配置DNS

mailwestos.example.com

vim /etc/named.rfc1912.zones

  zone "westos.com" IN {

         type master;

         file "westos.com.zone";

        allow-update { none; };

  };

  zone "linux.com" IN {

          type master;

         file "linux.com.zone";

         allow-update { none; };

  };

cp -p named.localhost westos.com.zone

vim /var/named/westos.com.zone 

cp -p westos.com.zone linux.com.zone

vim /var/named/linux.com.zone 

systemctl restart named

systemctl stop firewalld

vim /etc/postfix/main.cf 

maillinux.example.com

    

●别名发送:

linux.com 主机向 westos.com主机发送邮件，使用别名发送

vim /etc/aliases

    vim /etc/moreusers 

        root

        student

 postalias /etc/aliases

 systemctl restart postfix.service 

4.出站地址伪装

server (westos.com)主机:

vim /etc/postfix/generic 

postmap /etc/postfix/generic

postconf -d | grep generic 会出来一段字符,选择最后的一行字符(如下)，进行复制:

smtp_generic_maps =

postconf -e "smtp_generic_maps = hash:/etc/postfix/generic" ##此处用到上条语句复制的字符

systemctl restart postfix.servic

5.检测25端口

下载 yum install telnet -y

250 2.0.0 Ok: queued as 38E0C17E849

quit ##退出telnet

221 2.0.0 Bye

Connection closed by foreign host.