以命令形式运行：scanhost Start_IP End_IP.发现网络中的活动主机,编制程序，通过使用ICMP协议的回送请求和回送应答报文，确定指定网段中的活动主机. -To run the command form: scanhost Start_IP End_IP. Found that the activities of the network host, the preparation of procedures, by using ICMP protocol loopback