1. 介绍

将使用 CentOS 7 上的 BIND 9 配置主用（主）和辅助（备）DNS服务器。本文只介绍如何搭建主/从 DNS 服务器系统

2. 环境配置

2.1 主用DNS服务器

2.2 备用DNS服务器

3. BIND服务安装

yum install -y bind bind-utils

4. 主用 DNS 服务器的配置

  • BIND 的配置文件为”/etc/named.conf”，将其中如下内容进行修改：
listen-on port 53 { any;};
allow-query     { 0.0.0.0/0;};
  • 为了让配置文件保持整洁，我们新建一个本地解析文件”named.conf.local”，当然我们也可以修改”/etc/named.rfc1912.zones”文件来增加解析区域，因为这个文件是默认生效的，不过还是建议新建一个文件，这样看起来要清爽一些。将如下内容添加到”named.conf.local”文件中：
touch /etc/named.conf.local
zone "joinmedia.net" {
    type master;
    masterfile-format  text;
    file "/var/named/joinmedia.net";
    allow-transfer {172.21.110.253; };
    also-notify {172.21.110.253; };
};
zone "southbaytech.co" {
    type master;
    masterfile-format  text;
    file "/var/named/southbaytech.co";
    allow-transfer {172.21.110.253; };
    also-notify {172.21.110.253; };
};
zone "110.21.172.in-addr.arpa" {
    type master;
    masterfile-format  text;
    file "/var/named/110.21.172.in-addr.arpa";
    allow-transfer {172.21.110.253; };
    also-notify {172.21.110.253; };
};
zone "100.21.172.in-addr.arpa" {
    type master;
    masterfile-format  text;
    file "/var/named/100.21.172.in-addr.arpa";
    allow-transfer {172.21.110.253; };
    also-notify {172.21.110.253; };
};
  • 以上我们定义了4个DNS区域，2个域名正向解析，2个网段的反向解析。然后把文件写入到主配置。
echo 'include "/etc/named.conf.local";' >> /etc/named.conf
  • 分别添加4个区域的文件：
touch /var/named/joinmedia.net
touch /var/named/southbaytech.co
touch /var/named/110.21.172.in-addr.arpa
touch /var/named/100.21.172.in-addr.arpa
  • 以/var/named/joinmedia.net为例：
$TTL 1h
@       IN      SOA     joinmedia.net.    root.joinmedia.net. (
        2021041303      ; Serial YYYYMMDDnn
        24h             ; Refresh
        2h              ; Retry
        28d             ; Expire
        10m )            ; Minimum TTL
;Name Servers
@           IN  NS dns1
@           IN  NS dns2
dns1        IN  A  172.21.110.254
dns2        IN  A  172.21.110.253
conference  IN  A  192.168.0.142  
www         IN  A  192.168.0.219
;outside
jiawo       IN  A  115.239.233.26
  • 以100.21.172.in-addr.arpa为例：
$TTL 1h
@       IN      SOA     100.21.172.in-addr.arpa    root.joinmedia.net. (
        2021041219      ; Serial YYYYMMDDnn
        24h             ; Refresh
        1h              ; Retry
        28d             ; Expire
        10m )            ; Minimum TTL
@       IN      NS              dns1
@       IN      NS              dns2
dns1    IN      A               172.21.110.254
dns2    IN      A               172.21.110.253
;PTR Records
8   IN  PTR  mail.southbaytech.co
10  IN  PTR  ftp.southbaytech.co
  • 修改区域文件的拥有者
chown named:named /var/named/joinmedia.net
chown named:named /var/named/southbaytech.co
chown named:named /var/named/110.21.172.in-addr.arpa
chown named:named /var/named/100.21.172.in-addr.arpa

5. 备用 DNS 服务器的配置

  • BIND 的配置文件为”/etc/named.conf”，将其中如下内容进行修改：
listen-on port 53 { any;};
allow-query     { 0.0.0.0/0;};
  • 同样新建一个本地解析文件”named.conf.local”，添加以下内容
zone "joinmedia.net" {
    type slave;
    masters {172.21.110.254;};
    masterfile-format  text;
    file "/var/named/joinmedia.net";
};
zone "southbaytech.co" {
    type slave;
    masters {172.21.110.254;};
    masterfile-format  text;
    file "/var/named/southbaytech.co";
};
zone "110.21.172.in-addr.arpa" {
    type slave;
    masters {172.21.110.254;};
    masterfile-format  text;
    file "/var/named/110.21.172.in-addr.arpa";
};
zone "100.21.172.in-addr.arpa" {
    type slave;
    masters {172.21.110.254;};
    masterfile-format  text;
    file "/var/named/100.21.172.in-addr.arpa";
};

6. 启动主备DNS服务器

systemctl enable --now named.service