What does packet filtering do?

Packet filtering is a network security mechanism that examines and controls the flow of data packets based on specific criteria set by a network administrator. Essentially, it filters traffic by analyzing attributes of each packet, such as the source IP address, destination IP address, port numbers, and protocols. By establishing rules for which packets are allowed or denied entry to the network, packet filtering helps protect the network from unauthorized access or harmful traffic. This method allows for enhanced security and the ability to manage and regulate the types of communication that are permitted.

For instance, if a packet matches a predefined rule that restricts traffic from a certain IP address or port, it can be automatically dropped, preventing potentially malicious data from entering the network. This selective control is critical for maintaining an organization's cybersecurity posture.