Computername zu MAC-Adresse zuordnen Powershell

$username = "domäne\user"  
$password = cat "C:\securestringmac.txt" | convertto-securestring  
$cred = new-object -typename System.Management.Automation.PSCredential `
         -argumentlist $username, $password
$strComputers = Get-Content "Rechnername.txt"  
foreach ($strComputer in $strComputers) { 
$colItems = Get-WmiObject -class "Win32_NetworkAdapterConfiguration" -Authentication Default -Credential $cred `  
-computername $strComputer | Where {$_.IPEnabled -Match "True"}  
foreach ($objItem in $colItems) { 
    $mac = $objItem.MACAddress
    Add-Content -Path "Mac.txt" -Value $mac  
    }
}