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 <tomlobato@xxxxxxxxx> 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 >
