(Sniffer software is a powerful protocol analysis software launched by NAI, which has the functions of capturing network traffic for detailed analysis, monitoring network flow in real time, diagnosing problems using expert analysis systems, and collecting network utilization and errors. SnifferPro4.6 can run on various Windows platforms, just install it on any machine in the network, it can monitor the overall network. The following takes the Chinese version of Sniffer 4.7.5 as an example to introduce the detailed use of Snffer in LAN protection.)