What type of firewall function does the term 'stateful' refer to?

The term 'stateful' in the context of firewalls refers to the capability of the firewall to maintain information about active sessions. This means that a stateful firewall can track the state of active connections and make intelligent decisions based on the context of the traffic. It records attributes of the ongoing connections, such as the source and destination IP addresses, ports, and the current state of the connection (e.g., established, new, or related).

This ability allows stateful firewalls to offer more robust security than stateless firewalls, which treat each packet in isolation without considering the context of established connections. By keeping track of active sessions, stateful firewalls can enforce security policies and make more informed decisions about whether to allow or block traffic based on the state of the session, thus enhancing the overall security posture of the network.