CyberCertPrepNetwork FundamentalsNetwork Security BasicsEASYFree question
Which network security control operates at Layer 3-4 and filters traffic based solely on source IP, destination IP, protocol, and port without tracking connection state?
- A.Stateful inspection firewall
- B.Next-generation firewall (NGFW)
- C.Stateless packet filter (ACL)
- D.Intrusion Prevention System (IPS)
Why C is correct
A stateless packet filter (ACL) evaluates each packet in isolation using Layer 3-4 header fields: source/destination IP, protocol, and ports. It has no memory of prior packets and cannot distinguish a reply packet from an attack. Stateful firewalls (option A) track TCP connection state. NGFWs (option B) add Layer 7 deep packet inspection. IPS (option D) uses signatures and anomaly detection beyond simple header matching.
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