构想图：
所需主要源码包：
postfix-2.8.2.tar.gz
courier-authlib-0.63.0.tar.bz2
extmail-1.2.tar.gz，
extman-1.1.tar.gz
Unix-Syslog-0.100.tar.gz
一、安装前的准备工作：
1、安装dns服务 yum install bind bind-chroot caching-nameserver
域名为liuyuan.com 192.168.1.160
主机名为mail.liuyuan.com
2、安装所需的rpm包，这包括以下这些：
httpd, php, php-mysql, mysql, mysql-server, mysql-devel, openssl-devel, dovecot, perl-DBD-MySQL, tcl, tcl-devel, libart_lgpl, libart_lgpl-devel, libtool-ltdl, libtool-ltdl-devel, expect
yum install httpd php php-mysql mysql mysql-server mysql-devel openssl-devel dovecot perl-DBD-MySQL tcl tcl-devel libart_lgpl libart_lgpl-devel libtool-ltdl libtool-ltdl-devel expect
3、关闭sendmail，并将它的随系统自动启动功能关闭：
# service sendmail stop
# chkconfig sendmail off
4、安装以下开发所用到的rpm包组：通过yum grouplist 查看
Development Libraries
Development Tools
Legacy Software Development
X Software Development
注：对应成中文就是:Development Libraries 开发库; Development Tools 开发工具;
Legacy Software Development 老的软件开发; X Software Development X软件开发;
方法：
# yum groupinstall "packge_group_name"
5、启动mysql数据库，并给mysql的root用户设置密码：
# service mysqld start
# chkconfig mysqld on
---------------------------------授权本地用户
mysql> SET PASSWORD FOR root@'localhost'=PASSWORD('redhat');
mysql> SET PASSWORD FOR root@'127.0.0.1'=PASSWORD('redhat');
mysql> FLUSH PRIVILEGES;
-------------------------------授权远程用户
mysql> GRANT ALL PRIVILEGES ON *.* TO root@'%' IDENTIFIED BY 'redhat';
mysql> FLUSH PRIVILEGES;
二、安装配置postfix
1、创建相关用户及组并指定自定义用户id及组id
# groupadd -g 2525 postfix
# useradd -g postfix -u 2525 -s /sbin/nologin -M postfix
# groupadd -g 2526 postdrop
# useradd -g postdrop -u 2526 -s /bin/false -M postdrop
# tar zxvf postfix-2.6.5.tar.gz
# cd postfix-2.6.5
# make makefiles 'CCARGS=-DHAS_MYSQL -I/usr/include/mysql -DUSE_SASL_AUTH -DUSE_CYRUS_SASL -I/usr/include/sasl -DUSE_TLS ' 'AUXLIBS=-L/usr/lib/mysql -lmysqlclient -lz -lm -L/usr/lib/sasl2 -lsasl2 -lssl -lcrypto'
# make
# make install
按照以下的提示输入相关的路径([]号中的是缺省值，”[]”后的是输入值，省略的表示采用默认值)
install_root: [/] /
tempdir: [/usr/local/src/ postfix-2.6.5] /tmp
config_directory: [/etc/postfix] /etc/postfix
daemon_directory: [/usr/libexec/postfix]
command_directory: [/usr/sbin]
data_directory: [/var/lib/postfix]
queue_directory: [/var/spool/postfix]
sendmail_path: [/usr/sbin/sendmail]
newaliases_path: [/usr/bin/newaliases]
mailq_path: [/usr/bin/mailq]
mail_owner: [postfix]
setgid_group: [postdrop]
html_directory: [no] /var/www/html/help #帮助文档
manpages: [/usr/local/man]
readme_directory: [no]
