Writing the Query in VBScript

Now it's time to incorporate the query into a script. This time, I'll start with the shell of the script, which will read the computer names from the text file.

That is easy enough. Now, for each, I need to retrieve a specified instance of Win32_NetworkAdapter. The caption I'm looking for-"Local Area Connection"-is stored in a property named NetConnectionID.

TIP

How did I know which property to use? Simple: Wbemtest. I clicked EnumInstances and typed Win32_NetworkAdapter as the superclass name. Then, I double-clicked on the first instance that was returned to display its properties. I scrolled down, looking for "Local Area Connection" in the values column, and I found it in a property named NetConnectionID. If I hadn't found "Local Area Connection" at all, I would have tried the next instance in the list, and kept browsing until I found it.

Actually, I don't want to retrieve the Win32_NetworkAdapter instance at all. Instead, I need to retrieve all associated Win32_NetworkAdapterConfiguration instances. However, as I discovered earlier, I need to retrieve the DeviceID on my own, based on a simpler WQL query. Here's the modified script.

Dim oFSO, oTS, sComputer Dim oWMI, oConfigs, oConfig, oAdapters, oAdapter Set oFSO = CreateObject("Scripting.FileSystemObject") Set oTS = oFSO.OpenTextFile("c:\input.txt") Do Until oTS.AtEndOfStream sComputer = oTS.ReadLine oWMI = GetObject("winmgmts:\\" & _ sComputer & "\root\cimv2") Set oAdapters = oWMI.ExecQuery( _ "SELECT DeviceID FROM Win32_NetworkAdapter " & _ "WHERE NetConnectionID = 'Local Area Connection') For Each oAdapter in oAdapters Set oConfigs = oWMI.ExecQuery( _ "ASSOCIATORS OF {Win32_NetworkAdapter.DeviceID='" & _ oAdapter.DeviceID & "'} " & _ "WHERE RESULTCLASS = Win32_NetworkAdapterConfiguration") Next Loop

Of course, simply retrieving the class doesn't do anything. Keep in mind that oConfigs will contain a collection of Win32_NetworkAdapterConfiguration instances, although in almost all cases the collection will only contain one instance. I'll need to loop through the instances and check each one to see if DHCP is enabled. Here's how.

Dim oFSO, oTS, sComputer Dim oWMI, oConfigs, oConfig Set oFSO = CreateObject("Scripting.FileSystemObject") Set oTS = oFSO.OpenTextFile("c:\input.txt") Do Until oTS.AtEndOfStream sComputer = oTS.ReadLine oWMI = GetObject("winmgmts:\\" & _ sComputer & "\root\cimv2") Set oAdapters = oWMI.ExecQuery( _ "SELECT DeviceID FROM Win32_NetworkAdapter " & _ "WHERE NetConnectionID = 'Local Area Connection') For Each oAdapter in oAdapters Set oConfigs = oWMI.ExecQuery( _ "ASSOCIATORS OF {Win32_NetworkAdapter.DeviceID='" & _ oAdapter.DeviceID & "'} " & _ "WHERE RESULTCLASS = Win32_NetworkAdapterConfiguration") For Each oConfig In oConfigs If oConfig.DHCPEnabled Then WScript.Echo "DHCP Enabled on " & sComputer Else WScript.Echo "Enabling DHCP on " & sComputer oConfig.EnableDHCP End If Next Next Loop

That's it! The script will read the text file and set each computer's "Local Area Connection" to use DHCP. If you'd like to test it, Listing 19.1 shows the complete listing, along with in-line comments.

Listing 19.1. SetDHCP.vbs. This script sets the Local Area Connection adapter to use DHCP for each computer named in text file.

Dim oFSO, oTS, sComputer Dim oWMI, oConfigs, oConfig 'get a filesystemobject and open the input file Set oFSO = CreateObject("Scripting.FileSystemObject") Set oTS = oFSO.OpenTextFile("c:\input.txt") 'for each line of the input file... Do Until oTS.AtEndOfStream 'read the computer name from the file sComputer = oTS.ReadLine 'connect to WMI on the remote computer oWMI = GetObject("winmgmts:\\" & _ sComputer & "\root\cimv2") 'query a collection of Win32_NetworkAdapter 'instances that have a NetConnectionID of ' Local Area Connection Set oAdapters = oWMI.ExecQuery( _ "SELECT DeviceID FROM Win32_NetworkAdapter " & _ "WHERE NetConnectionID = 'Local Area Connection') 'for each of those adapters... For Each oAdapter in oAdapters 'query the associated network adapter configurations Set oConfigs = oWMI.ExecQuery( _ "ASSOCIATORS OF {Win32_NetworkAdapter.DeviceID='" & _ oAdapter.DeviceID & "'} " & _ "WHERE RESULTCLASS = Win32_NetworkAdapterConfiguration'") 'for each of those configurations... For Each oConfig In oConfigs 'is DHCP enabled? If oConfig.DHCPEnabled Then 'yes - display a message WScript.Echo "DHCP Enabled on " & sComputer Else 'no - display a message and enable it WScript.Echo "Enabling DHCP on " & sComputer oConfig.EnableDHCP End If Next Next Loop

You'll need to provide the appropriate input file, c:\input.txt, in order to use this script.