CISSP Practice Exam 2025 – Complete Prep Guide

A MAC address, or Media Access Control address, is indeed a unique identifier assigned to network interfaces for communications on a physical network segment. It is utilized primarily within Layer 2 of the OSI model, which is known as the Data Link layer. Each network interface card (NIC) has a MAC address hardcoded into it, which serves to identify the device on a local network, enabling devices to communicate with each other within the same physical network.

The importance of a MAC address lies in its role in framing data packets for transmission. When packets are sent over a local area network (LAN), they include the MAC addresses of both the source and destination devices, allowing switches and routers to forward the packets to the correct destination.

The other options provided do not represent the correct function of a MAC address. While a Layer 3 IP address is used to identify devices on a network at a higher level, it is not a unique hardware identifier and operates differently, typically outside of local segment addressing. A data encryption key is related to security and data protection, which is unrelated to the MAC address concept. A firewall configuration pertains to settings that control incoming and outgoing traffic based on predetermined security rules, which does not involve identifying network devices. Thus, the answer accurately