生成别名二进制文件，这个步骤如果忽略，会造成postfix效率极低：
# newaliases
2．进行一些基本配置，测试启动postfix并进行发信
#vi /etc/postfix/main.cf
修改以下几项为您需要的配置
myhostname = mail.liuyuan.com
myorigin = liuyuan.com
mydomain = liuyuan.com
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mynetworks = 192.168.1.0/24, 127.0.0.0/8
说明:
myorigin参数用来指明发件人所在的域名；
mydestination参数指定postfix接收邮件时收件人的域名，即您的postfix系统要接收到哪个域名的邮件；
myhostname 参数指定运行postfix邮件系统的主机的主机名，默认情况下，其值被设定为本地机器名；
mydomain参数指定您的域名，默认情况下，postfix将myhostname的第一部分删除而作为mydomain的值；
mynetworks 参数指定你所在的网络的网络地址，postfix系统根据其值来区别用户是远程的还是本地的，如果是本地网络用户则允许其访问；
inet_interfaces 参数指定postfix系统监听的网络接口；
注意：
1、在postfix的配置文件中，参数行和注释行是不能处在同一行中的；
2、任何一个参数的值都不需要加引号，否则，引号将会被当作参数值的一部分来使用；
3、每修改参数及其值后执行 postfix reload 即可令其生效；但若修改了inet_interfaces，则需重新启动postfix；
4、如果一个参数的值有多个，可以将它们放在不同的行中，只需要在其后的每个行前多置一个空格即可；postfix会把第一个字符为空格或tab的文本行视为上一行的延续；
[root@localhost abc]# rpm2cpio postfix-2.3.3-2.1.el5_2.i386.rpm |cpio -id
16333 blocks
[root@localhost etc]#cp etc/init.d/rc.d/postfix /etc/init.d/
[root@localhost etc]# ll /etc/init.d/postfix
-rwxr-xr-x 1 root root 2404 12-14 17:51 /etc/init.d/postfix
[root@localhost etc]# chkconfig --add postfix
[root@localhost etc]# chkconfig postfix on
启动postfix
#service postfix start
连接postfix，验正服务启动状况：
# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
220 mail.liuyuan.com ESMTP Postfix
ehlo mail.liuyuan.com
250-mail.liuyuan.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
mail from:root@liuyuan.com
250 2.1.0 Ok
rcpt to:user1@liuyuan.com
250 2.1.5 Ok
data
354 End data with <CR><LF>.<CR><LF>
subject:test!
test!!!
.
250 2.0.0 Ok: queued as AB94A1A561
quit
221 2.0.0 Bye
Connection closed by foreign host.
切换到user1用户进行收信：
# su - user1
$ mail
Mail version 8.1 6/6/93. Type ? for help.
"/var/spool/mail/user1": 1 message 1 new
>N 1 root@liuyuan.com Wed Sep 5 10:59 15/488 "test!"
&
三、为postfix开启基于cyrus-sasl的认证功能
使用以下命令验正postfix是否支持cyrus的sasl认证，如果您的输出为以下结果，则是支持的：
# /usr/sbin/postconf -a
cyrus
dovecot
#vi /etc/postfix/main.cf
添加以下内容：
############################CYRUS-SASL############################
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject_invalid_hostname,reject_non_fqdn_hostname,reject_unknown_sender_domain,reject_non_fqdn_sender,reject_non_fqdn_recipient,reject_unknown_recipient_domain,reject_unauth_pipelining,reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_security_options = noanonymous
smtpd_banner = Welcome to our $myhostname ESMTP,Warning: Version not Available!
