一、简介
基于虚拟账号的邮件系统采用的技术如下图所示：
Postfix是Wietse Venema在IBM的GPL协议之下开发的MTA（邮件传输代理）软
件。Postfix是Wietse Venema想要为使用最广泛的sendmail提供替代品的一个尝
试。在Internet世界中，大部分的电子邮件都是通过sendmail来投递的，大约有100
万用户使用sendmail，每天投递上亿封邮件。这真是一个让人吃惊的数字。Postfix试
图更快、更容易管理、更安全，同时还与sendmail保持足够的兼容性。
Postfix 是一种电子邮件服务器，它是由任职于IBM华生研究中心（T.J. Watson
Research Center）的荷兰籍研究员Wietse Venema为了改良sendmail邮件服务器
而产生的。最早在1990年代晚期出现，是一个开放源代码的软件。
Postfix特点
1. postfix是免费的；
2. 更快；
3. 兼容性好；
4. 更健壮；
5. 更灵活；
6. 安全性。
二、案例
首先搭建虚拟机环境：
地址设为：192.168.145.100
[root@localhost ~]# vim /etc/resolv.conf
编辑结果：
nameserver 192.168.145.100
[root@localhost ~]# vim /etc/sysconfig/network
编辑结果：
HOSTNAME=mail.a.org
[root@localhost ~]# vim /etc/hosts
编辑结果：
127.0.0.1 localhost.localdomain localhost
重启虚拟机，环境搭建完成。
挂载光盘：
[root@mail ~]# mkdir /mnt/cdrom
[root@mail ~]# mount /dev/cdrom /mnt/cdrom
[root@mail ~]# cd /mnt/cdrom/Server
编辑yum服务器：
[root@mail Server]# vim /etc/yum.repos.d/rhel-debuginfo.repo
编辑结果：
[rhel-server]
name=Red Hat Enterprise Linux serverbaseurl=file:///mnt/cdrom/Server
enabled=1
gpgcheck=1
gpgkey=file:///mnt/cdrom/RPM-GPG-KEY-redhat-release
搭建DNS服务器：
[root@mail Server]# yum install bind
[root@mail Server]# yum install bind-chroot
[root@mail Server]# yum install caching-nameserver
[root@mail Server]# cd /var/named/chroot/etc
[root@mail etc]# cp -p named.caching-nameserver.conf named.conf
[root@mail etc]# vim named.conf
编辑结果：
options {
listen-on port 53 { any; };
listen-on-v6 port 53 { ::1; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
// Those options should be used carefully because they disable port
// randomization
// query-source port 53;
// query-source-v6 port 53;
allow-query { any; };
allow-query-cache { any; };
};
view localhost_resolver {
match-clients { any; };
match-destinations { any; };
recursion yes;
include "/etc/named.rfc1912.zones";
};
区域声明：
[root@mail etc]# vim named.rfc1912.zones
编辑结果：
27 zone "a.org" IN {
28 type master;
29 file "a.org.zone";
30 allow-update { none; };
31 };
[root@mail etc]# cd ../var/named
[root@mail named]# cp -p localhost.zone a.org.zone
[root@mail named]# vim a.org.zone
编辑结果：
1 $TTL 86400
2 @ IN SOA ns.a.org. root (
3 42 ; serial (d. ada ms)
