E-mail邮件结构分析及其在邮件筛选中的应用

随着现代通信技术的发展,电子邮件成为最快捷、经济的通信手段.但是许多无用、有害的信息随之而来,需要对获得的邮件进行自动的筛选.在邮件的筛选中,对原始邮件的预处理过程(即邮件内容的提取)是一切邮件筛选技术的基础.本文在介绍RFC822、MIME规范的基础上,开发出了一个实用的邮件预处理系统,该系统在信体和信头的边界确定、附件处理、信体内容提取等方面进行了一定的改进,试验证明改进的方法在减少乱码、正确还原邮件以及降低处理维数等方面效果明显.     

基于Linux防火墙的内部邮件监控系统

给出了一种分布式邮件监控系统的设计和实现方案.该方案的实现建立在Linux防火墙的基础上.采用了Netfilter构架中的ip queue机制获取流经网关的邮件,根据SMTP和POP3的协议特点提取邮件内容,利用文本分类技术对邮件内容进行监控.系统中广泛地使用了插件机制,明确地划分了实时处理和离线分析两大类操作的界限.针对文本分类器的特点,系统定义了简明的接口,使不同算法的分类器可以方便地整合到系统当中来.该方案的实施可以有效地监控流经网关的邮件.     

邮件监听与阻断系统研究

文章给出了一种邮件监听与阻断系统的实现方案。在给出系统的体系结构的基础上,介绍了有效发现特定电子邮件的方法,基于文本论点倾向判别的邮件内容分析以及用于网络监控的可靠阻断技术,该系统在10/100M局域网环境下调试通过。     

E-mail邮件结构分析及其在邮件筛选中的应用

随着现代通信技术的发展,电子邮件成为最快捷、经济的通信手段。但是许多无用、有害的信息随之而来,需要对获得的邮件进行自动的筛选。在邮件的筛选中,对原始邮件的预处理过程(即邮件内容的提取)是一切邮件筛选技术的基础。本文在介绍RFC822、MIME规范的基础上,开发出了一个实用的邮件预处理系统,该系统在信体和信头的边界确定、附件处理、信体内容提取等方面进行了一定的改进,试验证明改进的方法在减少乱码、正确还原邮件以及降低处理维数等方面效果明显。     

基于SMTP的网络电子邮件解析设计与实现

本文通过研究用来传递电子邮件的SMTP协议的会话过程和基本原理,引入Libnids网络开发包作为工具,捕获局域网的数据包并进行协议还原和协议分析,从而为邮件内容还原打下基础,以实现系统安全性的提升。     

基于GPRS的嵌入式系统远程监控和升级

针对工作于偏远地区的数据采集嵌入式系统的监测维护和软件升级问题,提出了一种基于GPRS网络的嵌入式系统远程监控和软件升级方案。方案由ARM和DSP为核心组成嵌入式系统,以电子邮件为载体,通过系统对邮件的读取和发送,实现远程监控系统和升级DSP程序。实践表明,该设计方案具有远程监控稳定性高、可靠性强的特点。     

邮件审计系统的设计与实现

针对目前邮件通信的安全问题,在深入研究邮件协议的基础上,提出一种基于libnids动态库的邮件监控系统的设计方案。文中对系统中涉及的几个关键技术进行深入阐述,实现了局域网内邮件的监控还原、关键词审计等功能。最后对系统的性能进行测试,测试结果表明该系统的监控效果能为网络管理部门提供一个高效的邮件监管平台。     

基于MOSS的安全Web电子邮件客户端的设计与实现

MOSS安全电子邮件协议提供对MIME对象进行数字签名和数据加密的服务。本文基于MOSS协议设计实现了一个Web安全电子邮件客户端系统,描述了系统结构、邮件发送和邮件接收的全过程,重点分析了MOSS协议的数字签名和数据加密服务在系统中的设计与实现。     

PDA电子邮件收发系统编码与解码的设计与实现

该文将讲述描绘电子邮件核心结构的RFC822和RFC1521这两个协议,并利用这两个协议设计与实现了PDA电子邮件收发系统的邮件解码与编码,并对系统的未来发展进行展望。     

用电子邮件实现报表数据的传送

本文针对邮政局报刊发行报表处理系统开发的实际问题，分析了数据报表传送的特点，提出了用电子邮件实现数据传送的思路，并给出了用电子邮件实现数据传送的思路，并给出了在Ｄｅｌｐｈｉ５中一切邮件程序的方法。     

无线局域网背景下的电子邮件监控系统研究

针对IEEE802.11无线局域网中存在的安全漏洞,本文研究并设计基于Microsoft Visual C++6.0平台的电子邮件监听系统。监听系统分为无线网络报文监听、报文处理和电子邮件原始信息解析三个部分,并分别进行设计。重点研究报文截获后的处理,提出基于协议过滤、端口序号过滤和时间控制规则的三重过滤机制,大大提高了报文过滤的准确率,保证系统所获得的邮件原始信息的完整性和准确性。实验结果证明,该系统能够对无线局域网背景下的电子邮件进行实时监控和管理。     

Targeting spam control on middleboxes: Spam detection based on layer-3 e-mail content classification

This paper proposes a spam detection technique, at the packet level (layer 3), based on classification of e-mail contents. Our proposal targets spam control implementations on middleboxes. E-mails are first pre-classified (pre-detected) for spam on a per-packet basis, without the need for reassembly. This, in turn, allows fast e-mail class estimation (spam detection) at receiving e-mail servers to support more effective spam handling on both inbound and outbound (relayed) e-mails. In this paper, the naïve Bayes classification technique is adapted to support both pre-classification and fast e-mail class estimation, on a per-packet basis. We focus on evaluating the accuracy of spam detection at layer 3, considering the constraints on processing byte-streams over the network, including packet re-ordering, fragmentation, overlapped bytes, and different packet sizes. Results show that the proposed layer-3 classification technique gives less than 0.5% false positive, which approximately equals the performance attained at layer 7. This shows that classifying e-mails at the packet level could differentiate non-spam from spam with high confidence for a viable spam control implementation on middleboxes.     

大型SMTP服务器的设计与实现

给出了一种大型SMTP服务器系统的分布式结构、SMTP服务器扩展的方法以及MIME格式的电子邮件解析方式，同时给出了邮件的存储方式、邮件列表的结构和邮件列表的处理方式以及系统核心模块的实现代码。在系统实现中采用了面向对象技术和多线程技术，系统完全由标准C 语言实现。该SMTP系统适于大型电子邮件系统应用，它能够同时处理大量并发邮件操作，运行在各种操作系统与硬件平台上。     

An intelligent method to block e-mail bombs

It is hard to block e-mail bombs because they are usually sent by normal SMTP (Simple Mail Transfer Protocol) applications with fake mail sender addresses and IP addresses. Fortunately, original network packets contain real IP address information anyway. Collecting and analyzing these packet contents can help an administrator to realize where the e-mail bombs are coming from and block them. This article presents a simple method that uses a bandwidth manager device to collect and analyze packets to get e-mail bombs information as well as to block e-mail bomb source IP addresses in routers. In practical application experiences at the computer center in a university, this method blocked e-mail bombs simply and effectively. Furthermore, a fuzzy inference system was also designed to help identify e-mail bombs. Its fuzzy membership functions could be adapted using the fuzzy neural network learning method. In brief, the proposed method affords an automatic and adaptable alarm to find e-mail bombs.     

Moodle及邮件系统基于LDAP的统一身份认证

Moodle和邮件系统是两个既相关又独立的应用系统,它们有各自的认证体系。在校园应用环境下,如何实现两者的统一认证和管理,这是在工作实际中遇到的一个问题。通过对两个系统的认证方式的认识和了解,从轻量级目录访问协议LDAP的数据模型入手,着重讨论LDAP服务器的配置以及作为客户端的Moodle与邮件系统的LDAP配置过程。     

Speech-based interaction with in-vehicle computers: the effect of speech-based e-mail on drivers' attention to the roadway

As computer applications for cars emerge, a speech-based interface offers an appealing alternative to the visually demanding direct manipulation interface. However, speech-based systems may pose cognitive demands that could undermine driving safety. This study used a car-following task to evaluate how a speech-based e-mail system affects drivers' response to the periodic braking of a lead vehicle. The study included 24 drivers between the ages of 18 and 24 years. A baseline condition with no e-mail system was compared with a simple and a complex e-mail system in both simple and complex driving environments. The results show a 30% (310 ms) increase in reaction time when the speech-based system is used. Subjective workload ratings and probe questions also indicate that speech-based interaction introduces a significant cognitive load, which was highest for the complex e-mail system. These data show that a speech-based interface is not a panacea that eliminates the potential distraction of in-vehicle computers. Actual or potential applications of this research include design of in-vehicle information systems and evaluation of their contributions to driver distraction.     

电子文档挖掘技术在电子邮件监控系统中的应用

1 引言随着Internet技术的发展,各种网络应用服务越来越多。其中,网络中广泛应用的电子邮件(E-mail)正成为一种快捷而廉价的通信手段。然而,电子邮件在给人们带来很多方便的同时,也产生了一系列的新问题:有人利用电子邮件出卖机密情报、散布色情淫秽内容,更有人利用电子邮件散发反动传单、蛊惑人心、散布不利于国家稳定、安全的言论,同时各种垃圾邮件、邮件炸弹、虚假广告也给用户收发E-mail带来了极大的困扰。     

CiscoACE在邮件系统中的负载均衡应用

通过分析CiSCOACE模块的负载均衡特点,结合邮件系统的实际情况,分析了负载均衡的具体实施技术,着重介绍了如何解决邮件用户的状态保持问题,最终实现构建了一个高可靠、高可用、高安全的邮件系统,提高了企业的生产效率,改善了用户的使用体验,可供企业建设数据中心参考。     

基于Java电子邮件系统的设计与实现

在介绍电子邮件系统SMTP和POP3协议,JavaMail API结构框架和核心类的基础上,笔者主要阐述的是如何利用JavaMailAPI结合Jsp编程实现电子邮件的收发系统,以实现用户的无障碍交流,系统的主要功能包括用户注册和登陆、接收和发送邮件及附件等管理。     

Rama: An architecture for Internet information filtering

This paper describes Rama, a first generation experimental information retrieval and filtering system that attempts to recover useful information from various Internet sources including USENIX news and anonymous FTP servers. The focus of the Rama system to date has been on building a distributed query and information retrieval system, which provides an interface to heterogeneous information services. A user of Rama sends one or more asynchronous queries to a Rama server using existing SMTP e-mail clients. The server periodically searches local and remote Internet services. Searches are prefiltered with the use of timestamps. Data objects which are newer than the timestamp are then searched via a query mechanism which relies on a combination of vector-distance, pattern matching operands, and boolean operators. Results are weighted according to how closely they match queries and are posted via e-mail to the user. Input to the e-mail client can be further filtered — one can use the MH mail system and sort input by weight. Results indicate that the current system is useful and extensible. So far we have assumed that existing e-mail systems will be used for input and output and have not attempted to construct special client interfaces. Efforts are underway to extend the system with WWW searching capabilities and construct a special WWW oriented user-interface.