实验7 使用Etereal观察ping命令的工作过程.doc

使用Ethereal观察ping命令的工作过程 ?实验目的： 了解嗅探器工具Ethereal的下载和安装方法； 掌握Ethereal的简单使用方法； 了解抓包结果的分析方法。 实验步骤： 复习与ping命令相关的因特网控制报文协议ICMP相关的内容，通过有哪些信誉好的足球投注网站引擎了解什么是嗅探器。 1自己下载安装并启动Ethereal； 2 打开命令提示符窗口，准备输入要运行的ping命令； 3 单击“Capture”菜单中的“Start”菜单项开始抓包； 4 输入要运行的pjng命令及要测试的目标主机的ip地址，等到ping命令的结果完全显示出来后，单击软件中的stop按钮，停止包的抓获； 5 在Ethereal的显示过滤器输入栏中输入“icmp”这时界面上将显示所有包含有Icmp协议的报文段。单击选中相应的数据包，在树形视图面板中看它各层协议首部的详细信息。 6 针对运行结果，深入思考icmp协议的重要作用以及连通测试工具ping的实现原理。 问题思考： 1 Ethereal是一款什么样的软件，有什么作用？ 2试说明连通测试工具ping的实现原理。实验背景知识 / Description WinPcap is the industry-standard tool for link-layer network access in Windows environments: it allows applications to capture and transmit network packets bypassing the protocol stack, and has additional useful features, including kernel-level packet filtering, a network statistics engine and support for remote packet capture. WinPcap consists of a driver, that extends the operating system to provide low-level network access, and a library that is used to easily access the low-level network layers. This library also contains the Windows version of the well known libpcap Unix API. Thanks to its set of features, WinPcap is the packet capture and filtering engine of many open source and commercial network tools, including protocol analyzers, network monitors, network intrusion detection systems, sniffers, traffic generators and network testers. Some of these tools, like Wireshark, Nmap, Snort, ntop are known and used throughout the networking community. W is also the home of WinDump, the Windows version of the popular tcpdump tool. WinDump can be used to watch, diagnose and save to disk network traffic according to various complex rules. / Powerful Multi-Platform Analysis Ethereal? is used by network professionals around the world for troubleshooting, analysis, software and protocol development, and education. It has all of the standard features you would expect in a protocol analyzer, and several features not seen in any other product. Its open source license allows talented exper