What type of firewall inspects packets and determines whether they are allowed based on pre-established rules?

A packet filtering firewall inspects individual packets in the network and allows or blocks them based on predefined security rules. This type of firewall operates at the network layer and evaluates packets against a set of criteria, such as source and destination IP addresses, port numbers, and protocols. If a packet matches the criteria defined in the rules, it is allowed through; otherwise, it is dropped. Packet filtering is a fundamental security mechanism, offering a basic level of protection while allowing for high-speed traffic processing. However, it does not maintain the state of connections, which limits its ability to analyze traffic behavior compared to more advanced firewall types. Why Other Options are Wrong: A) A proxy firewall acts as an intermediary between users and the Internet, filtering requests and responses, which is more complex than simple packet filtering. B) A stateful inspection firewall keeps track of active connections and makes decisions based on the state of those connections, providing more sophisticated protection than basic packet filtering. D) Next-generation firewalls incorporate features like application awareness, intrusion detection, and advanced threat protection, going beyond packet filtering capabilities. E) An application firewall operates at the application layer and can inspect traffic for specific applications, not just packet headers.