CentOS使用Postfix发送邮件

1）配置hosts映射

[ ~]# ifconfig ens33
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.2.3.11  netmask 255.255.255.0  broadcast 10.2.3.255
        inet6 fe80::20c:29ff:fec1:6505  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:c1:65:05  txqueuelen 1000  (Ethernet)
        RX packets 8665  bytes 10401537 (9.9 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1752  bytes 217252 (212.1 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[ ~]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
10.2.3.11	mds.com
10.2.3.11	mail.mds.com

2）安装Postfix与Mailx工具

[ ~]# yum -y install postfix mailx
[ ~]# systemctl start postfix
[ ~]# systemctl enable postfix
[ ~]# netstat -anput | grep 25
tcp        0      0 0.0.0.0:25              0.0.0.0:*               LISTEN      1820/master

3）定义Postfix配置文件

[ ~]# vim /etc/postfix/main.cf
myhostname = mail.mds.com
mydomain = mds.com
myorigin = $mydomain
inet_interfaces = all
mydestination = $myhostname,$mydomain

以下是以上选项的解释：
===================
myhostname	　　 　　　 #邮件系统的主机名
mydomain 	　　 　　　 #邮件系统的域名
myorigin 		       #从本机发出邮件时所用的名称
inet_interfaces	       #监听的网卡接口
mydestination	       #可接收邮件的主机名或域名

4）申请163邮件证书

[ ~]# mkdir /root/.certs
[ ~]# echo -n | openssl s_client -connect smtp.163.com:465 | sed -ne ‘/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p‘ > ~/.certs/163.crt
[ ~]# certutil -A -n "GeoTrust Global CA" -t "C,," -d ~/.certs -i ~/.certs/163.crt
[ ~]# certutil -A -n "GeoTrust SSL CA" -t "C,," -d ~/.certs -i ~/.certs/163.crt
[ ~]# certutil -L -d /root/.certs
[ ~]# certutil -A -n "GeoTrust SSL CA - G3" -t "Pu,Pu,Pu" -d ~/.certs/ -i ~/.certs/163.crt

5）借用163邮箱发送邮件

[ ~]# vim /etc/mail.rc
set ssl-verify="ignore"
set smtp-auth="login"
set from=""
set smtp="smtps://smtp.163.com:465"
set smtp-auth-user=""
set smtp-auth-password="123456"
set nss-config-dir="/root/.certs"

6）重启服务并发送测试邮件

[ ~]# systemctl restart postfix
[ ~]# echo "This is a test mail" | mail -s ‘邮件测试‘

7）确认接收邮件

【只是为了打发时间】