dovecot+mysql
1.安装服务：
yum install dovecot dovecot-mysql -y
##dovecot-mysql dovecot软件的插件，让软件可以识别mysql
2.更改配置文件：
vim /etc/dovecot/dovecot.conf
24 protocols = imap pop3 lmtp ##支持收件协议
48 login_trusted_networks = 0.0.0.0/0 ##信任网络
49 disable_plaintext_auth = no ##开启明文认证
vim/etc/dovecot/conf.d/10-auth.conf
123 !include auth-sql.conf.ext ##开启mysql的认证方式
#生成dovecot读取mysql的配置
cp/usr/share/doc/dovecot-2.2.10/example-config/dovecot-sql.conf.ext/etc/dovecot/dovecot-sql.conf.ext
vim/etc/dovecot/dovecot-sql.conf.ext
32 driver = mysql ##数据库类型
71 connect = host=localhost dbname=emailuser=postuser password=postuser ##查询时用到库、用户、密码
78 default_pass_scheme = PLAIN ##默认认证方式为明文
107 password_query = \ ##查询密码匹配
108 SELECT username, domain, password \
109 FROM users WHERE username = '%u' AND domain = '%d'
125 user_query = SELECT maildir, 666 AS uid, 666 AS gid FROM emailuserWHERE username = '%u' ##查询邮件内容
vim /etc/dovecot/conf.d/10-mail.conf
30 mail_location = maildir:/home/vmail/%d/%n ##指定邮件位置
168 first_valid_uid = 666 ##邮件文件查询用户身份
175 first_valid_gid = 666
systemctl restart dovecot
空壳邮件
vim /etc/postfix/main.cf
75 myhostname =nullmail.example.com
83 mydomain = example.com
99 myorigin=westos.com
113 inet_interfaces = all
164 mydestination=
316 relayhost=172.25.254.122