Which firewall combines the features of packet filtering, circuit-level gateways, and application-level firewalls, filtering at the network layer and evaluating contents at the application layer?

Which firewall combines the features of packet filtering, circuit-level gateways, and application-level firewalls, filtering at the network layer and evaluating contents at the application layer?

• A. Packet Filtering Firewall
• B. Stateful Multilayer Inspection Firewalls
• C. NAT
• D. Application-Level Proxy

Answer: (B)

This item tests multi-layer firewall capabilities that combine different inspection techniques into one device. Stateful Multilayer Inspection firewalls integrate packet filtering (checking headers to decide allow/deny), circuit-level gateway behavior (maintaining and validating the state of connections so sessions are legitimate), and application-level inspection (examining the actual data payload at the application layer to enforce policies and detect abuse). They filter at the network layer while also evaluating contents at the application layer, giving protection that spans multiple layers rather than just basic header checks. A simple packet-filtering firewall only looks at headers and offers limited protection; it doesn’t track connection state or inspect payloads. NAT is about translating addresses and ports and doesn’t perform content inspection or layered security. An application-level proxy focuses on proxying at the application layer, often handling specific protocols, but it doesn’t inherently merge the broad network-layer filtering and connection-state tracking across multiple layers that a stateful, multi-layer inspection firewall provides.

This item tests multi-layer firewall capabilities that combine different inspection techniques into one device. Stateful Multilayer Inspection firewalls integrate packet filtering (checking headers to decide allow/deny), circuit-level gateway behavior (maintaining and validating the state of connections so sessions are legitimate), and application-level inspection (examining the actual data payload at the application layer to enforce policies and detect abuse). They filter at the network layer while also evaluating contents at the application layer, giving protection that spans multiple layers rather than just basic header checks.

A simple packet-filtering firewall only looks at headers and offers limited protection; it doesn’t track connection state or inspect payloads. NAT is about translating addresses and ports and doesn’t perform content inspection or layered security. An application-level proxy focuses on proxying at the application layer, often handling specific protocols, but it doesn’t inherently merge the broad network-layer filtering and connection-state tracking across multiple layers that a stateful, multi-layer inspection firewall provides.