Pasv

$FTP->Pasv([mode])

If called with no arguments, returns 1 if the current FTP session has passive transfer mode enabled; 0 if not. You can call it with a mode parameter (0/1) only as a method of a Internet object, in which case it will set the default value for the next FTP object you create (i.e., set it before, because you can't change this value once you open the FTP session).