这是将介绍使用postfix搭建邮件服务器：

a)    关闭sendmail 服务

$ /etc/init.d/sendmail stop

b)    安装Postfix 软件

$ yum install postfix

配置Postfix 启用SMTP认证

$ yum -y install cyrus-sasl*
$ /etc/init.d/saslauthd start

配置文件

$ vim /etc/postfix/main.cf
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
broken_sasl_auth_clients= yes
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
html_directory = no
# 设置 Postfix 服务监听的网络接口
inet_interfaces = localhost
 
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
 
# 设置可接收邮件的主机名称或域名
mydestination = $myhostname, localhost.$mydomain, localhost
 
# 设置运行 Postfix 服务的邮件主机的主机名、域名，如下所示：
mydomain = ops.com
myhostname = mail.ops.com
 
# 设置可转发哪些网络的邮件
mynetworks = 127.0.0.0/8
 
# 设置由本机寄出的邮件所使用的域名或主机名称
myorigin = $mydomain
 
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.6.6/README_FILES
 
# 设置可转发哪些网域
relay_domains = $mydestination
sample_directory = /usr/share/doc/postfix-2.6.6/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
 
# 配置SMTP信息
smtpd_client_restrictions = permit_sasl_authenticated
smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination
smtpd_sasl_auth_enable = yes
smtpd_sasl_local_domain = ''
smtpd_sasl_security_options = noanonymous
unknown_local_recipient_reject_code= 550

语法检查 && 开启服务

$ /usr/sbin/postconf –n
$ echo ‘127.0.0.1 localhost’ >/etc/hosts
$ postfix reload
$ /etc/init.d/postfix start