CompTIA Network+ Practice Test

What are Access Control Lists (ACLs) used for?

1. To monitor system performance

2. To determine actions based on specified rules for incoming packets

3. To store network traffic data

4. To limit physical access to devices

The correct answer is: To determine actions based on specified rules for incoming packets

Access Control Lists (ACLs) are primarily utilized to define rules that specify how incoming and outgoing packets should be treated by a network device, such as a router or a firewall. They serve as a filtering mechanism that enables the control of which traffic is permitted or denied based on criteria such as IP address, protocol type, or port number. The correct answer emphasizes that ACLs assess incoming packets against predefined conditions and decide whether to allow or block those packets from passing through the network. This ability to determine actions based on specified rules is fundamental for maintaining security and managing traffic flow in a network. Utilizing ACLs is a crucial element of network management because it allows administrators to enforce policies, restrict access to sensitive areas of the network, and mitigate potential threats by controlling traffic based on established guidelines. This function is vital in protecting network resources from unauthorized access and optimizing overall performance. The other options focus on functions that ACLs do not perform. For instance, monitoring system performance is typically achieved through different tools and metrics, while storing network traffic data is the role of network logging and monitoring systems. Limiting physical access to devices is a separate security concern, often addressed through physical security measures rather than network access controls.