An IT administrator at a national logistics firm is auditing the company's network protection methods to mitigate vulnerabilities. To prevent unauthorised external packets from entering the corporate LAN while allowing internal users to establish connections with external web servers, the administrator deploys a stateful packet inspection (SPI) firewall.
Which statement correctly describes how a stateful packet inspection firewall operates to provide this protection?
It inspects the actual data payload of each packet against a database of known malware signatures before routing.
It monitors the context of network connections, tracking the state of active sessions to allow incoming packets only if they match an established, legitimate outbound request.
It acts as an intermediary server that terminates the connection, replaces the source IP address with its own, and performs deep content caching.
It dynamically encrypts the headers of all outbound IP packets using a symmetric session key to prevent eavesdropping by external nodes.