[root@localhost ~]# rpm -qa | grep postfix

[root@localhost ]# yum install -y postfix

Loaded plugins: fastestmirror, refresh-packagekit, security                                                 

Complete!

[root@localhost]#

[root@localhost ~]# gedit /etc/postfix/main.cf

mydomain = david.cn      //dns中的域名

myhostname = mailsrv.david.cn  //dns中的域名

mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain

inet_interfaces = all   //允许处理所有网路信息

inet_protocols = all    //允许ipv4和ipv6

mynetworks = 192.168.0.0/24, 127.0.0.0/8     //允许接入的ip段

[root@localhost ~]# gedit /etc/sysconfig/iptables

-A INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j ACCEPT

[root@localhost ~]# service iptables restart

iptables：将链设置为政策 ACCEPT：filter nat                [确定]

iptables：清除防火墙规则：                                 [确定]

iptables：正在卸载模块：                                   [确定]

iptables：应用防火墙规则：                                 [确定]

iptables：载入额外模块：nf_conntrack_ftp                   [确定]

[root@localhost ~]# service postfix start

启动postfix：                                             [确定]

[root@localhost ~]#

[root@localhost ~]# telnet 192.168.0.113 25    //ip是本机地址，25是端口号

Trying 192.168.0.113...

Connected to 192.168.0.113.

Escape character is '^]'.

220 mailsrv.david.cn ESMTP Postfix

[root@localhost ~]# mail david     //给david发信，确保此用户存在Linux系统中。发信人是当前登录的用户root

Subject: test04       //标题

hello david           //内容

.                       //结束

EOT

[root@localhost ~]# mail -u david      //查看用户david的信件

Heirloom Mail version 12.4 7/29/08.  Type ? for help.

"/var/mail/david": 5 messages 1 new

    1 root                  Thu Aug 16 17:07  21/692   "test"

    2 root                  Thu Aug 16 17:08  20/631   "test"

    3 root                  Thu Aug 16 17:10  20/602   "test"

    4 root                  Fri Aug 17 08:15  20/570   "test3"

>N  5 root                  Fri Aug 17 09:46  18/539   "test04"    //此信件是刚才收到的，由root用户发出

&