4 3H ; refresh
5 15M ; retry
6 1W ; expiry
7 1D ) ; minimum
8
9 IN NS ns.a.org.
10 ns IN A 192.168.145.100
11 mail IN A 192.168.145.100
12 pop3 IN CNAME mail
13 smtp IN CNAME mail
14 @ IN MX 10 mail
[root@mail named]# service named start
启动 named： [确定]
[root@mail named]# rndc reload
server reload successful
[root@mail named]# chkconfig named on
DNS服务器搭建完成。
关闭sendmail：
[root@mail named]# service sendmail stop
关闭 sm-client： [确定]
关闭 sendmail： [确定]
[root@mail named]# chkconfig sendmail off
安装相关软件：
[root@mail named]# 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
启动mysql：
[root@mail named]# service mysqld start
[root@mail named]# chkconfig mysqld on
为mysql用户设置权限：
[root@mail named]# mysql
本地用户：
mysql> SET PASSWORD FOR root@'localhost'=PASSWORD('redhat');
Query OK, 0 rows affected (0.00 sec)
mysql> SET PASSWORD FOR root@'127.0.0.1'=PASSWORD('redhat');
Query OK, 0 rows affected (0.00 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
远程用户：
mysql> GRANT ALL PRIVILEGES ON *.* TO root@'%' IDENTIFIED BY 'redhat';
Query OK, 0 rows affected (0.00 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
mysql> \quit
Bye
安装配置postfix：
[root@mail ~]# tar -zxvf postfix-2.8.2.tar.gz -C /usr/local/src
[root@mail ~]# cd /usr/local/src
[root@mail src]# ls
postfix-2.8.2
[root@mail src]# cd postfix-2.8.2/
添加组和账号：
[root@mail postfix-2.8.2]# groupadd -g 2525 postfix
[root@mail postfix-2.8.2]# useradd -g postfix -u 2525 -s /sbin/nologin –M
postfix
[root@mail postfix-2.8.2]# groupadd -g 2526 postdrop
[root@mail postfix-2.8.2]# useradd -g postdrop -u 2526 -s /bin/false –M
postdrop
生成makefile文件：
[root@mail postfix-2.8.2]# 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'
编译：
[root@mail postfix-2.8.2]# make
安装：
[root@mail postfix-2.8.2]# make install
install_root: [/]
tempdir: [/usr/local/src/postfix-2.8.2] /tmp
config_directory: [/etc/postfix]
command_directory: [/usr/sbin]
daemon_directory: [/usr/libexec/postfix]
data_directory: [/var/lib/postfix]
html_directory: [no]
mail_owner: [postfix]
mailq_path: [/usr/bin/mailq]
manpage_directory: [/usr/local/man]
newaliases_path: [/usr/bin/newaliases]
queue_directory: [/var/spool/postfix]
readme_directory: [no]
sendmail_path: [/usr/sbin/sendmail]
setgid_group: [postdrop]
生成别名二进制文件：
[root@mail postfix-2.8.2]# newaliases
[root@mail postfix-2.8.2]# postfix start
[root@mail postfix-2.8.2]# vim /etc/postfix/main.cf
编辑结果：
75 myhostname = mail.a.org
83 mydomain = a.org
99 myorigin = $mydomain
113 inet_interfaces = all
161 mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
260 mynetworks = 127.0.0.0/8
[root@mail postfix-2.8.2]# postfix stop
postfix/postfix-script: stopping the Postfix mail system
[root@mail postfix-2.8.2]# postfix start
postfix/postfix-script: starting the Postfix mail system
为postfix开启基于cyrus-sasl的认证功能：
[root@mail postfix-2.8.2]# vim /etc/postfix/main.cf
编辑结果：
653 ############################CYRUS-SASL############################
654 broken_sasl_auth_clients = yes
655 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_r ecipient_domain,reject_unauth_pipelining,reject_unauth_destination
656 smtpd_sasl_auth_enable = yes
657 smtpd_sasl_local_domain = $myhostname
658 smtpd_sasl_security_options = noanonymous
659 smtpd_banner = Welcome to our $myhostname ESMTP,Warning: Version not Ava ilable!
[root@mail postfix-2.8.2]# cd /usr/lib/sasl2
[root@mail sasl2]# cp -p Sendmail.conf smtpd.conf
[root@mail sasl2]# vim smtpd.conf
编辑结果：
pwcheck_method:saslauthd
mech_list:LOGIN PLAIN
[root@mail sasl2]# service saslauthd start
启动 saslauthd： [确定]
[root@mail sasl2]# chkconfig saslauthd on
安装Courier authentication library：
[root@mail ~]# tar -jxvf courier-authlib-0.63.1.20111230.tar.bz2 -C /usr/local/src
[root@mail ~]# cd /usr/local/src
[root@mail src]# ls
courier-authlib-0.63.1.20111230 postfix-2.8.2
