Data classification is necessary to define access rules based on a need-to-do and need-to-know basis. The data owner is responsible for defining the access rules; therefore, establishing ownership is the first step in data classification. The other choices are incorrect. A criticality analysis is required for protection of data, which takes input from data classification. Access definition is complete after data classification and input for a data dictionary is prepared from the data classification process.

Explanation
When implementing Internet Protocol security (IPsec) architecture, the servers involved in application delivery communicate via Transport Layer Security (TLS), which is a protocol that provides encryption and authentication for data transmitted over a network. IPsec operates at the network layer and provides security for IP packets, while TLS operates at the transport layer and provides security for TCP connections. Blocking authorized users from unauthorized activities, channeling access only through the public-facing firewall, and channeling access through authentication are not functions of IPsec architecture. References: CISA Review Manual (Digital Version), Chapter 5, Section 5.4.2

Stopping the service and installing the security fix is the safest way to prevent the worm from spreading, if the service is not stopped, installing the fix is not the most effective method because the worm continues spreading until the fix becomes effective. Blocking the protocol on the perimeter does not stop the worm from spreading to the internal network(s). Blocking the protocol helps to slow down the spreading but also prohibits any software that utilizes it from working between segments.