Description:
------------
I'm trying to connect to FTP server from a script.
Script is behind firewall.
Only FTP port is allowed (application/script is to be used in PCIDSS enviroment).

We tried same script on other servers and no problem accured at all. This could be a firewall / web application firewall (mod_security) issue but we're not sure.

Reproduce code:
---------------
$ftp_array = array(
 // Host, user, pass
);

$port = 21;
$network_timeout = 30;

echo "Connecting...\n";

// Connect
$ftp_connection = ftp_connect($ftp_array['host'], $port, network);

if ($ftp_connection) {
	
	// Login
	if ($login = ftp_login($ftp_connection, $ftp_array['user'], $ftp_array['pass'])) {
		// Pasive mode
		ftp_pasv($ftp_connection, true);
		// Change dir
		ftp_chdir($ftp_connection, "in");
		// Get dir listing
		$contents = ftp_nlist($ftp_connection, ".");
		// Echo list
		echo '<pre>';
		print_r($contents);
		echo '</pre>';
	} else {
          
          echo "Can't login to remote server.";

        }
	
	ftp_close($ftp_connection);
	
} else {
  
  exit("Can't connect to remote server.");

}

Expected result:
----------------
Array
(
    [0] => .
    [1] => ..
    [2] => 11829_RATE_39.txt
)


Actual result:
--------------
Warning: ftp_nlist() [function.ftp-nlist]: php_connect_nonb() failed: Operation now in progress (115) in /var/www/html/public_html/ftp_test.php on line 30