Data ONTAP supports Server Message Block (SMB) signing when requested by the client. You can enable SMB signing on the storage system. By default, SMB signing is disabled.
SMB signing helps to ensure that network traffic between the storage system and the client has not been compromised by ensuring that all SMB messages have valid signatures. When SMB signing is enabled on the storage system, it is the equivalent of the Microsoft Network server policy "Digitally sign communications (if client agrees)".
If this option is enabled, then the storage system does the following:
If the client cannot establish an SMB 2.x session with signing, the client falls back to an SMB session with or without signing, and the storage system uses whichever the client requests.
See the cifs terminate man page for more information.