Tech Tip: Change a remote system from static to dynamic IP

You may occasionally need to change a remote system from a static IP to a dynamic IP (DHCP). Follow these steps:

1. Open the Registry Editor (Regedt32).
2. Navigate to HKEY_LOCAL_MACHINE\
   SOFTWARE\Microsoft\
   Windows NT\CurrentVersion\
   NetworkCards\1 (or whatever number card you need to change--some machines may have multiples), and record the ServiceName value.
3. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ Services\<ServiceName>\Parameters\TCPIP, where <ServiceName> is the name you recorded in the previous step.
4. Change the values of EnableDHCP to 1 and IPAddress And SubnetMask to 0.0.0.0.
5. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ Services\DHCP, and change the Start value to 2.

Locate conflicting IP address sources

If you ever receive the error of having a conflicting IP address, you may want to know who the culprit is. Even in a large corporation, this is easier to determine than you might think. You need only arm yourself with another workstation and the stolen IP address.

First, open a command prompt on the working workstation or server. Now, enter the command nbtstat -a <IPAddress>, where <IPAddress> is the stolen IP. Look at the results returned. When we tested this on our NT server, the results from the workstation were:

Notice the two records with <03> as the NetBIOS type. One is the machine name; the other is the logon name. Armed with the logon name, you now know who has logged on to the workstation with your IP. If no one has logged on yet, you still have the machine name and should be able to track down the culprit with that.

Editor's note: Remember that editing the registry can be risky; always have a verified backup before you begin.