What is the main purpose of an egress filter?

The main purpose of an egress filter is to control and monitor outbound traffic from a network. Egress filtering allows network administrators to enforce security policies by restricting which traffic can leave the network based on predefined rules. This is crucial for preventing sensitive data from being exfiltrated and stopping potentially malicious traffic from leaving the network.

By implementing egress filtering, organizations can effectively manage their data flows and protect against various threats, such as data breaches or unauthorized communications. This outbound control helps in maintaining the integrity and confidentiality of sensitive information, ensuring that only approved data is transmitted outside the network perimeter.

Other options do not align with the primary function of an egress filter. For instance, filtering based on user authentication pertains more to access controls rather than monitoring outbound traffic itself. Similarly, prioritizing live communication deals with quality of service rather than traffic filtering, and categorizing traffic based on content types refers to traffic classification rather than the management of outbound flows. Thus, the focus of an egress filter is distinct and specific to controlling outbound network traffic.