Communication between an ONTAP system and an external FPolicy server occurs over a TCP/IP connection. ONTAP acts as the client, initiating the connection to the FPolicy server. While the specific port number is configurable when creating the external engine definition on ONTAP (vserver fpolicy external-engine create -port ), the underlying transport protocol is TCP. This ensures reliable, ordered delivery of file access notifications and policy responses, which is critical for making real-time access decisions. Option B correctly identifies TCP as the protocol.

A. NFS is a file sharing protocol used for client access to data, not for the FPolicy control plane communication between ONTAP and a policy server.

C. HTTPS is not the native protocol for FPolicy. The communication uses a proprietary XML-based payload over a standard TCP socket, not HTTP encapsulated in TLS.

D. UDP is a connectionless protocol and is not used for FPolicy, which requires the reliable, stateful communication provided by TCP to ensure notifications are received and acted upon.

NetApp ONTAP 9 Documentation Center. (2023). File access and protocols management guide for ONTAP 9.10.1. "How FPolicy works". The documentation describes the communication as occurring over a "TCP/IP connection."

NetApp ONTAP 9 Documentation Center. (2023). Command Reference for ONTAP 9.10.1. "vserver fpolicy external-engine create". The command parameters include -port and -server , which define the TCP port and IP address of the FPolicy server.