If the port number is 990, use implicit SSL (
FtpSecurity.Implicit). If the port number is 21, it's more complicated - it's either non-encrypted connection or it's secured using explicit SSL (
FtpSecurity.Explicit). If unsure, establish a non-encrypted connection first and try to enable explicit SSL later by calling
Secure method (if it throwns an
FtpException, it means that explicit SSL is not possible, but you can still continue using the connection in standard non-encrypted mode.
(Finally, if the port number is 22, you need to use Rebex SFTP instead of Rebex FTP/SSL.)