List Exchange Mailbox Permissions

$root = [ADSI]'LDAP://RootDSE' 
$dfDefaultRootPath = "LDAP://" + $root.DefaultNamingContext.tostring()
$dfRoot = [ADSI]$dfDefaultRootPath
$gfGALQueryFilter =  "(&(&(&(mailnickname=*)(objectCategory=person)(objectClass=user))))"
$dfsearcher = new-object System.DirectoryServices.DirectorySearcher($dfRoot)
$dfsearcher.PageSize = 4500
$dfsearcher.Filter = $gfGALQueryFilter
$dfsearcher.PropertiesToLoad.Add("msExchMailboxSecurityDescriptor")
$srSearchResult = $dfsearcher.FindAll()
"Mailbox ACE User"
foreach ($emResult in $srSearchResult) {
 $uoUserobject = New-Object System.DirectoryServices.directoryentry
 $uoUserobject = $emResult.GetDirectoryEntry()
 $emProps = $emResult.Properties
 [byte[]]$DaclByte = $emProps["msexchmailboxsecuritydescriptor"][0]
 $adDACL = new-object System.DirectoryServices.ActiveDirectorySecurity
 $adDACL.SetSecurityDescriptorBinaryForm($DaclByte)
 $mbRightsacls =$adDACL.GetAccessRules($true, $false, [System.Security.Principal.SecurityIdentifier])
 foreach ($ace in $mbRightsacls){
  if($ace.IdentityReference.Value -ne "S-1-5-10" -band $ace.IdentityReference.Value -ne "S-1-5-18" -band $ace.IsInherited -ne $true){  
    $sidbind = "LDAP://"
    $AceName = $ace.IdentityReference.Value 
           $aceuser = [ADSI]$sidbind
    if ($aceuser.name -ne $null){
     $AceName = $aceuser.samaccountname
    }

    "" + $uoUserobject.DisplayName  + " " +  $AceName
  }
 }
}