Standardized Security Controls by IETF

C.

The security control standardized by the Internet Engineering Task Force (IETF) as the primary network layer protection mechanism is Internet Protocol Security (IPSec). Therefore, the correct option is C.

IPSec is a security protocol suite used to secure Internet Protocol (IP) communications. It is used to provide encryption, authentication, and data integrity of IP packets in communication between network devices. IPSec is implemented in the network layer of the OSI model, which allows it to operate independently of the applications and the transport layer protocols.

IPSec provides two modes of operation: Transport mode and Tunnel mode. Transport mode is used to secure communication between two hosts, while Tunnel mode is used to secure communication between two networks. IPSec can be used to provide confidentiality, integrity, and authentication for the communication between hosts and networks.

IPSec is standardized by the IETF, which is responsible for the development and promotion of Internet standards. IETF defines the standards for IPSec in a series of Request for Comments (RFC) documents. The standardization of IPSec ensures that it is implemented consistently across different devices and platforms.

In conclusion, IPSec is the security control standardized by the IETF as the primary network layer protection mechanism. Internet Key Exchange (IKE) Protocol, SMIME, and Secure Socket Layer (SSL) are security protocols used in different layers of the OSI model and are not standardized by the IETF as the primary network layer protection mechanism.