batch file to release an ip address when

Well, the command for releasing an IP address is: ipconfig /release. All you have to do to create a batch file to do this would be to put this in a text file and call it, for example, shutdown.bat. However, I don't know of any way to get this to run automatically every time you shut down Win2K unless you are on a domain and can use the logoff script option to do this. Hope this helps!