DNS的主从同步

原创已于 2025-04-20 15:29:31 修改 · 838 阅读

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#centos #运维 #linux

于 2025-04-20 15:16:34 首次发布

1.DNS域名解析原理

DNS（域名系统）是互联网中用于将域名转换为IP地址的分布式数据库系统，其核心原理是通过一系列的查询和响应机制，将用户输入的域名解析为对应的IP地址，从而实现对目标服务器的访问。这一过程涉及多个层次的域名服务器，包括根域名服务器、顶级域名服务器、权威域名服务器和本地DNS服务器等。

2. dns主从同步实现过程

2.1 先下载软件bind

1.主的虚拟机和从的虚拟机都需要下载软件。先把/mnt挂载到/dev/sr0，成功挂载后就可以下载bind软件。

[root@localhost ~]# mount /dev/sr0 /mnt
mount: /mnt: WARNING: source write-protected, mounted read-only.
[root@localhost ~]# yum install bind -y

2.如果不确定挂载情况的话，可以输入lsblk查看自己挂载成功与否，rom后面有/mnt则表明挂载成功。

[root@localhost ~]# lsblk
NAME          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sr0            11:0    1  9.8G  0 rom  /mnt
nvme0n1       259:0    0   50G  0 disk
├─nvme0n1p1   259:1    0  600M  0 part /boot/efi
├─nvme0n1p2   259:2    0    1G  0 part /boot
└─nvme0n1p3   259:3    0 48.4G  0 part
  ├─rhel-root 253:0    0 46.4G  0 lvm  /
  └─rhel-swap 253:1    0    2G  0 lvm  [SWAP]

3.软件安装完成后就打开

[root@localhost ~]# systemctl start named

2.2 主dns的配置：192.168.15.131

1.输入 vim /etc/named.conf ，进入后开始相关的配置。其中zone的相关部分可以输入vim /etc/named.rfc1912.zones进入到里面去复制，但相关的数据需要换成自己需要的。需要注意的是，allow-transfer{}，{}里面填入的是你需要转发的从的dns，修改完成后保存退出。监听的端口号可以填指定的，也可以填任何（any）。

options {
        listen-on port 53 { any; };
        directory       "/var/named";
        allow-query     { any; };
        allow-transfer {192.168.15.132 ;};
};

zone "li.com." IN {
        type master;
        file "named.li.com";

};
zone "15.168.192.in-addr.arpa" IN {
        type master;
        file "named.192.168.15.zone";
};


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

2. 资源记录文件通过/var/named/named.localhost模版拷贝修改

[root@localhost ~]# cp -a /var/named/named.localhost /var/named/named.li.com

[root@localhost ~]# cp -a /var/named/named.localhost /var/named/named.192.168.15.zone

3. [root@localhost ~]# vim /var/named/named.li.com ，进入修改配置。

$TTL 1D
@       IN SOA  @ xixi.admin. (
                                        1       ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
        NS      dns
dns     A       192.168.15.131
xixi    A       192.168.15.131
~
~

4.[root@localhost ~]# vim /var/named/named.192.168.15.zone，进入修改配置。

$TTL 1D
@       IN SOA  @ hehe.com. (
                                        0       ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
        NS      dns2.li.com.
dns2.li.com.    A       192.168.15.131
129    PTR   gggg.li.com.
130    PTR   gogo.li.com.
~
~

5.主dns的配置全部配完后，重启named服务使配置生效，然后再关闭防火墙。

[root@localhost ~]# systemctl  restart named
[root@localhost ~]# systemctl stop firewalld

2.3 从dns的配置：192.168.15.132

1.输入 vim /etc/named.conf ，进入后开始相关的配置。可以从主的配置文件里复制，但还需要修改一些数据。

options {
        listen-on port 53 { any; };
        directory       "/var/named";
        allow-query     { any; };
};

zone "li.com." IN {
        type slave;
        masters{192.168.15.131 ;};
        file "slaves/named.li.com";

};
zone "15.168.192.in-addr.arpa" IN {
        type slave;
        masters{192.168.15.131 ;};
        file "slaves/named.192.168.15.zone";
};

2.从dns的配置全部配完后，重启named服务使配置生效，然后再关闭防火墙。

[root@localhost ~]# systemctl  restart named
[root@localhost ~]# systemctl stop firewalld

2.4 测试

dns能解析出来，则代表测试成功。

[root@localhost ~]# nslookup xixi.li.com 192.168.15.131
[root@localhost ~]# nslookup xixi.li.com 192.168.15.132

[root@localhost ~]# nslookup xixi.li.com 192.168.15.131
Server:         192.168.15.131
Address:        192.168.15.131#53

Name:   xixi.li.com
Address: 192.168.15.131

[root@localhost ~]# nslookup xixi.li.com 192.168.15.132
Server:         192.168.15.132
Address:        192.168.15.132#53

Name:   xixi.li.com
Address: 192.168.15.131

[root@localhost ~]# host xixi.li.com 192.168.15.131
[root@localhost ~]# host xixi.li.com 192.168.15.132

[root@localhost ~]# host xixi.li.com 192.168.15.132
Using domain server:
Name: 192.168.15.132
Address: 192.168.15.132#53
Aliases:

xixi.li.com has address 192.168.15.131
[root@localhost ~]# host xixi.li.com 192.168.15.131
Using domain server:
Name: 192.168.15.131
Address: 192.168.15.131#53
Aliases:

xixi.li.com has address 192.168.15.131

2.5 增量同步实验

1.主

往 /var/named/named.li.com 和 /var/named/named.192.168.15.zone 中添加一行新的解析记录，序列号要比原名来的大点，配置完后重启生效（systemctl restart named）。

$TTL 1D
@       IN SOA  @ xixi.admin. (
                                        100     ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
        NS      dns
dns     A       192.168.15.131
xixi    A       192.168.15.131
wdwd    A       192.168.15.131

$TTL 1D
@       IN SOA  @ hehe.com. (
                                        100     ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
        NS      dns2.li.com.
dns2.li.com.    A       192.168.15.131
129    PTR   gggg.li.com.
130    PTR   gogo.li.com.
131    PTR   ogog.li.com.
132    PTR   jjjj.li.com.
~
~
~
~
~

2.从

从进行手动增量同步，同步完后也需要重启生效（systemctl restart named）。

[root@localhost ~]# rndc refresh  li.com       
zone refresh queued
[root@localhost ~]# rndc refresh 15.168.192.in-addr.arpa
zone refresh queued

3.测试

dns能解析出来代表测试成功。
[root@localhost ~]# nslookup wdwd.li.com 192.168.15.131
[root@localhost ~]# nslookup wdwd.li.com 192.168.15.132

[root@localhost ~]# nslookup wdwd.li.com 192.168.15.131
Server:         192.168.15.131
Address:        192.168.15.131#53

Name:   wdwd.li.com
Address: 192.168.15.131

[root@localhost ~]# nslookup wdwd.li.com 192.168.15.132
Server:         192.168.15.132
Address:        192.168.15.132#53

Name:   wdwd.li.com
Address: 192.168.15.131

[root@localhost ~]# host wdwd.li.com 192.168.15.131
[root@localhost ~]# host wdwd.li.com 192.168.15.132

[root@localhost ~]# host wdwd.li.com 192.168.15.132
Using domain server:
Name: 192.168.15.132
Address: 192.168.15.132#53
Aliases:

wdwd.li.com has address 192.168.15.131
[root@localhost ~]# host wdwd.li.com 192.168.15.131
Using domain server:
Name: 192.168.15.131
Address: 192.168.15.131#53
Aliases:

wdwd.li.com has address 192.168.15.131