[root@mail src]# cd courier-authlib-0.63.1.20111230/
[root@mail courier-authlib-0.63.1.20111230]# ./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
[root@mail courier-authlib-0.63.1.20111230]# make
[root@mail courier-authlib-0.63.1.20111230]# make install
[root@mail courier-authlib-0.63.1.20111230]# chmod 755 /usr/local/courier-authlib/var/spool/authdaemon
[root@mail courier-authlib-0.63.1.20111230]# cp /etc/authdaemonrc.dist /etc/authdaemonrc
[root@mail courier-authlib-0.63.1.20111230]# cp /etc/authmysqlrc.dist /etc/authmysqlrc
[root@mail courier-authlib-0.63.1.20111230]# vim /etc/authdaemonrc
编辑结果：
authmodulelist="authmysql"
authmodulelistorig="authmysql"
daemons=10
[root@mail courier-authlib-0.63.1.20111230]# vim /etc/authmysqlrc
编辑结果：
MYSQL_SERVER localhost
MYSQL_USERNAME extmail
MYSQL_PASSWORD extmail
MYSQL_PORT 3306
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)
[root@mail courier-authlib-0.63.1.20111230]# cp courier-authlib.sysvinit /etc/init.d/courier-authlib
[root@mail courier-authlib-0.63.1.20111230]# chmod 755 /etc/init.d/courier-authlib
[root@mail courier-authlib-0.63.1.20111230]# chkconfig --add courier-authlib
[root@mail courier-authlib-0.63.1.20111230]# chkconfig --level 2345 courier-authlib on
[root@mail courier-authlib-0.63.1.20111230]# echo "/usr/local/courier-authlib/lib/courier-authlib" >> /etc/ld.so.conf.d/courier-authlib.conf
[root@mail courier-authlib-0.63.1.20111230]# ldconfig –v
[root@mail courier-authlib-0.63.1.20111230]# service courier-authlib start
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：
[root@mail courier-authlib-0.63.1.20111230]# mkdir -pv /var/mailbox
[root@mail courier-authlib-0.63.1.20111230]# chown -R postfix /var/mailbox
重新配置SMTP 认证：
[root@mail courier-authlib-0.63.1.20111230]# cd /usr/lib/sasl2
[root@mail sasl2]# vim smtpd.conf
编辑结果：
pwcheck_method:authdaemond
mech_list:LOGIN PLAIN
authdaemond_path:/usr/local/courier-authlib/var/spool/authdaemon/socket
让postfix支持虚拟域和虚拟用户
[root@mail ~]# vim /etc/postfix/main.cf
编辑结果：
661 ########################Virtual Mailbox Settings########################
662 virtual_mailbox_base = /var/mailbox
663 virtual_mailbox_maps = mysql:/etc/postfix/mysql_virtual_mailbox_maps.cf
664 virtual_mailbox_domains = mysql:/etc/postfix/mysql_virtual_domains_maps. cf
665 virtual_alias_domains =
666 virtual_alias_maps = mysql:/etc/postfix/mysql_virtual_alias_maps.cf
667 virtual_uid_maps = static:2525
668 virtual_gid_maps = static:2525
669 virtual_transport = virtual
670 maildrop_destination_recipient_limit = 1
671 maildrop_destination_concurrency_limit = 1
672 ##########################QUOTA Settings########################
673 message_size_limit = 14336000
674 virtual_mailbox_limit = 20971520
675 virtual_create_maildirsize = yes
676 virtual_mailbox_extended = yes
677 virtual_mailbox_limit_maps = mysql:/etc/postfix/mysql_virtual_mailbox_li mit_maps.cf
678 virtual_mailbox_limit_override = yes
679 virtual_maildir_limit_message = Sorry, the user's maildir has overdrawn his diskspace quota, please Tidy your mailbox and try again later.
680 virtual_overquota_bounce = yes
使用extman源码目录下docs目录中的extmail.sql和init.sql建立数据库：
[root@mail ~]# tar -zxvf extman-1.1.tar.gz -C /usr/local/src
[root@mail ~]# cd /usr/local/src
[root@mail src]# ls
courier-authlib-0.63.1.20111230 extman-1.1 postfix-2.8.2
[root@mail src]# cd extman-1.1/docs
[root@mail docs]# mysql -u root -p
[root@mail docs]# mysql -u root -p <init.sql
Enter password:
[root@mail docs]# cp mysql* /etc/postfix/
授予用户extmail访问extmail数据库的权限：
[root@mail docs]# mysql -u root -p
Enter password:
mysql> GRANT all privileges on extmail.* TO extmail@localhost IDENTIFIED BY 'extmail';
Query OK, 0 rows affected (0.01 sec)
mysql> GRANT all privileges on extmail.* TO [email protected] IDENTIFIED BY 'extmail';
