Something that isn't mentioned above is that although ftp_ssl_connect may be available and will return an FTP stream it may not be usable. Take the following code (FTP login credentials are obviously set elsewhere):
$ftp_connection = @ftp_ssl_connect($this->ftp_host);
$ftp_connection = @ftp_connect($this->ftp_host);
ftp_login($ftp_connection, $this->ftp_user, $this->ftp_password);
// output: bool(true) resource(71) of type (FTP Buffer)
From this you'd assume everything would work, ftp_ssl_connect is available and you have a connection. However, once you get to ftp_login, you could get this:
Warning  ftp_login() [function.ftp-login]: AUTH not understood
This is because the server is not configured to understand the encrypted details, even though the function is available and an SSL-FTP stream was opened.
If you are trying to use ftp_ssl_connect make sure you check if you can login after using it, and if not, connect again with standard ftp_connect.
Hope this is of use.
(PHP 4 >= 4.3.0, PHP 5)
ftp_ssl_connect — Opens an Secure SSL-FTP connection
ftp_ssl_connect() opens an explicit SSL-FTP connection to the specified host.
Note: Why this function may not exist
ftp_ssl_connect() is only available if both the ftp module and the OpenSSL support is built statically into php, this means that on Windows this function will be undefined in the official PHP builds. To make this function available on Windows you must compile your own PHP binaries.
ftp_ssl_connect() is not intended for use with sFTP. To use sFTP with PHP, please see ssh2_sftp().
The FTP server address. This parameter shouldn't have any trailing slashes and shouldn't be prefixed with ftp://.
This parameter specifies an alternate port to connect to. If it is omitted or set to zero, then the default FTP port, 21, will be used.
This parameter specifies the timeout for all subsequent network operations. If omitted, the default value is 90 seconds. The timeout can be changed and queried at any time with ftp_set_option() and ftp_get_option().
Returns a SSL-FTP stream on success or FALSE on error.
|5.2.2||The function was changed to return FALSE when it can't use an SSL connection, instead of fallbacking to a non-SSL one as previously.|
Example #1 ftp_ssl_connect() example
// set up basic ssl connection
$conn_id = ftp_ssl_connect($ftp_server);
// login with username and password
$login_result = ftp_login($conn_id, $ftp_user_name, $ftp_user_pass);
echo ftp_pwd($conn_id); // /
// close the ssl connection
- ftp_connect() - Opens an FTP connection