I have an Ubuntu 16.04 instance that seems to not have FTP installed, but I can use WinSCP to connect from my local pc to the instance using protocol SFTP on port 22, and then I can download files from the instance to my local pc.
The instance doesn't seem to have any kind of FTP server installed, and all incoming ports are blocked other than 22 and 443. Does this mean that an FTP server is not required for SFTP? Is this the same for FTPS?
I can download files, but I can't upload. I get the error message "Cannot create remote file '...'. Permission denied. Error code: 3 Error message from server: Permission denied" - without any FTP server (or FTP server config files) installed, what is allowing me to download but preventing me from uploading?
I understand FTPS uses an SSL certificate, so I assume FTPS is the preferred choice over SFTP, is this right?