List Domain Joined Servers

# ===========================================================================
# This script pulls a list of all domain joined servers and prints the
# last connected time.  The server is in red if this time is older than the
# number of days.  Beware that just because the server hasnt connected in
# the specified number of days, doesnt necessarily mean that the server
# can be deleted.  Instead, move the server into the Deactivated OU and
# only when you are sure, delete the server.
#
# May need to run this script as an OS user that is domain joined.
# ===========================================================================


$daysInactive = 30
$cutoffDate = (Get-Date).AddDays(-$daysInactive)

# Get all computer accounts
$computers = Get-ADComputer -Filter * -Properties Name, OperatingSystem, LastLogonTimeStamp, DistinguishedName

# Sort by name
$computers = $computers | Sort-Object Name

# Helper to extract OU path from DistinguishedName
function Get-OUFromDN($dn) {
    ($dn -split ',') -notmatch '^CN=' -join ','
}

# Display header
Write-Host ("{0,-30} {1,-30} {2,-22} {3}" -f "Name", "Operating System", "Last Logon", "Organizational Unit") -ForegroundColor Cyan

# Print each computer
foreach ($comp in $computers) {
    $lastLogon = [DateTime]::FromFileTime($comp.LastLogonTimeStamp)
    $isInactive = $lastLogon -lt $cutoffDate
    $os = if ($comp.OperatingSystem) { $comp.OperatingSystem } else { "Unknown / Possibly Linux" }
    $ou = Get-OUFromDN $comp.DistinguishedName

    $output = "{0,-30} {1,-30} {2,-22} {3}" -f $comp.Name, $os, $lastLogon, $ou

    if ($isInactive) {
        Write-Host $output -ForegroundColor Red
    } else {
        Write-Host $output -ForegroundColor Green
    }
}