$urls = @(
    "www.google.de"
    "www.amazon.de"
    "www.github.com"
    "www.youtube.com"
    "www.gibtsnicht.com"
)

$start = Get-Date

$urls | ForEach-Object -Parallel {
    $reachable = Test-Connection -ComputerName $_ -Quiet
    if($reachable){
        Write-Host "$($_) is reachable"
    }else {
        Write-Host "$($_) could not be reached"
    }
}

$end = Get-Date
$duration = $end - $start


Write-Host "Laufzeit: $($duration.TotalSeconds)"