I have computers on my LAN that keep getting IP conflict errrors

Posted on 2011-11-01
Last Modified: 2012-05-12
I have users reporting that they are recieving IP confilict errors on their computers.  How do I identify what computer is causing the conflict?  I am running Windows Server 2008 and the client is XP Pro.
Question by:submarinerssbn731
    LVL 8

    Accepted Solution

    If you go to a machine that doesn't have an IP address conflict, you can bring up a command prompt and do the following

    nbtstat -A <ip in conflict>

    That will reply with NetBIOS name associated with that IP address (if the machine doesn't have it's firewall up)...

    Alternativly, you can look in DHCP and see what machine has been given that IP address by the DHCP server...
    LVL 1

    Assisted Solution

    Try to remote connect to that IP then setup a (temporary) fix IP for it.
    You can run arp -a on a command prompt then see the MAC address. This might help

    Assisted Solution

    Click Start > All Programs > Administrative Tools > DHCP

    Your server should be listed there (assuming it's the DHCP server, and it should be)

    Expand your server name, > IPv4 > Scope > (double click Address Leases)

    Should show you all the reservations created on your network.  Get the IP addresses from the machines that are causing the issues, ensure that they don't have a static IP set (if you need help with this, ask and I can give you directions).

    You can then do one of two things.

    You can assign the ip addresses manually on the XP machine (which is my least favorite of the two options)

    Or you can set a address reservation in the "Reservations" pane under "Scope"

    I would create a reservation for the two machines that are conflicting.  Assigning them both different IP addresses.

    I would also open command prompt on the xp machines and run the following after making the reservations in scope:
    "ipconfig /flushdns"
    "ipconfig /release"
    "ipconfig /renew"

    That should eliminate your problems.


    Author Comment

    This is what I got when I ran the nbtstat.  Why does the DELLPURCHLG show up twice?

    C:\Program Files\Support Tools>nbtstat -A

    Local Area Connection:
    Node IpAddress: [] Scope Id: []

               NetBIOS Remote Machine Name Table

           Name               Type         Status
        DELLPURCHLG    <00>  UNIQUE      Registered
        DELLPURCHLG    <20>  UNIQUE      Registered
        PLASTICSOLUTION<00>  GROUP       Registered
        PLASTICSOLUTION<1E>  GROUP       Registered

        MAC Address = BC-30-5B-D8-8D-3F

    C:\Program Files\Support Tools>

    Author Closing Comment

    Good answers thanks,

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