A specialized hardware device or software in a desktop or laptop computer that captures packets transmitted in a network for routine inspection and problem detection. Also called a "sniffer," "packet sniffer," "packet analyzer," "traffic analyzer" and "protocol analyzer," the network analyzer plugs into a port on a network hub or switch and decodes one or more protocols into a human-readable format for the network administrator. It can also store packets on disk for further analysis later on.|
Network analyzers can also analyze the packets in real time in order to alert the administrator about problems. Hardware network analyzers can detect voltage and cable problems, which software-only analyzers cannot. See port mirroring.