代写论文：电子邮件系统
随着电子邮件的日益普及，电子邮件系统的安全性被证明是整个网络安全网络的重要组成部分。一个不安全的邮件服务器很容易受到攻击，比如垃圾邮件、对邮件的入侵和拒绝服务。针对这些事实，本文对主要邮件服务器的功能和操作进行了比较和分析。详细描述了各自的优缺点，并讨论了Postfix的特性和相关配置问题，这是最流行、最具成本效益的邮件服务器之一。一般来说，由于高效的电子邮件系统和高安全性的性能，Postfix的受欢迎程度有所上升。然而，尽管它有反垃圾邮件功能，但它仍然需要专业的软件支持来处理当前在线社区越来越多的spams。
代写论文：电子邮件系统
With the increasing spread of e-mails, the security of e-mail system proves to be a paramount part of the whole online security network. An insecure mail server is vulnerable to attacks, such as junk mails, intrusion to the mail relay and the denial of service. In light of these facts, this essay introduces compares and analyzes the functions and operations of major mail servers. With detailed description of respective advantages and disadvantages, it also discusses the characteristics and related configuration issues of Postfix, one of the most popular and cost-effective mail servers. In general, Postfix has experienced escalating popularity, due to its efficient e-mail system and high security performance. However, although it has anti-spam functions, it still needs professional software support to deal with the increasing number of spams in the current online community.
