CentOS 5.5 x64上使用Postfix + Dovecot + MySQL搭建郵件服務器

最近公司需要一臺郵件服務器，在查閱了大量的資料以後決定採用Postfix + Dovecot + MySQL來搭建這套郵件系統。由於僅僅需要通過客戶端來收發郵件，因此不安裝Postfixadmin這類WEB管理工具。 

系統環境 

操作系統：CentOS 5.5 x64  

安裝需要的包 

更新系統

yum update

YUM安裝Postfix,Dovecot,MySQL

CentOS base和update repository的Postfix版本不包括對MySQL的支持，我們需要從CentOS plus repository安裝Postfix，在使用YUM安裝之前，先修改etc/yum.repos.d/CentOS-Base.repo文件

[base]
name=CentOS-$releasever - Base
...
exclude=postfix*

#released updates
[updates]
name=CentOS-$releasever - Updates
...
exclude=postfix*

YUM安裝所需軟件包

yum --enablerepo=centosplus install postfix
yum install dovecot mysql-server

配置MySQL 

設置MySQL開機啓動

chkconfig mysqld on
service mysqld start

設置root密碼，刪除匿名賬號，刪除test庫

mysql_secure_installation

創建Virtual Domains和Users 

登陸MySQL,創建postfix數據庫

CREATE DATABASE postfix

創建MySQL賬號，並賦權限 

GRANT SELECT, INSERT, UPDATE, DELETE ON postfix.* TO 'postfix_admin'@'localhost' IDENTIFIED BY 'postfix_admin_password';
GRANT SELECT, INSERT, UPDATE, DELETE ON postfix.* TO 'postfix_admin'@'localhost.locahdomain' IDENTIFIED BY 'postfix_admin_password';
FLUSH PRIVILEGES;

創建表結構 

CREATE TABLE domains (domain varchar(50) NOT NULL, PRIMARY KEY (domain) );
CREATE TABLE forwardings (source varchar(80) NOT NULL, destination TEXT NOT NULL, PRIMARY KEY (source) );
CREATE TABLE users (email varchar(80) NOT NULL, password varchar(20) NOT NULL, PRIMARY KEY (email) );
CREATE TABLE transport ( domain varchar(128) NOT NULL default '', transport varchar(128) NOT NULL default '', UNIQUE KEY domain (domain) );

配置Postfix

創建virtual domain配置文件/etc/postfix/mysql-virtual_domains.cf

user = postfix_admin
password = postfix_admin_password
dbname = postfix
query = SELECT domain AS virtual FROM domains WHERE domain='%s'
hosts = 127.0.0.1

創建virtual forwarding配置文件/etc/postfix/mysql-virtual_forwardings.cf

user = postfix_admin
password = postfix_admin_password
dbname = postfix
query = SELECT destination FROM forwardings WHERE source='%s'
hosts = 127.0.0.1

創建virtual mailbox配置文件/etc/postfix/mysql-virtual_mailboxes.cf

user = postfix_admin
password = postfix_admin_password
dbname = postfix
query = SELECT CONCAT(SUBSTRING_INDEX(email,'@',-1),'/',SUBSTRING_INDEX(email,'@',1),'/') FROM users WHERE email='%s'
hosts = 127.0.0.1

創建virtual email配置文件/etc/postfix/mysql-virtual_email2email.cf

user = postfix_admin
password = postfix_admin_password
dbname = postfix
query = SELECT email FROM users WHERE email='%s'
hosts = 127.0.0.1

給配置文件設置合適的權限

chmod o= /etc/postfix/mysql-virtual_*.cf
chgrp postfix /etc/postfix/mysql-virtual_*.cf

創建處理email的用戶和組，所有的郵件都會存放在該用戶的home目錄下

groupadd -g 5000 vmail
useradd -g vmail -u 5000 vmail -d /home/vmail -m

執行以下命令完成Postfix的配置

postconf -e 'myhostname = server.example.com'
postconf -e 'mydestination = $myhostname, localhost, localhost.localdomain'
postconf -e 'mynetworks = 127.0.0.0/8'
postconf -e 'inet_interfaces = all'
postconf -e 'message_size_limit = 30720000'
postconf -e 'virtual_alias_domains ='
postconf -e 'virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf, mysql:/etc/postfix/mysql-virtual_email2email.cf'
postconf -e 'virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains.cf'
postconf -e 'virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailboxes.cf'
postconf -e 'virtual_mailbox_base = /home/vmail'
postconf -e 'virtual_uid_maps = static:5000'
postconf -e 'virtual_gid_maps = static:5000'
postconf -e 'smtpd_sasl_type = dovecot'
postconf -e 'smtpd_sasl_path = private/auth'
postconf -e 'smtpd_sasl_auth_enable = yes'
postconf -e 'broken_sasl_auth_clients = yes'
postconf -e 'smtpd_sasl_authenticated_header = yes'
postconf -e 'smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination'
postconf -e 'smtpd_use_tls = yes'
postconf -e 'smtpd_tls_cert_file = /etc/pki/dovecot/certs/dovecot.pem'
postconf -e 'smtpd_tls_key_file = /etc/pki/dovecot/private/dovecot.pem'
postconf -e 'virtual_create_maildirsize = yes'
postconf -e 'virtual_maildir_extended = yes'
postconf -e 'proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $virtual_mailbox_limit_maps'
postconf -e 'virtual_transport = dovecot'
postconf -e 'dovecot_destination_recipient_limit = 1'