#vi /usr/lib/sasl2/smtpd.conf
添加如下内容：
pwcheck_method: saslauthd
mech_list: PLAIN LOGIN
启动saslauthd服务，并将其加入到自动启动队列：
# service saslauthd start
# chkconfig saslauthd on
重启postfix服务
#service postfix restart
# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
220 Welcome to our mail.liuyuan.com ESMTP,Warning: Version not Available!
ehlo mail.test.com
250-mail.test.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN （说明已经支持验证）
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
四、安装Courier authentication library
# tar jxvf courier-authlib-0.63.0.tar.bz2 -C /usr/local/src/
# cd /usr/local/src/courier-authlib-0.63.0
#./configure --prefix=/usr/local/courier-authlib --sysconfdir=/etc --with-authmysql --with-mysql-libs=/usr/lib/mysql --with-mysql-includes=/usr/include/mysql --with-redhat --with-authmysqlrc=/etc/authmysqlrc --with-authdaemonrc=/etc/authdaemonrc --with-ltdl-lib=/usr/lib --with-ltdl-include=/usr/include
# make
# make install
# chmod 755 /usr/local/courier-authlib/var/spool/authdaemon
# cp /etc/authdaemonrc.dist /etc/authdaemonrc
# cp /etc/authmysqlrc.dist /etc/authmysqlrc
修改/etc/authdaemonrc 文件
authmodulelist="authmysql"
authmodulelistorig="authmysql"
daemons=10
编辑/etc/authmysqlrc 为以下内容，其中2525，2525 为postfix 用户的UID和GID。
MYSQL_SERVER localhost
MYSQL_PORT 3306 (指定你的mysql监听的端口，这里使用默认的3306)
MYSQL_USERNAME extmail (这是为后文要用的数据库的所有者的用户名)
MYSQL_PASSWORD extmail (extmail用户的密码)
MYSQL_SOCKET /var/lib/mysql/mysql.sock
MYSQL_DATABASE extmail
MYSQL_USER_TABLE mailbox
MYSQL_CRYPT_PWFIELD password
MYSQL_UID_FIELD 2525
MYSQL_GID_FIELD 2525
MYSQL_LOGIN_FIELD username
MYSQL_HOME_FIELD concat('/var/mailbox/',homedir)
MYSQL_NAME_FIELD name
MYSQL_MAILDIR_FIELD concat('/var/mailbox/',maildir)
#cd /usr/local/src/courier-authlib-0.63.0
# cp courier-authlib.sysvinit /etc/init.d/courier-authlib
# chmod 755 /etc/init.d/courier-authlib
# chkconfig --add courier-authlib
# chkconfig --level 2345 courier-authlib on
加载courier-authlib的库文件，
#echo "/usr/local/courier-authlib/lib/courier-authlib" >> /etc/ld.so.conf.d/courier-authlib.conf
# ldconfig -v |more (查看是否正常加载相关库文件)
# service courier-authlib start (启动服务)
Starting Courier authentication services: authdaemond
新建虚拟用户邮箱所在的目录，并将其权限赋予postfix用户：
#mkdir -pv /var/mailbox
#chown -R postfix /var/mailbox
接下来重新配置SMTP 认证，编辑 /usr/lib/sasl2/smtpd.conf ，确保其为以下内容：
pwcheck_method: authdaemond
log_level: 3
mech_list:PLAIN LOGIN
authdaemond_path:/usr/local/courier-authlib/var/spool/authdaemon/socket
#service saslauthd restart (重启saslauthd服务)
五、让postfix支持虚拟域和虚拟用户
1、编辑/etc/postfix/main.cf，添加如下内容：
########################Virtual Mailbox Settings########################
virtual_mailbox_base = /var/mailbox
virtual_mailbox_maps = mysql:/etc/postfix/mysql_virtual_mailbox_maps.cf
virtual_mailbox_domains = mysql:/etc/postfix/mysql_virtual_domains_maps.cf
virtual_alias_domains =
virtual_alias_maps = mysql:/etc/postfix/mysql_virtual_alias_maps.cf
virtual_uid_maps = static:2525
virtual_gid_maps = static:2525
virtual_transport = virtual
maildrop_destination_recipient_limit = 1
maildrop_destination_concurrency_limit = 1
##########################QUOTA Settings########################
message_size_limit = 14336000
virtual_mailbox_limit = 20971520
virtual_create_maildirsize = yes
virtual_mailbox_extended = yes
virtual_mailbox_limit_maps = mysql:/etc/postfix/mysql_virtual_mailbox_limit_maps.cf
virtual_mailbox_limit_override = yes
virtual_maildir_limit_message = Sorry, the user's maildir has overdrawn his diskspace quota, please Tidy your mailbox and try again later.
virtual_overquota_bounce = yes
2、使用extman源码目录下docs目录中的extmail.sql和init.sql建立数据库：
# tar zxvf extman-1.1.tar.gz
# cd extman-1.1/docs
#cp mysql_virtual_* /etc/postfix/
----------将extmail.sql与init.sql导入到mysql数据库中---------------------------------------
# mysql -u root -p <extmail.sql
# mysql -u root -p <init.sql
#mysql -u root -p （进行验证，查看是否导入成功)
3、授予用户extmail访问extmail数据库的权限
mysql> GRANT all privileges on extmail.* TO extmail@localhost IDENTIFIED BY 'extmail';
mysql> GRANT all privileges on extmail.* TO extmail@127.0.0.1 IDENTIFIED BY 'extmail';
mysql>FLUSH PRIVILEGES; 让设置的内容生效
service postfix restart (重启postfix服务)
注意：启用虚拟域以后，需要取消中心域，即注释掉myhostname, mydestination, mydomain, myorigin几个指令；
否则就会报错：
postfix/trivial-rewrite[12839]: warning: do not list domain liuyuan.com in BOTH mydestination and virtual_mailbox_domains
