UbuntuHelp:PostfixCompleteVirtualMailSystemHowto/zh

It is important to know how our system works before going to install. A virtual mail system needs to be able to handle email for numerous domains with multiple users over a variety of interfaces. When you handle multiple domains within the same mail system it presents you some management issues. We have to answer these issues using our technology. Assume ,for example you may have following questions to answer.

开始安装之前，必须了解我们的系统是如何工作的。一个虚拟邮件系统必须能够控制许多域，这些域有很多用户并且用户使用不同接口。当你在同一个邮件系统中控制多个域的时候，虚拟邮件系统会提出一些管理问题。我们必须用我们的技术回答这些问题。例如，你有下面的问题需要回答。

   * What will you do if you have two users which require same username for different domains? 

如果有两个用户在不同的域中使用了同一个用户名，你怎么办？

   * If you are providing imap access and smtp-auth, how do combine the various authentication daemons into a single system? 

如果你提供了IMAP访问和smtp认证，如何将不同的认证值守程序组合在同一个系统中呢？

   * How do you provide security for the numerous components that comprise the system? 

如何保证构成系统的各个组件的安全性？

   * What we can do, if users are asking their own spam filtering policies. 

如果用户要求使用自己的垃圾邮件过滤策略，我们应该如何处理？

   * Individual domain administrators are asking a web-based interface to manage their mail domains 

每一个域的管理员要求使用基于web接口来管理他们的邮件域。

   * How do you setup a web-based management system for Postfix? 

如何为postfix建立一个基于web的管理系统。

   * Each user needs a web-base interface to change his mail account's password 

每个用户要求基于web接口改变邮件帐户密码。

   * How you are going backup user account database and disaster recovery? 

如何备份用户帐号数据库及灾难恢复。

   * Utilizing ssl for transport layer security 

利用ssl实现传输层安全。

   * Handle mailing lists for any domain 

控制任何一个域的邮件列表。

How do you manage all these issues together?Don't panic, I will answer all these questions one by one. Be happy and continue to read this howto.

你如何一起处理以上所有问题？不要担心，我会逐个回答这些问题。高高兴兴地继续读下去。 [编辑] What You Get

使用这个系统你会得到什么？

   * Web based system administration 

基于web的系统管理

   * Unlimited number of domains 

域的数量没有限制

   * Virtual mail users without the need for shell accounts 

与操作系统用户无关的虚拟邮件用户

   * Domain specific user names 

特定域用户名

   * Mailbox quotas 

邮箱容量分配

   * Web access to email accounts 

通过web访问邮件帐号

   * Web base interface to change user passwords 

基于web接口改变用户密码

   * IMAP and POP3 support 

支持IMAP，POP3

   * Auto responders 

自动回复

   * SMTP Authentication for secure relaying 

SMTP认证保证安全中转

   * SSL for transport layer security 

SSL保证传输层安全

   * Strong SPAM filtering 

强力垃圾邮件过滤

   * Anti-Virus filtering 

反病毒过滤

   * Log Analysis 

日志分析 [编辑] Packages Required

The following packages are need to implement our system and most of these packages are in APT repositories. In our installation section you will learn how to install and configure each. 我们系统必须使用下列程序包，大多数可以在APT中找到。在安装小节部分，你会学会如何安装和配置他们。

   * Webmin
   * Postfix
   * MySQL
   * Apache
   * PHP
   * Postfixadmin
   * Courier-IMAP
   * Courier-POP3
   * Courier-authlib
   * Cyrus-SASL
   * Ispell
   * Squirrelmail
   * Awstats
   * Amavisd-new
   * Spamassassin
   * MailZu
   * Razor
   * DCC
   * Pyzor
   * SQLgrey
   * Sgwi
   * Clamav 

[编辑] The Big Picture

整体架构图 The following figure shows the big picture of our setup. If you look at it carefully the figure itself is self explanatory.

下面图示了我们建立的整体架构，如果你仔细观察这张图，你能从图上了解整个系统。

PostfixCompleteVirtualMailSystemHowto?action=AttachFile&do=get&target=CompleteSetupOverview.png

In our setup:

   * Postfix Mail Transfer Agent receives emails via the SMTP protocol and delivers them to different places on your hard disk.
   * MySQL database server stores the information to control the behavior of postfix. It knows about users, domains, email forwarding and passwords.
   * Courier is a standalone mail server just like Postfix but we just use its POP3/IMAP server component to let users access the mailboxes.
   * SASL, the Cyrus library is using to authenticate your users who are dialed in at another ISP while they are on the road they get an IP address outside of your network. Your mail server however only trusts local IP addresses. The SASL ,Simple Authentication and Security Layer, adds authentication to SMTP and makes your mail server trust them. 

在我们的系统中：

   * Postfix：负责通过MTA接收和发送emails。
   * MySQL ：数据库服务器保存postfix的控制信息。主要涉及用户信息，域信息，email转发及密码
   * Courier ：像postfix一样的独立的邮件服务，我们利用它的pop3/IMAP服务部件使用户访问邮箱。
   * SASL：简单认证与安全层 。你的邮件服务仅信任内部地址，所以对使用外部网络地址的用户进行身份认证。通过SASL对SMTP认证使你的邮件服务信任他们。