編輯/etc/postfix/master.cf文件，在文件底部增加dovecot服務

dovecot   unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail:vmail argv=/usr/libexec/dovecot/deliver -f ${sender} -d ${recipient}

停止sendmail，啓動postfix

service sendmail stop
chkconfig sendmail off
chkconfig postfix on
service postfix start

Postfix配置到這裏就完成了

配置Dovecot

Dovecot的配置文件是/etc/dovecot.conf，在編輯之前我們先備份一下

cp -a /etc/dovecot.conf /etc/dovecot.conf-backup

修改/etc/dovecot.conf，修改過後的配置文件應該是這樣的

grep -v "#" /etc/dovecot.conf | sed "/^\s*$/d"

protocols = imap imaps pop3 pop3s
log_timestamp = "%Y-%m-%d %H:%M:%S "
mail_location = maildir:/home/vmail/%d/%n/Maildir
ssl_cert_file = /etc/pki/dovecot/certs/dovecot.pem
ssl_key_file = /etc/pki/dovecot/private/dovecot.pem
namespace private {
    separator = .
    prefix = INBOX.
    inbox = yes
}
protocol lda {
    log_path = /home/vmail/dovecot-deliver.log
    auth_socket_path = /var/run/dovecot/auth-master
    postmaster_address = [email protected]
}
protocol pop3 {
    pop3_uidl_format = %08Xu%08Xv
}
auth default {
    user = root
    passdb sql {
        args = /etc/dovecot-sql.conf
    }
    userdb static {
        args = uid=5000 gid=5000 home=/home/vmail/%d/%n allow_all_users=yes
    }
    socket listen {
        master {
            path = /var/run/dovecot/auth-master
            mode = 0600
            user = vmail
        }
        client {
            path = /var/spool/postfix/private/auth
            mode = 0660
            user = postfix
            group = postfix
        }
    }
}

 由於用戶名和密碼是存放在MySQL中的，因此我們需要創建配置文件/etc/dovecot-sql.conf

driver = mysql
connect = host=127.0.0.1 dbname=postfix user=postfix_admin password=postfix_admin_password
default_pass_scheme = CRYPT
password_query = SELECT email as user, password FROM users WHERE email='%u';

更改/etc/dovecot-sql.conf權限，只允許dovecot組訪問

chgrp dovecot /etc/dovecot-sql.conf
chmod o= /etc/dovecot-sql.conf

啓動Dovecot

chkconfig dovecot on
service dovecot start

Dovecot配置完成

配置別名

編輯/etc/aliases

增加以下兩行內容：

postmaster: root
root: [email protected]

執行以下命令使新的別名生效，並重啓Postfix

newaliases
service postfix restart

測試Postfix和Dovecot

測試Postfix

使用telnet測試Postfix 

telnet localhost 25

連接到Postfix後輸入 

ehlo localhost

Postfix工作正常的話，輸出是

Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 plato.example.com ESMTP Postfix
ehlo localhost
250-plato.example.com
250-PIPELINING
250-SIZE 30720000
250-VRFY
250-ETRN
250-STARTTLS
250-AUTH PLAIN
250-AUTH=PLAIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN

測試Dovecot

使用telnet測試Dovecot 

telnet localhost pop3

Dovecot正常工作的話，輸出應該是

Trying 127.0.0.1...
Connected to localhost.localdomain.
Escape character is '^]'.
+OK Dovecot ready.

當Postfix和Dovecot測試都通過以後，我們接下來應該建立域和郵箱用戶了

建立域和郵箱用戶

在建立域之前，首先需要確認你的DNS服務器做了正確的MX解析，DNS做好之後，我們登錄MySQL插入域和郵箱用戶的記錄

mysql -u root -p

USE mail;
INSERT INTO domains (domain) VALUES ('example.com');
INSERT INTO users (email, password) VALUES ('[email protected]', ENCRYPT('password'));

測試MailBox

域和郵箱建立好之後，我們試着給用戶發送一封測試郵件 

mailx [email protected]

爲了確認是否收到郵件，我們進入郵箱目錄/home/vmail/example.com/sales/Maildir，輸入find命令 

find

應該能夠看到以下輸出

.
./dovecot-uidlist
./cur
./new
./new/1285609582.P6115Q0M368794.li172-137
./dovecot.index
./dovecot.index.log
./tmp

接下來可以使用Foxmail，Outlook之類的客戶端工具來收發郵件了。

排錯

在安裝過程中有問題，可以通過以下日誌文件來查看日誌，排查問題 

/var/log/maillog

/home/vmail/dovecot-deliver.log