网络监听工具，同一网段网卡设为混合模式，当网络中有数据包传输，无论是否属于主机，网卡都会接受该报文，sniff简化版本。-Network monitoring tools, the same LAN segment is set to mixed mode, when the network has data packets, whether belonging to the host, NIC will accept the packet, sniff simplified version.