer / device that is
> causing the IP conflict. If you can locate this device by MAC address you
> will know who/what is causing you the problems.
>
> I hope this helps.
>
> --
> Mike
> Microsoft MVP - Windows Security
>
> "Javan" <(E-Mail Removed)> wrote in message
> news:eYXNrI$(E-Mail Removed)...
>>I have started getting the "IP address already in use" error. I started
>>getting this after I brought down our old NT server and brought up a new
>>2k3 server. The server is the system that is getting this error from time
>>to time. The DHCP is a Sonicwall with the servers mac address set to a
>>static IP address in the DHCP. The problem doesnt seem to be causing any
>>issues yet but something isnt right.
>>
>> I am also started getting this at my house after I hooked up a linksys
>> wireless router. I secured the wireless with WEP encryption. It isnt
>> unusual for me to come home after work and have 5+ of these dialog boxes
>> to go through. I leave that computer on 24x7.
>>
>> Any possible causes? Both of these cases are completely different but I
>> have not seen this problem since I moved to DHCP years ago. Seems wierd
>> that two of these instances pop up in two completely seperate networks.
>>
>> Thanks
>>
>> Jon
>>
>
>

Hi,

one (easy?) way is by using command

arp -a

It will display current ARP cache on the computer where you run the command.
If you want to see whole network -- you would have to connect to all hosts
(e.g. by using ping command) and then repeat command

arp -a

to see current MAC addresses in ARP cache.

You can use command

arp -a > MAC.txt

to store the output from arp cache to file for easier searching

You can search the internet for tools that can help you with this. E.g.
search for tools such as "ping subnet"...


Let me know if you need more assistance on this.

--
Mike
Microsoft MVP - Windows Security

"Javan" <(E-Mail Removed)> wrote in message
news:%23%23G$tW$(E-Mail Removed)...
>I might should know this, but I havent had a need until now. How can I
>search the network by MAC address?
> Jon
>
> "Miha Pihler [MVP]" <mihap-(E-Mail Removed)> wrote in message
> news:eNWKWP$(E-Mail Removed)...
>> Hi Javan,
>>
>> You should be able to see something like this in your event log (at least
>> on the server)...
>>
>> The system detected an address conflict for IP address 10.10.10.10 with
>> the system having network hardware address 00:0D:9D:93:E9:3B. Network
>> operations on this system may be disrupted as a result.
>>
>> This "01:1D:9D:93:E9:3A" is a MAC address of the computer / device that
>> is causing the IP conflict. If you can locate this device by MAC address
>> you will know who/what is causing you the problems.
>>
>> I hope this helps.
>>
>> --
>> Mike
>> Microsoft MVP - Windows Security
>>
>> "Javan" <(E-Mail Removed)> wrote in message
>> news:eYXNrI$(E-Mail Removed)...
>>>I have started getting the "IP address already in use" error. I started
>>>getting this after I brought down our old NT server and brought up a new
>>>2k3 server. The server is the system that is getting this error from
>>>time to time. The DHCP is a Sonicwall with the servers mac address set to
>>>a static IP address in the DHCP. The problem doesnt seem to be causing
>>>any issues yet but something isnt right.
>>>
>>> I am also started getting this at my house after I hooked up a linksys
>>> wireless router. I secured the wireless with WEP encryption. It isnt
>>> unusual for me to come home after work and have 5+ of these dialog boxes
>>> to go through. I leave that computer on 24x7.
>>>
>>> Any possible causes? Both of these cases are completely different but I
>>> have not seen this problem since I moved to DHCP years ago. Seems wierd
>>> that two of these instances pop up in two completely seperate networks.
>>>
>>> Thanks
>>>
>>> Jon
>>>
>>
>>
>
>