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Configure MDT for UserExit scripts

In this article, you'll learn how to configure the MDT rules engine to use a UserExit script to generate computer names based on a prefix and the computer MAC Address. MDT supports calling external VBScripts as part of the Gather process; these scripts are referred to as UserExit scripts. The script also removes the colons in the MAC Address.

Configure the rules to call a UserExit script

You can call a UserExit by referencing the script in your rules. Then you can configure a property to be set to the result of a function of the VBScript. In this example, we have a VBScript named Setname.vbs (provided in the book sample files, in the UserExit folder).


The UserExit=Setname.vbs calls the script and then assigns the computer name to what the SetName function in the script returns. In this sample, the %MACADDRESS% variable is passed to the script

The Setname.vbs UserExit script

The Setname.vbs script takes the MAC Address passed from the rules. The script then does some string manipulation to add a prefix (PC) and remove the semicolons from the MAC Address.

Function UserExit(sType, sWhen, sDetail, bSkip) 
  UserExit = Success 
End Function 
Function SetName(sMac)
  Dim re
  Set re = new RegExp
  re.IgnoreCase = true
  re.Global = true
  re.Pattern = ":"
  SetName = "PC" & re.Replace(sMac, "")
End Function

The first three lines of the script make up a header that all UserExit scripts have. The interesting part is the lines between Function and End Function. Those lines add a prefix (PC), remove the colons from the MAC Address, and return the value to the rules by setting the SetName value.


The purpose of this sample isn't to recommend that you use the MAC Address as a base for computer naming, but to show you how to take a variable from MDT, pass it to an external script, make some changes to it, and then return the new value to the deployment process.