I'm trying to make a connection to an external server. The server administrator wants to know how I intend to make an FTP connection (SSH, SSL, etc). I intend to use php's ftp_ssl_connect() function, because the FTP activity is part of a website. I know the external server is CentOS, and I don't really have any other details. Should I just tell him that the connection is plain SSL? Will it still be port 21? The reason why I ask is that my FTP client has multiple encryption options (FTPeS, FTPiS, SFTP), so I just want to be sure that I'm telling him the right thing so I don't waste our employer's time.