# This Perl code will print the global catalog servers for the specified forest.

# ---------------------------------------------------------------
# Adapted from VBScript code contained in the book:
#      "Active Directory Cookbook" by Robbie Allen
# Publisher: O'Reilly and Associates
# ISBN: 0-596-00466-4
# Book web site: http://rallenhome.com/books/adcookbook/code.html
# ---------------------------------------------------------------

# ------ SCRIPT CONFIGURATION ------
my $strForestName = "<ForestDNSName>";  # e.g. rallencorp.com
# ------ END CONFIGURATION ---------
use Win32::OLE;
$Win32::OLE::Warn = 3;
my $objRootDSE = Win32::OLE->GetObject("LDAP://" . $strForestName . "/RootDSE");
my $strADsPath = "<LDAP://" . $objRootDSE->Get("configurationNamingContext") . ">;";
my $strFilter  = "(&(objectcategory=ntdsdsa)(options=1));";
my $strAttrs   = "distinguishedname;";
my $strScope   = "SubTree";

my $objConn = Win32::OLE->CreateObject("ADODB.Connection");
$objConn->{Provider} = "ADsDSOObject";
$objConn->Open;
my $objRS = $objConn->Execute($strADsPath . $strFilter . $strAttrs . $strScope);
$objRS->MoveFirst;
while (not $objRS->EOF) {
    my $objNTDS = Win32::OLE->GetObject("LDAP://" . $objRS->Fields(0)->Value);
    my $objServer = Win32::OLE->GetObject($objNTDS->Parent);
    print $objServer->Get("dNSHostName"),"\n";
    $objRS->MoveNext;
}