Which firewall tracks the state of all connections and requests going into and out of the network?

• A. Filtered Router
• B. Stateful Firewall
• C. Proxy Firewall
• D. Kernel Proxy

Answer: (B)

Stateful inspection is the idea here. A stateful firewall keeps a table of active connections and tracks how each packet fits into those connections. It knows whether a packet starts a new connection, belongs to an already established one, or signals the end of a session. Because of this, it can automatically allow return traffic for outbound requests while blocking traffic that isn’t part of a valid, existing connection. This dynamic, context-aware filtering provides stronger protection than one-off, per-packet checks.

Other approaches either inspect packets in isolation without regard to connection context or act as intermediaries at the application level. A simple packet-filtering setup doesn’t track state, and proxy-based firewalls (including kernel proxies) focus on routing or content inspection rather than maintaining per-connection state for all traffic.