1 前言

一个问题，一篇文章，一出故事。
笔者一个邮件投递服务需要邮件MX记录的配合，于是整理此文。

2 最佳实践

2.1 DNS服务环境

如何实现DNS内外解析分离？

2.2 配置MX记录

2.2.1 创建配置

vim /var/named/sae.com.hk.internal.zone

创建如下记录，

#...
mail01          IN A            10.168.0.125
mail02          IN A            10.168.0.126
mail01          IN MX        10 mail01.cmdschool.org.
mail02          IN MX        10 mail02.cmdschool.org.

2.2.2 检查配置文件

named-checkconf /etc/named.conf
named-checkconf -t /var/named/chroot/ /etc/named.conf

2.2.3 重新启动服务使配置生效

In dnsSer0[1,2]

systemctl restart named-chroot.service

2.2.4 验证配置

In client01

nslookup
> server 10.168.0.60
Default server: 10.168.0.60
Address: 10.168.0.60#53
> set type=mx
> mail01.cmdschool.org
Server:         10.168.0.60
Address:        10.168.0.60#53

mail01.cmdschool.org       mail exchanger = 10 mail01.cmdschool.org.
> mail02.cmdschool.org
Server:         10.168.0.60
Address:        10.168.0.60#53

mail02.cmdschool.org       mail exchanger = 10 mail02.cmdschool.org.
>