Stateful packet inspection firewalls are ________.

• A. Expensive
• B. Fairly safe in practice
• C. Both A and B
• D. Neither A nor B

Answer: (B)

Stateful inspection keeps track of the state of active connections and uses that context to validate each incoming packet. By tying packets to a legitimate, ongoing session, it can distinguish between normal traffic and spoofed or out-of-sequence packets, making it significantly safer in practice than simple stateless filtering. It’s not a perfect shield, though—encrypted payloads aren’t inspected beyond headers, high-throughput demands can raise costs, and misconfigurations or application-layer attacks can still slip through. So, describing stateful packet inspection firewalls as fairly safe in practice captures their real security benefit without implying absolute protection or universal expense.