What key feature distinguishes a stateful firewall from other types of firewalls?

The key feature that distinguishes a stateful firewall from other types of firewalls is its ability to maintain the state of active connections. This means that a stateful firewall keeps track of the ongoing connections and the state of those connections, allowing it to make more informed decisions about which packets to allow or deny based on the context of the traffic.

Unlike stateless firewalls, which treat each packet in isolation and apply filtering rules without considering the state of the traffic, stateful firewalls can recognize whether a packet is part of an existing connection or a new request. This context-awareness enhances security by enabling more complex filtering rules, such as allowing inbound traffic only if it is part of an established connection.

Other options like analyzing traffic based on rules or using packet filtering are features that may be found in various types of firewalls, not just stateful ones. Also, firewall configuration is typically necessary for all types of firewalls, making the assertion that it does not require configuration inaccurate. Thus, the ability to maintain the state of connections sets stateful firewalls apart.