What captures network packets and is typically integrated with a protocol analyzer?

The correct answer is a sniffer, which is a tool designed to capture and analyze network packets as they travel across a network. When integrated with a protocol analyzer, a sniffer enables users to inspect packet contents, understand network traffic patterns, and troubleshoot network issues.

It works by putting the network interface card (NIC) into a mode that allows it to intercept and log all traffic passing through the network segment, regardless of the destination. The information gathered can include metadata like source and destination IP addresses, protocol information, and sometimes even the actual data payload.

While firewalls, switches, and routers have their respective roles in managing and directing network traffic, they do not primarily focus on capturing packets for analysis. A firewall is more about controlling access and preventing unauthorized entry, a switch connects devices on a local network segment and manages data traffic between them, and a router directs data packets between different networks. None of these devices are specifically designed for the detailed capture and analysis of network packets like a sniffer is.