【作者】 刘建；

【导师】 蒋洪； 韩俊刚；

【作者基本信息】 西安电子科技大学 ， 计算机应用技术， 2002， 硕士

【摘要】 电子邮件作为Internet最基本、最流行的服务之一，随着网民与日俱增，传统的邮件系统已经不能满足人们的需求，为此研究了大容量分布式邮件系统。本文首先介绍了邮件系统的基本原理、标准及模型，并探讨了邮件系统的分布式结构，用户认证、负载均衡及邮件存储。作者应用目录服务(LDAP)对邮件用户进行认证、管理，提高了系统效率和安全性。应用Linux虚拟服务器实现了基于第四层交换的邮件系统的负载均衡，在此基础上，提出并实现了最大稳定剩余连接优先的请求分配算法，并且进行了性能分析。 本文提出了Web Mail、应用网关——应用服务器——邮件服务器三层体系结构，以方便的支持UMS服务。基于公共的免费代码以及上述研究工作，作者设计并实现了分布式邮件系统(实验系统)，在本文中称为信捷邮件系统。信捷邮件系统采用了三层体系结构，具有很好的功能扩展性。为了给用户提供更智能化的信息服务，同时为ISP们愈演愈烈的收费邮件提供更好的解决方案。该邮件系统除了提供基本的邮件服务外，还对电话用户、手机用户、传真用户等提供统一消息服务和邮件到达的实时通知服务。更多还原

【Abstract】 E-mail has been one of the most basic and popular Internet services. With the popularity of Internet and increment of its users, the traditional mail server cannot meet for the need. To solve this problem, the author studied and developed a large-scale distributed email system. This paper first introduces the basic principal, standards protocols, and model of the email system, and probes into its distributed architecture, user authentication, load balance and storage technology. This paper applies LDAP to email user authentication and management, which improve the efficiency and security of the email system. With Linux Virtual Server, this paper implements load balance based on layer-4 switch, and puts forward a new request dispatching algorithm and its implementation.This paper also presents 3-layer architecture for email system: WebMail & application gate- application server- email servers, which is easy to extend applications, such as UMS services. Based on the GUN code and research above, a trial distributed email system named XinJie is, developed. To provide more intelligent information service, and better solution for competitive charging email, XinJie realizes UMS and in-time notice of coming email to users of telephone, SMS and fax.更多还原