Refer to the exhibit.

With the client attempting an implicit SFTP connection to the SFTP server, which mode
works by default?

A.
passive

B.
neither passive nor active

C.
active

D.
both passive and active

Explanation:
The ASA firewall has issues in regards of handling this type of connections. Normally
when regular FTP is used, the ASA sees the payload on the FTP control channel and doesthe proper NAT translations when using passive mode, when using active, he sees the IP
addresses and let the data connection to be established. On the other hand, since on
the secure methods (FTPS and SFTP), the control channel is encrypted, the ASA has not
way to determine the ports being used .