Query OK, 0 rows affected (0.00 sec)
mysql> FLUSH PRIVILEGES;
Query OK, 0 rows affected (0.00 sec)
mysql> \quit
Bye
[root@mail docs]# cp mysql_virtual_* /etc/postfix/
[root@mail docs]# postfix stop
postfix/postfix-script: stopping the Postfix mail system
[root@mail docs]# postfix start
postfix/postfix-script: starting the Postfix mail system
说明：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；当然，你也可以把mydestionation的值改为你自己需要的。
配置dovecot
[root@mail ~]# vim /etc/dovecot.conf
编辑结果:
mail_location = maildir:/var/mailbox/%d/%n/Maildir
auth default {
mechanisms = plain
passdb sql {
args = /etc/dovecot-mysql.conf
}
userdb sql {
args = /etc/dovecot-mysql.conf
}
[root@mail ~]# vim /etc/postfix/main.cf
编辑结果：
415 home_mailbox = Maildir/
[root@mail ~]# vim /etc/dovecot-mysql.conf
编辑结果：
driver = mysql
connect = host=localhost dbname=extmail user=extmail password=extmail
default_pass_scheme = CRYPT
password_query = SELECT username AS user,password AS password FROM mailbox WHERE username = '%u'
user_query = SELECT maildir, uidnumber AS uid, gidnumber AS gid FROM mailbox WHERE username = '%u'
[root@mail ~]# service dovecot start
启动 Dovecot Imap： [确定]
[root@mail ~]# chkconfig dovecot on
安装Extmail-1.2（先安装httpd）
[root@mail ~]# tar -zxvf extmail-1.2.tar.gz -C /usr/local/src
[root@mail ~]# cd /usr/local/src
[root@mail src]# ls
courier-authlib-0.63.1.20111230 extmail-1.2 extman-1.1 postfix-2.8.2
[root@mail src]# cd extmail-1.2/
[root@mail extmail-1.2]# mkdir -pv /var/www/extsuite
[root@mail src]# mv extmail-1.2 /var/www/extsuite/extmail
[root@mail src]# cp /var/www/extsuite/extmail/webmail.cf.default
/var/www/extsuite/extmail/webmail.cf
[root@mail src]# vim /var/www/extsuite/extmail/webmail.cf
编辑结果：
127 SYS_MAILDIR_BASE = /var/mailbox
139 SYS_MYSQL_USER = extmail
140 SYS_MYSQL_PASS = extmail
197 SYS_AUTHLIB_SOCKET = /usr/local/courier-authlib/var/spool/authdaemon/socket
[root@mail src]# vim /etc/httpd/conf/httpd.conf
编辑结果：
231 User postfix
232 Group postfix
993
994 ServerName mail.a.org
995 DocumentRoot /var/www/extsuite/extmail/html/
996 ScriptAlias /extmail/cgi /var/www/extsuite/extmail/cgi
997 Alias /extmail /var/www/extsuite/extmail/html
998 SuexecUserGroup postfix postfix
999
依赖关系的解决：
[root@mail ~]# tar -zxvf Unix-Syslog-1.1.tar.gz -C /usr/local/src
[root@mail ~]# cd /usr/local/src
[root@mail src]# ls
courier-authlib-0.63.1.20111230 extman-1.1 postfix-2.8.2 Unix-Syslog-1.1
[root@mail src]# cd Unix-Syslog-1.1/
[root@mail Unix-Syslog-1.1]# perl Makefile.PL
[root@mail Unix-Syslog-1.1]# make
[root@mail Unix-Syslog-1.1]# service httpd start
启动 httpd：httpd: Could not reliably determine the server's fully qualified domain name, using mail.a.org for ServerName [确定]
[root@mail Unix-Syslog-1.1]# chkconfig httpd on
安装Extman-1.1
[root@mail ~]# tar -zxvf extman-1.1.tar.gz -C /usr/local/src
[root@mail ~]# cd /usr/local/src
[root@mail src]# mv extman-1.1 /var/www/extsuite/extman
[root@mail src]#cp /var/www/extsuite/extman/webman.cf.default
/var/www/extsuite/extman/webman.cf
[root@mail src]# vi /var/www/extsuite/extman/webman.cf
编辑结果：
12 SYS_MAILDIR_BASE = /var/mailbox
21 SYS_CAPTCHA_ON = 0
[root@mail src]# chown -R postfix.postfix /var/www/extsuite/extman/cgi/
[root@mail src]# vim /etc/httpd/conf/httpd.conf
编辑结果：
ServerName mail.a.org
DocumentRoot /var/www/extsuite/extmail/html/
ScriptAlias /extmail/cgi /var/www/extsuite/extmail/cgi
Alias /extmail /var/www/extsuite/extmail/html
ScriptAlias /extman/cgi /var/www/extsuite/extman/cgi
Alias /extman /var/www/extsuite/extman/html
SuexecUserGroup postfix postfix
[root@mail src]# mkdir -pv /tmp/extman
[root@mail src]# chown postfix.postfix /tmp/extman
[root@mail src]# service httpd restart
停止 httpd： [确定]
启动 httpd：httpd: Could not reliably determine the server's fully qualified domain name, using mail.a.org for ServerName [确定]
安装完成。