八、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风格的sasl认证，如果您的输出为以下结果，则是支持的：
# /usr/local/postfix/sbin/postconf -a
cyrus
dovecot
#vim /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_sasl_application_name = smtpd
smtpd_banner = Welcome to our $myhostname ESMTP,Warning: Version not Available!
#vim /usr/local/lib/sasl2/smtpd.conf(可能是vim /usr/ lib/sasl2/smtpd.conf)
添加如下内容：
pwcheck_method: saslauthd
mech_list: PLAIN LOGIN
让postfix重新加载配置文件
#/usr/local/postfix/sbin/postfix reload
# telnet localhost 25
Trying 127.0.0.1...
Connected to localhost.localdomain (127.0.0.1).
Escape character is '^]'.
220 Welcome to our mail.benet.org ESMTP,Warning: Version not Available!
ehlo mail.benet.org
250-mail.benet.org
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-AUTH PLAIN LOGIN
250-AUTH=PLAIN LOGIN （请确保您的输出以类似两行）
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
九、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、添加为支持虚拟域和虚拟用户所用到的配置文件
编辑/etc/postfix/mysql_virtual_alias_maps.cf ，添加如下内容：
user = extmail
password = extmail
hosts = localhost
dbname = extmail
table = alias
select_field = goto
where_field = address
编辑/etc/postfix/mysql_virtual_domains_maps.cf ，添加如下内容：
user = extmail
password = extmail
hosts = localhost
dbname = extmail
table = domain
select_field = description
where_field = domain
编辑/etc/postfix/mysql_virtual_mailbox_limit_maps.cf ，添加如下内容：
user = extmail
password = extmail
hosts = localhost
dbname = extmail
table = mailbox
select_field = quota
where_field = username
编辑/etc/postfix/mysql_virtual_mailbox_maps.cf ，添加如下内容：
user = extmail
password = extmail
hosts = localhost
dbname = extmail
table = mailbox
select_field = maildir
where_field = username
说明：
1、这里用到的数据库及用户的建立可以后文中的extmail说明部分来实现，您可以参照那一部分来理解这里指定的数据库及其用户名等；
2、以上新建文件亦可以从extman安装文件中获得，您也可以由此不用手动输入；
3、虚拟用户邮箱目录我这里沿用了/var/mailbox，你可以指定为别的目录，比如常见到的/var/spool/mail，或者/home/domains等；但如果这里做了修改，请在后文中用到时作了相应的修改；
十、安装Courier authentication library
# tar jxvf courier-authlib-0.61.0.tar.bz2
# cd courier-authlib-0.61.0
#./configure
--prefix=/usr/local/courier-authlib
--sysconfdir=/etc
--without-authpam
--without-authldap
--without-authpwd
--without-authshadow
--without-authvchkpw
--without-authpgsql
--with-authmysql
--with-mysql-libs=/usr/local/mysql/lib/mysql
--with-mysql-includes=/usr/local/mysql/include/mysql
--with-redhat
--with-authmysqlrc=/etc/authmysqlrc
--with-authdaemonrc=/etc/authdaemonrc
CFLAGS="-march=i686 -O2 -fexpensive-optimizations"
CXXFLAGS="-march=i686 -O2 -fexpensive-optimizations"
(./configure --prefix=/usr/local/courier-authlib --sysconfdir=/etc --without-authpam --without-authldap --without-authpwd --without-authshadow --without-authvchkpw --without-authpgsql --with-authmysql --with-mysql-libs=/usr/local/mysql/lib/mysql --with-mysql-includes=/usr/local/mysql/include/mysql --with-redhat --with-authmysqlrc=/etc/authmysqlrc --with-authdaemonrc=/etc/authdaemonrc CFLAGS="-march=i686 -O2 -fexpensive-optimizations" CXXFLAGS="-march=i686 -O2 -fexpensive-optimizations")
# make
# make install
# make install-migrate
# make install-configure
# 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 (这时为后文要用的数据库的所有者的用户名)
MYSQL_PASSWORD extmail (密码)
MYSQL_SOCKET /tmp/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/',maildir)
MYSQL_NAME_FIELD name
MYSQL_MAILDIR_FIELD concat('/var/mailbox/',maildir)
# 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
#echo "/usr/local/courier-authlib/lib/courier-authlib" >> /etc/ld.so.conf
# ldconfig -v
# service courier-authlib start (启动服务)
