(Ntop is a network monitoring tool, namely network sniffer. It can monitor network traffic and even list each section Network bandwidth utilization of point computers. It can determine various problems on the network by analyzing the network traffic; It can also be used to judge whether hackers are attacking the network system; It can also easily display the specific network protocol, the host that occupies a lot of bandwidth, the target host of each communication, the sending time of the data packet, the delay of transmitting the data packet and other details.)