function Convert-DNStoDN ([string]$DNSName)
{
   #  Create an array of each item in the string separated by "."
   $DNSArray = $DNSName.Split(".")
  # Let's go through our new array and do something with each item
   for ($x = 0; $x -lt $DNSArray.Length ; $x++)
      {
        #I don't want a comma after my last item, so check to see if I am on my last one and set
        # $Separator equal to nothing.
        # Remember that we need to go to Length-1 because arrays are "0 based indexes"
         if ($x -eq ($DNSArray.Length - 1)){$Separator = ""}else{$Separator =","}
         [string]$DN += "DC=" + $DNSArray[$x] + $Separator
      }
   return $DN
}

function Convert-DNtoDNS ([string]$DN)
{
    $DNArray = $DN.Split(",")
     # Let's go through our new array and do something with each item
   for ($x = 0; $x -lt $DNArray.Length ; $x++)
      {
        #I don't want a period after my last item, so check to see if I am on my last one and set
        # $Separator equal to nothing.
        # Remember that we need to go to Length-1 because arrays are "0 based indexes"
         if ($x -eq ($DNArray.Length - 1)){$Separator = ""}else{$Separator ="."}
        # Now we have to see if we look like "DC=". If it does, we will
        # start to construct our DNS name.
        if ($DNArray[$x].Split("=")[0] -ilike "DC")
          {
               # Let's grab the "contoso" side of the "DC=contoso"
              [string]$DNS += $DNArray[$x].Split("=")[1] + $Separator
           }
      }
   return $DNS
}

function get-groupmember([string]$domain, [string]$groupName)
{
   # I have passed in the FQDN and Groupname I am interested in
   # I just need to convert my FQDN into an LDAP style name using my previous function
   $DN = convert-DNStoDN($Domain)
   $domainLDAPUrl = "LDAP://" + $DN
   # Setup my directory connection using .NET call
   $ent = [System.DirectoryServices.DirectoryEntry] ( $domainLDAPUrl )
 
   # Define my "searcher" object to query the directory
   $srch = [System.DirectoryServices.DirectorySearcher] ( $ent )
 
   # Setup my search criteria.. looking for all Groups with CN=GroupName
   $groupNameFilter = "(&(objectClass=group)(CN=" + $groupName + "))"
   $srch.Filter = $groupNameFilter
 
   # Now go execute my query to and put the results in $coll
   $coll = [System.DirectoryServices.SearchResultCollection]      $srch.FindAll()
 
   foreach ($rs in $coll)
     {
       # Now get a collection of properties for that object
       $resultPropColl = [System.DirectoryServices.ResultPropertyCollection] $rs.Properties
 
       # Cycle through all group members
       foreach ($memberColl in $resultPropColl["member"])
         {
           # Build my membership array
           [array]$gpMemberEntry += [System.DirectoryServices.DirectoryEntry] ( "LDAP://" + $memberColl )
          }
   }
  # Send back my group members.
  return $gpMemberEntry
}

function get-allmembers($objectName, $OF, $GN)
{
    # Split out my domain name  (should be FQDN) and the group name
    $domainName = $objectname.split("\")[0]
    $ObjectName = $objectname.split("\")[1]
 
    $members = get-groupmember "$DomainName" "$ObjectName"
    if ($members -ne $NULL)
     {
        foreach ($member in $members)
         {
            #  Grab the domain DNS name out of the object DN
            $ObjDomain = convert-DNtoDNS $Member.DistinguishedName
            if ($member.objectclass -contains "group")
              {
                 #If my group member is, itself, a group We get to do some recursion
                  $out = $objDomain + "\" + $member.name
                  Write-Host $out
                  # Call myself with the nested group name
                  get-allmembers -ObjectName $out -OF $of -GN $GN
               }
            else
               {
                  # If I get back a user, then see if the user is disabled or not
                  $userAndDomain = $objDomain + "\" + $member.name
                  # The  UserAccountControl property contains several "flags"
                  # that we can interrogate.  By doing a Binary AND we are seeing if the 2nd flag is set.
                  [bool]$accountIsDisabled = [int]$member.userAccountControl.ToSTring() -band 2
 
                  # Setup our output (I am choosing to construct a comma-delimited type of output
                  $OutText = "'" + $GN + "','" + $objDomain + "','" + $Member.Samaccountname + "','" + $Member.displayName + "','" + $member.distinguishedName + "','" + $objectname + "','" + $accountIsDisabled + "'"
 
                  Out-File -FilePath $OF -inputobject $Outtext -append -Encoding "ASCII"
 
                  Write-Host $OutText
                }
         }
    }
    else
     {
        Write-Host "No Members or no Group:" $ObjectName "in Domain:" $DomainName -Foreground RED
     }
}
 
###########################
## Main
###########################
$GroupName = "Domain Admins"
$Today = Get-Date -format "yyyyMMddhh"
$OutputFolder = "C:\Temp\"
 
if ((Test-Path $outputFolder) -eq $False)
 {
    New-Item -Path $OutputFolder -Type Directory > $NULL
  }
 
# Grab my forest info
$forest = [System.DirectoryServices.ActiveDirectory.Forest]::GetCurrentForest()
 
#Setup my output file
$OutHeader = "'Group','UserDomain','SAMAccount','DisplayName','DN','MemberofGroup','IsDisabled'"
 
# Define output file name
$of = $OutputFolder + $Today +"_"+ $GroupName + "-AuditReport.txt"
 
Out-File -FilePath $OF -inputobject $OutHeader -Encoding "ASCII"
 
# Cycle through all the child domains in the forest root to query for Group.
foreach ($domain in $forest.Domains)
 {
    $FullGroupName = $domain.name + "\" + $GroupName
    get-allmembers -ObjectName $FullGroupName -OF $of -GN $FullGroupName
}