Access control lists (ACLs) are a security mechanism used in computer operations to enforce and manage access permissions for users and resources. ACLs enable organizations to control who can access specific data or resources, helping to ensure the confidentiality of sensitive information.

Malware often utilizes encryption techniques to make its communication with command and control servers difficult to detect. Encryption helps in disguising the communication and prevents network security measures from intercepting or analyzing the malicious traffic.

Conducting a post-incident analysis serves the purpose of assessing the overall effectiveness of the incident response plan. It helps identify any weaknesses or areas for improvement in the plan. While identifying responsible individuals, restoring affected systems, and providing management summaries are important aspects, the primary focus of a post-incident analysis is to evaluate and enhance future incident response efforts.

The correct command-line tool for network traffic capture and packet analysis is tcpdump. It captures packets that are transmitted on a network interface, allowing you to analyze the traffic, detect potential security threats, and understand the behavior of network communications.

A firewall is a network security device that monitors and filters network traffic based on a set of predefined rules. It acts as a barrier between an internal network and external networks, allowing or blocking traffic based on specific criteria, such as source IP address, destination port, protocol, etc.