電子郵件過濾系統設計與實作

Abstract

隨著網際網路的發達，電子郵件(Electronic mail, E-mail)也逐漸成為網際網路上重量級的應用軟體，越來越多人利用電子郵件做為主要溝通和傳遞訊息的工具。因此，電子郵件除了成為駭客散播病毒的主要管道之外，從 1978 年開始出現垃圾郵件之後，垃圾郵件數量的快速成長，對於電子郵件的使用者也已經造成莫大的困擾。 電子郵件過濾系統是一套架設於電子郵件閘道口的郵件安全系統，整合防毒引擎、垃圾郵件阻擋工具以及多樣化的反垃圾郵件技術，可以偵測並過濾郵件病毒與垃圾郵件。 電子郵件過濾系統提供友善的 web-based 管理介面，方便管理者進行系統管理，並提供完善的郵件紀錄與統計報表，協助管理者追蹤分析病毒郵件與垃圾郵件。

Nowadays, email is growing on communications between corporations, educational institutions, government agencies, and all kinds of organizations. Due to this, the importance of their email systems is enhancing within their information infrastructure. However, the significant growth of spam, viruses and other types of email-borne attacks in the past year is causing the system managers to face more challenges in managing and protecting this critical communications asset. In this thesis, we designed and implemented an intelligent e-mail filter, EMF (Electronic Mail Filtering system), which is a general purpose Internet mail filtering tool. It acts as an email gateway to filter inbound and outbound messages by enforcing an organization’s email policies. It can be used to block junk mail, prohibit mail relaying, and diffuse mail bomb attacks. In the EMF system, we also provided a web-based administrative interface for the system administrators to do the system configuration and to set up their filtering policies. The EMF system can also give detail statistics and reports that will give a great help to the administrators for the analysis task.