为什么要搭建dns服务器，dns的作用是寻址，方便寻址。

Dns在企业中的作用：

1、如果使用ip，一个企业有几百个ip或者上千个ip的情况，就不方便记忆了。

2、当做机房迁移或者数据迁移ip更换的时候，避免代码因为ip变化带来的发版麻烦。甚至出现业务故障。

环境

系统：centos7

主机ip

192.168.201.6 主dns

192.168.201.4 从dns

一、单机搭建

关闭防火墙

systemctl stop firewalld # 关闭

systemctl disable firewalld # 取消开机启动

vi /etc/selinux/config，

将SELINUX=enforcing改为SELINUX=disabled

2、 bind安装

yum install bind

配置主配置文件

# cat /etc/named.conf

options {

listen-on port 53 { any; };

// listen-on-v6 port 53 { ::1; };

directory "/var/named";

dump-file "/var/named/data/cache_dump.db";

statistics-file "/var/named/data/named_stats.txt";

memstatistics-file "/var/named/data/named_mem_stats.txt";

recursing-file "/var/named/data/named.recursing";

secroots-file "/var/named/data/named.secroots";

allow-query { any; }; #localhost修改为any

recursion yes; #递归查询

dnssec-enable no; #yes修改为no

dnssec-validation no;

/* Path to ISC DLV key */

// bindkeys-file "/etc/named.root.key"; #注释

// managed-keys-directory "/var/named/dynamic"; #注释

// pid-file "/run/named/named.pid";

// session-keyfile "/run/named/session.key";

};

logging {

channel default_debug {

file "data/named.run";

severity dynamic;

};

};

zone "." IN {

type hint;

file "named.ca";

};

include "/etc/named.rfc1912.zones";

include "/etc/named.root.key";

# cat /etc/named.rfc1912.zones

zone "localhost.localdomain" IN {

type master;

file "named.localhost";

allow-update { none; };

};

zone "localhost" IN {

type master;

file "named.localhost";

allow-update { none; };

};

zone "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa" IN {

type master;

file "named.loopback";

allow-update { none; };

};

zone "1.0.0.127.in-addr.arpa" IN {

type master;

file "named.loopback";

allow-update { none; };

};

zone "0.in-addr.arpa" IN {

type master;

file "named.empty";

allow-update { none; };

};

zone "wumart.com" IN {

type master;

file "wolf.com.zone";

};

zone "201.168.192.in-addr.arpa" IN {

type master;

file "wolf.201.168.192";

};

4、配置正向区域和方向区域

然后正向主要配置www 对ip A记录和mx记录，当然也可以有别名cname配置

vi /var/named/wolf.com.zone

vi /var/named/wolf.201.168.192

语法检查

named-checkconf

named-checkzone wolf.com wolf.com.zone

named-checkzone "201.168.192.in-addr.arpa" wolf.201.168.192

6、重启

service named restart

查看服务是否启动

7、测试

ping

dig

正向

反向

到这里单机搭建就完成了。

二、dns主从搭建

按照上面的步骤在192.168.201.4安装bind

修改主dns配置

在named.conf中加入

allow-transfer { 192.168.201.4; };

在正向文件和反向文件中加入

IN NS ns2.wolf.com.

ns2 IN NS 192.168.201.4

重启named

Service named restart

2、下载named.conf和named.rfc1912.zones文件

3、上传named.conf和named.rfc1912.zones文件到192.168.201.4

[root@rancher etc]# cat /etc/named.rfc1912.zones

zone "wolf.com" IN {

type slave;

file "slaves/wolf.com.zone";

masters {192.168.201.6;};

};

zone "201.168.192.in-addr.arpa" IN {

type slave;

file "slaves/wolf.201.168.192";

masters {192.168.201.6;};

}

4、重启服务

# service named restart

Redirecting to /bin/systemctl restart named.service

检查文件是否同步

测试解析

5、同步测试

主dns上添加一条test.wolf.com

重启服务

service named reload

同步成功了

三、主从切换搭建

企业内部一般使用keepalived+bind实现自动切换，或者lvs+keepalived+bind实现负载均衡。

有兴趣的朋友一起讨论。