FTP has become complicated. These are two standards for secure ftp
SFTP and FTPS.

SFTP operates like ssh/scp. It uses the same port (port 22). openssh
supports sftp both client and server.

FTPS operates like ftp and ssl/tls (port 20/21, etc). Among the ftp
clients that now support this addition are gftp and fireftp. vsftpd is
a FTPS server.

On Wed, Mar 5, 2008 at 9:29 PM, Tom Lobato wrote:
> Bob Rasmussen escreveu:
>
> > In the FTP protocol, "passive" means that only one connection is
> > established, originating in the client. All trafic goes over this
> > connection. (In non-passive FTP, the server opens a second channel back to
> > the client.)
> >
> > No such differentiation exists in SFTP. There is only one connection.
> >
> > The vendor may be using "passive" in a different sense, but I don't think
> > it is a widely accepted usage.

>
> in really, both passive and active ftp modes uses two connections. The
> first, which is originated on client (to port 21 on server), is the
> control connection, for authentication, command/response exchanges, etc.
> The second connection, which transfer effective data, support two modes:
> passive: originated from client to server. Uses destination port
> defined on control connection.
> active: originated from server to client. Uses destination port 20 on
> client.
>
> See http://www.faqs.org/rfcs/rfc1579.html (Firewall-Friendly FTP).
>
> good resources:
> http://en.wikipedia.org/wiki/File_Transfer_Protocol
> http://www.slacksite.com/other/ftp.html
> http://www.faqs.org/rfcs/rfc959.html (for the braves!)
>
>
> Tom Lobato
> www.tinecon.com.br
>