Certain packages are offered in client-only and client-server variants. These are SSLBlackbox, SSHBlackbox, and SFTPBlackbox. The client-only packages include the components that implement only the client side of the corresponding protocols. The client-server packages include the components suitable for both the client side and server side of the communication.

The client-only package can be used in a server environment as long as the server acts as a client when using the selected protocol. For example, you can use the SFTPBlackbox client-only package to transmit the files from your server to some remote server, as long as your server initiates the SFTP connection and acts as an SSH/SFTP client.

See the following scheme for an explanation: