【作者】 王博；

【导师】 贺红； 王振友；

【作者基本信息】 山东理工大学 ， 计算机应用， 2006， 硕士

【摘要】 随着电子邮件的广泛应用,各种垃圾、病毒邮件入侵邮件系统,严重影响邮件系统的正常使用。目前更多过滤系统是通过采用设置IP策略、邮件标题查找、MIME长度限制或具有一定智能查找的算法等方案来在单机上实现。本方案主要采用设计垃圾、病毒邮件收集中心,搜集来自不同客户端的配制策略,收集中心对数据进行综合评定,根据处理结果决定是否通知邮件服务器,如果通知邮件服务器,服务器更新数据库,此方案使邮件服务器及时的发现垃圾、病毒邮件,节省了网络带宽并提高了过滤准确效率,也节省了宝贵的系统资源。 在邮件过滤系统设计中,利用了JAVAMAIL软件包的开发技术,涉及基于邮件附件大小、垃圾词语、垃圾邮件产生源地址及病毒过滤等方面,缩短了开发周期。同时,山于JAVAMAIL是JAVA语言的一个子集,自然,在界面开发中用了JAVA开发工具。并且,由于垃圾、病毒邮件是在动态变化的,如何高效准确快速的进行判断是软件设计中要考虑的一个非常重要的因素。对此,本系统设计了采用基于CORBA技术的收集中心,它的主要工作是收集来自不同客户端的邮件数据,对从不同客户端采集来的数据进行分类整理、综合测评,对不同等级的可疑词语、短语、句子或者附件进行评价,将得到的结果在本地数据库保存,并及时通知邮件服务器对数据进行更新。 邮件过滤系统的设计离不开对传统邮件系统的深入研究,本文也详细剖析了邮件系统从高层到底层的实现过程,包括其中涉及到的不同层次的协议、服务与接口等。同时,在实现过程中也用到了一些邮件协议,比如:SMTP协议、POP协议和IMAP协议等。并且,在过滤过程中需要对邮件格式进行处理,这涉及到MIME,如何按照一定的MIME格式对邮件内容进行提取,也是邮件过滤的一个很重要的方面。同时,在对邮件附件过滤过程中,需要进行很多相关的提取处理,在用JAVAMAIL开发过程中,这也是很重要的一个方面。 在对附件处理过程中,需要进行扫描、查毒处理,查毒可以采用多种方式。本设计主要采用按特征值进行查毒的方式,该方法快速,实现简单,但是在对付一些变种病毒邮件上,由于该方法自适应能力差,所以有一定的限制。同时,病毒特征码数据库也要能进行动态的更新,以求能实时的进行邮件扫描。更多还原

【Abstract】 With the wide application of E-mail, all kinds of junk mail or virus have invaded the E-mail system, serious impacting on it’s common using. Currently, more filter systems implement themselves through adopting the setting of IP policy, researching the caption of E-mail, giving the limitation of the MIME format, or running the special algorithm involving in the intellective finding on the single computer. This scheme mainly adopts the way setting up the collecting center of junk or virus mail, collecting the data coming from the different computers, at the same time, gives the synthesis assess. If some new data has updated, the center notices the mail server for updating its database. Naturally, it can make the mail server discover the junk mail or virus mail. Meanwhile, it saves the network bandwidth and system resources and also improves the efficiency of mail filter.During its design, I use JAVAMAIL package for checking the junk words or junk mail address, etc. It can short the time for software tapping. Meanwhile, as JAVAMAIL is one subset of java language, naturally, I use java in designing my interface. Furthermore, because the form of virus or junk mail is changeable dynamically, one important factor is how to judge fast what it belong to. So, this system takes advantage of CORBA technique. Its main work is collecting the data coming from different clients and noticing mail server for updating the database of mail server.The filter system is based on the deep research in the e-mail system. This paper also analyses detailed how the system runs from high layer to low layer, including in the different protocol, service and interface. Meanwhile, it also uses some mail protocol such as SMTP, POP and IMAP. Furthermore, it need handle the mail format, involving in MIME protocol. How to distill some important information from mail is also one considerable side. In this way, JAVAMAIL expresses its value.During handling the mail accessories, one work is scanning virus and killing them if existed. It is implemented on the system by the key value of each virus. This way makes this work easy and simple, but when handling some transformed virus, it is very limited as it has a weak self-fitted capacity. Meanwhile, in order to scan virus in real time way, the virus database need dynamic update.更多还原