Final answer:
At the perimeter layer of a network, multiple security controls can be applied, including firewalls to control traffic, intrusion prevention systems to monitor and block malicious activity, and access control lists to specify permissions. The correct answer is D. All of the above.
Step-by-step explanation:
Security Controls at the Perimeter Layer
When considering security controls that can be applied at the perimeter layer of a network, there are several key measures that can be implemented. These include:
Firewalls: They serve as a barrier between trusted and untrusted networks, controlling incoming and outgoing network traffic based on an applied rule set.
Intrusion Prevention Systems (IPS): These systems monitor network and/or system activities for malicious activity. The primary function of an IPS is to identify suspicious activity, log information about this activity, attempt to block it, and report it.
Access Control Lists (ACLs): ACLs provide a list of permissions attached to an object. They specify which users or system processes are granted access to objects, as well as what operations are allowed on given objects.
The correct answer to the question of which security controls can be applied at the Perimeter layer would be D. All of the above. Each of these measures serves to protect network perimeters from unauthorized access and potential breaches.