邮件监控SMTPPOP3系统设计与实现(含源文件).doc

I -摘 要本论文主要研究了使用 LIBNIDS 网络安全开发包对邮件客户端收发的邮件的还原邮件客户端收发邮件时涉及到的协议是 SMTP 协议和 POP3 协议利用 LIBNIDS 网络安全开发包对邮件的数据包进行捕获，实现了邮件发件人、收件人、抄送人、收发日期、邮件主题、邮件内容和邮件的附件名称信息的提取在对邮件的各字段进行还原的过程中，对 SMTP 和 POP3 进行协议分析，使用捕获到的 SMTP 协议和 POP3 协议邮件的数据包中的内容，分析了邮件的发送和接收时各字段所在的位置和对应的格式对于含有汉字的字段，如发件人、收件人、抄送人、主题、内容和附件名的还原，也利用分析出的邮件各字段数据格式，设计出汉字还原的方法在此基础上，实现了邮件监视端软件的编写，利用互联网信息服务（IIS ）浏览被监视计算机中的邮件日志文件，实现了邮件监控子系统中监视邮件收发情况的功能关键词　网络监控；邮件监控；邮件还原；SMTP；POP3- II -AbstractThis thesis mainly focused on the restoration for the e-mail client to send or receive e-mails using the development package of network security LIBNIDS. E-mail client to send and received e-mails related to SMTP and POP3 protocol. Making use of LIBNIDS to capture the packets of e-mails, it’s achieved the restoration of main information in e-mails, including the sender, recipient, carbon copy (cc), date, subject, content and attachment name.In the process of restoring e-mails, it carried out on the SMTP and POP3 protocol analysis. With the content of e-mails captured based on SMTP and POP3 protocol, we have analyzed the format for corresponding field in e-mail. While the field contains characters, such as sender, recipient, cc, subject, content and attachment name we also analyzed the format for corresponding field and designed the means to restore Chinese characters.Using of the Internet Information Services (IIS) on this basis, it’s achieved the function of monitoring the situation to send and receive e-mails in the subsystem of e-mail monitoring.Key words network monitoring e-mail monitoring e-mail restoration SMTP POP3- III -目 录摘 要 ...........................................................................................................................IAbstract ........................................................................................................................II第 1 章 绪论 ................................................................................................................11.1 课题背景 ...........................................................................................................11.2 课题来源、目的和意义 ...................................................................................11.2.1 国外研究现状 ............................................................................................11.2.2 国内研究现状 ............................................................................................21.3 主要研究内容 ...................................................................................................21.3.1 邮件监控 ....................................................................................................21.3.2 监控端软件 ................................................................................................31.4 本文结构 ...........................................................................................................3第 2 章 理论基础 ........................................................................................................42.1 引言 ...................................................................................................................42.2 SMTP 协议和 POP3 协议 ..................................................................................42.2.1 SMTP 协议简介 ..........................................................................................42.2.2 POP3 协议简介 ...........................................................................................62.3 LIBNIDS 开发包 ................................................................................................72.3.1 LIBNIDS 简介 .............................................................................................72.3.2 LIBNIDS 数据结构 .....................................................................................92.3.3 LIBNIDS 基本函数 ...................................................................................112.3.4 LIBNIDS 的使用 .......................................................................................122.4 BASE64 简介 ...................................................................................................132.5 本章小结 .........................................................................................................13第 3 章 邮件监控子系统构成和框架 ......................................................................143.1 引言 .................................................................................................................143.2 模块组成 .........................................................................................................143.3 运行框架 .........................................................................................................173.4 本章小结 .........................................................................................................18第 4 章 基于 SMTP 和 POP3 协议的邮件还原 .......................................................19- IV -4.1 引言 .................................................................................................................194.2 总流程 ....................。