What software uses what FTP mode?
It is up to the client to decide what mode to use; the default mode when a new connection is opened is “active mode”. Most FTP clients come preconfigured to use active mode, but provide an option to use “passive” (“PASV”) mode. An exception is the windows command line FTP client which only operates in active mode. Web Browsers generally use passive mode when connecting via FTP, with a weird exception: MSIE 5 will use active FTP when FTP:ing in “File Explorer” mode and passive FTP when FTP:ing in “Web Page” mode. There is no reason whatsoever for this behaviour; my guess is that someone in Redmond with no knowledge of FTP decided that “Of course we’ll use active mode when we’re in file explorer mode, since that looks more active than a web page”. Go figure.
It is up to the client to decide what mode to use; the default mode when a new connection is opened is “active mode”. Most FTP clients come preconfigured to use active mode, but provide an option to use “passive” (“PASV”) mode. An exception is the windows command line FTP client which only operates in active mode. Web Browsers generally use passive mode when connecting via FTP, with a weird exception: MSIE 5 will use active FTP when FTP:ing in “File Explorer” mode and passive FTP when FTP:ing in “Web Page” mode. There is no reason whatsoever for this behaviour; my guess is that someone in Redmond with no knowledge of FTP decided that “Of course we’ll use active mode when we’re in file explorer mode, since that looks more active than a web page”. Go figure.
