This INTEGER object (enable or disable) indicates whether additional user authentication is required under this FTP policy, beyond whatever authentication the FTP server itself performs. An administrator enables this to force proxy-level authentication before a client can even reach the FTP server, adding a layer of access control at the firewall. For example, setting this to enable(1) for a policy applied to external FTP clients would require them to authenticate at the proxy before their FTP session is relayed inward.