我們現在要安裝一個postfix，要求其支持web mail，並安裝web mail實現郵箱的註冊、郵件的發送接收。
一、安裝配置DNS
參考：DNS的快速配置和安裝
未完待續：
二、安裝postfix前的準備工作
1.關閉sendmail
service sendmail stop
chkconfig sendmail off
2.安裝編譯環境（工具）
安裝以下開發所用到的rpm包組：
Development Libraries
Development Tools
Legacy Software Development
X Software Development
yum -y groupinstall "Development Libraries" "Development Tools" "Legacy Software Development" "X Software Development"
3.安裝所需的rpm包
包括：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 -y 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
4.啓動mysql數據庫
service mysqld start
chkconfig mysqld on
5.啓動saslauthd服務
service saslauthd start
chkconfig saslauthd on
準備工作完成
三、安裝配置postfix
1.下載並解壓postfix (可以在官網www.postfix.org下載)
tar xf postfix-2.6.5.tar.gz
2.添加用戶和組
groupadd -g 2525 postfix
groupadd -g 2526 postdrop
useradd -g postfix -u 2525 -s /sbin/nologin -M postfix
useradd -g postdrop -u 2526 -s /sbin/nologin -M postdrop
2.編譯安裝
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
3.生成別名二進制文件，這個步驟如果忽略，會造成postfix效率極低：
Newaliases
4.編輯配置文件main.cf
cd /etc/postfix
cp main.cf main.cf.bak 備份main.cf
vim main.cf
修改以下幾項爲您需要的配置
myhostname = mail.zsl.com
myorigin = zsl.com
mydomain = zsl.com
inet_interfaces = all
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mynetworks = 192.168.19.0/24, 127.0.0.0/8
5.啓動postfix
postfix start
6.拷貝一個已經寫好的 postfix 到 /etc/init.d/postfix並啓動postfix
chomd +x /etc/init.d/postfix
chkconfig --add postfix
chkconfig postfix on
OK！Postfix安裝完成了。
四、爲postfix開啓基於cyrus-sasl的認證功能
1.驗證postfix是否支持cyrus風格的sasl認證，如果您的輸出爲以下結果，則是支持的：
/usr/local/postfix/sbin/postconf -a
cyrus
dovecot
2.編輯配置文件main.cf
vim /etc/postfix/main.cf
添加以下內容：
############################CYRUS-SASL############################
broken_sasl_auth_clients = yes
smtpd_recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject_invalid_h ostname,reject_non_fqdn_hostname,reject_unknown_sender_domain,reject_non_fqdn_sende r,reject_non_fqdn_recipient,reject_unknown_recipient_domain,reject_unauth_pipelining,reje ct_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = $myhostname
smtpd_sasl_security_options = noanonymous
smtpd_sasl_application_name = smtpd
smtpd_banner = Welcome to our $myhostname ESMTP,Warning: Version not Available!
3.編輯/usr/lib/sasl2/smtpd.conf
vim /usr/lib/sasl2/smtpd.conf
添加如下內容：
pwcheck_method: saslauthd
mech_list: PLAIN LOGIN
4.讓postfix重新加載配置文件
/usr/sbin/postfix/sbin/postfix reload
OK！現在postfix可以使用cyrus-sasl認證了。
五、安裝Courier authentication library
1.下載並解壓courier-authlib-0.62.4.tar.bz2
tar jxvf courier-authlib-0.62.4.tar.bz2
2.編譯安裝
cd courier-authlib-0.62.4
./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
3.修改文件權限
chmod 755 /usr/local/courier-authlib/var/spool/authdaemon
4.修改配置文件/etc/authdaemonrc cp、/etc/authmysqlrc
cp /etc/authdaemonrc.dist /etc/authdaemonrc
cp /etc/authmysqlrc.dist /etc/authmysqlrc
修改/etc/authdaemonrc 文件
authmodulelist="authmysql"
authmodulelistorig="authmysql"
daemons=10
編輯/etc/authmysqlrc 爲以下內容，其中2525，2525 爲postfix 用戶的UID和GID。
MYSQL_SERVER
MYSQL_PORT 3306 (指定你的mysql監聽的端口，這裏使用默認的3306)
MYSQL_USERNAME extmail (這時爲後文要用的數據庫的所有者的用戶名)
MYSQL_PASSWORD extmail (密碼)
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)
5.配置/etc/init.d中加入courier-authlib並開機啓動
cp courier-authlib.sysvinit /etc/init.d/courier-authlib
chmod 755 /etc/init.d/courier-authlib
chkconfig --add courier-authlib
chkconfig courier-authlib on
6.編輯默認庫文件路徑，並重新引導
vim /etc/ld.so.conf.d/courier-authlib.conf
寫入
/usr/local/courier-authlib/lib/courier-authlib
ldconfig -v
7.啓動服務
service courier-authlib start
8.新建虛擬用戶郵箱所在的目錄，並將其權限賦予postfix用戶：
mkdir –pv /var/mailbox
chown –R postfix /var/mailbox
9.接下來重新配置SMTP 認證，編輯 /usr/lib/sasl2/smtpd.conf ，確保其爲以下內容：
pwcheck_method: authdaemond
log_level: 3
mech_list:PLAIN LOGIN
authdaemond_path:/usr/local/courier-authlib/var/spool/authdaemon/socket
六、讓postfix支持虛擬域和虛擬用戶
1.編輯/etc/postfix/main.cf，添加如下內容：
########################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源碼目錄下docs目錄中的extmail.sql和init.sql建立數據庫：
tar zxvf extman-1.1.tar.gz
cd extman-1.1/docs
mysql -u root -p <extmail.sql
mysql -u root -p <init.sql
cp mysql* /etc/postfix/
3.授予用戶extmail訪問extmail數據庫的權限
mysql> GRANT all privileges on extmail.* TO extmail@localhost IDENTIFIED BY 'extmail';
mysql> GRANT all privileges on extmail.* TO [email protected] IDENTIFIED BY 'extmail';
FLUSH PRIVILEGES;
說明：啓用虛擬域以後，需要取消中心域，即註釋掉myhostname, mydestination, mydomain, myorigin幾個指令；當然，你也可以把mydestionation的值改爲你自己需要的。
未完待續……
七、配置dovecot
1.編輯配置文件dovecot.conf
vim /etc/dovecot.conf
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
}
2.編輯dovecot-mysql.conf
vim /etc/dovecot-mysql.conf
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'
3.啓動dovecot服務：
service dovecot start
chkconfig dovecot on