中文摘要：

网络数据包的捕获、监听与分析技术是网络安全和协议分析的一个基础技术。FTP数据包以明文的形式传输,缺乏访问控制机制可能出现垃圾文件和不雅图片等隐患。针对这些问题,文章是在VC开发环境下,基于WinPcap的监听机在Windows平台上运行监听程序,从网卡捕获网络数据包,对拦截的数据包进行过滤处理,并部署了Web页面和Windows资源管理器两种不同实验的下载环境,分析怎样获取FTP数据及如何还原文件。实验结果表明,该设计的程序完全达到实时性要求,实现了多线程监控及还原FTP上传及下载文件的需求。

英文摘要：

The technology of capturing,monitoring and technology of analyzing is the basis of network＇s maintenance and protocol analysis.Plain in the form of transmission of FTP packets on the net and lack of effective identity authentication will cause rubbish files and inelegancy pictures.According to these problem,this paper base on the package capture technology of WinPcap the monitor computer runs the monitor programs in VC software environment on Windows system,captures data Packets from network card and filters these data packets,and it has disposed two different experimental environments and analyzes how to capture the data of FTP and recovery files.The experiment result indicates that the algorithm can meet the real-time request,realizing multi-thread monitor and recovery the documents of FTP uploading and downloading.