On Error Resume Next

RegPath = "HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\"
Set objWMIService = GetObject("winmgmts:{impersonationLevel=impersonate}!\\.\root\cimv2")
Set objNetworkSettings = objWMIService.Get("Win32_NetworkAdapterConfiguration")
'objNetworkSettings.SetMTU(1500)

Set colItems = objWMIService.Execquery ("Select * From Win32_NetworkAdapterConfiguration Where IPEnabled = True")
Set objShell = WScript.CreateObject("WScript.shell")

    For Each objItem in colItems
        RetVal = objItem.SettingID
        objShell.RegWrite RegPath & RetVal & "\MTU", 1500, "REG_DWORD"
        'Wscript.Echo RegPath & RetVal & "\MTU"
    Next

If Err.Number = 0 Then
    Wscript.Echo "Successfully set the MTU to 1500"
Else
    Wscript.Echo "Failed to set the MTU to 1500"
End If