This read-only property shows if the SFTP tunnel has been created and object methods are ready to be called.
If this property value is
True, the SFTP tunnel has been created, and the component can send and receive data.
If the property is set to
False, the SFTP tunnel has not be created.
However, if the connection is lost on the socket level, there is no way to find out that the connection has been closed, and Active property can still be True. The only way to check the actual connection state is to send something and get an error if the connection has been closed. This is by design of TCP/IP.
Your code should always be ready to handle unexpected disconnections and other network errors and reconnect if needed.