Next-Generation Firewalls (NGFW) primarily belong to which generation of…

Correct answer: Third Generation Firewall.

Firewall technology is commonly grouped into generations. First-generation firewalls are packet-filtering firewalls that inspect each packet's header (IP addresses, ports, protocol) in isolation. Second-generation firewalls add stateful inspection, tracking the state of active connections so packets are evaluated in the context of an ongoing session.

A Next-Generation Firewall (NGFW) belongs to the third generation of firewall technology. The term was popularised by Gartner. An NGFW combines a traditional (stateful) firewall with additional application-aware capabilities such as in-line deep packet inspection (DPI), an integrated intrusion prevention system (IPS), application-level traffic control, and often TLS/SSL inspection and user-identity integration. This deeper, application-layer inspection is what distinguishes the third generation from the port/protocol filtering of the first two generations.

Therefore, NGFWs are classified as Third Generation Firewalls.