Passive mode ftp still uses a second connection for data, just the direction of the connection differs.

In normal 'active' ftp, the client connect to remote port 21 for control, and data connections come back from the server with a source port of 20 and destination port > 1024. In 'passive' ftp, the client still connect to remote port 21 for control, however data connections originate _from_ the client on a port > 1024 to the remote server on a port > 1024, thus passing through firewalls that only allow outgoing connections.

Then, of course, is the issue of binary mode encoding, translating between formats, etc... Much easier to use Net::FTP, unless you have a week or so to kill on a 15 minute job. ;-)