主/从DNS

主从DNS的环境应用：1、负载均衡，缓解主DNS压力。

2、当主DNS挂了，DNS会正常工作、不会影响正常工作。

3、可以更快的相应客户的请求。

环境：拥有2台服务器，分别配置静态IP和安装rpm包

主DNS（rh_2):

[[email protected]_2 ~]# ifconfig |  head -2
   eth0      Link encap:Ethernet  HWaddr 52:54:02:AC:DE:C4
          inet addr:192.168.122.243  Bcast:192.168.122.255
       Mask:255.255.255.0
  [[email protected]_2 ~]# yum -y install bind bind-chroot caching-nameserver

从DNS（rh—3）

[[email protected]_3 ~]# ifconfig | head -2
eth0      Link encap:Ethernet  HWaddr 52:54:03:AC:DE:C4
          inet addr:192.168.122.3  Bcast:192.168.122.255  Mask:255.255.255.0
You have mail in /var/spool/mail/root
[[email protected]_3 ~]# yum -y install bind bind-chroot caching-nameserver

一:配置主DNS

1、编辑主配置文件

[[email protected]_2 ~]# cd /var/named/chroot/etc/
[[email protected]_2 etc]# cp -p named.caching-nameserver.conf named.conf
[[email protected]_2 etc]# vim named.conf 14 options {
 15         listen-on port 53 { 192.168.122.243; };    //监听本机
                                             192.168.122.243的NDS查询
 16         listen-on-v6 port 53 { ::1; };
 21         allow-transfer { 192.168.122.3; };     //授权从DNS
 27         allow-query     { any; };             //  允许所有客户端查询
 28         allow-query-cache { any; };
 37         match-clients      { any; };
 38         match-destinations { any; };

2、编辑DNS数据文件

[[email protected]_2 etc]# vim named.rfc1912.zones
[[email protected]_2 etc]# cat named.rfc1912.zones  | tail -4
zone "baidu.com" IN {
type master;
file "baidu.zone";
};

3、编辑本地区域数据文件

[[email protected]_2 etc]# cd /var/named/chroot/var/named/
[[email protected]_2 named]# cp -p named.local baidu.zone
[[email protected]_2 named]# vim baidu.zone
[[email protected]_2 named]# cat baidu.zone
$TTL86400
@       IN      SOA     baidu.com. root.baidu.com.  (
                                      2014050101 ; Serial
                                      28800      ; Refresh
                                      14400      ; Retry
                                      3600000    ; Expire
                                      86400 )    ; Minimum
        IN      NS      dns1.baidu.com.
        IN      NS      dns2.baidu.com.
dns2    IN      A       192.168.122.3
dns1    IN      A       192.168.122.243
www     IN      A       192.168.122.1
zhidao  IN      A       192.168.122.2

4、启用DNS服务

[[email protected]_2 named]# service named restart
[[email protected]_2 named]# chkconfig named on

二、配置从DNS

1、配置DNS主配置文件

[[email protected]_3 ~]# cd /var/named/chroot/etc/
[[email protected]_3 etc]# cp -p named.caching-nameserver.conf named.conf
[[email protected]_3 etc]# vim named.conf
 14 options {
 15         listen-on port 53 { 192.168.122.3; };
 27         allow-query     { any; };
 28         allow-query-cache { any; };
 37         match-clients      { any; };
 38         match-destinations { any; };

2、编辑DNS数据文件

[[email protected]_3 etc]# vim named.rfc1912.zones
[[email protected]_3 etc]# cat  named.rfc1912.zones  | tail -6
zone "baidu.com" IN {
type slave;                            //类型为从从DNS
file "slaves/baidu.zone";              //本地区域数据路径和名字
        masters { 192.168.122.243;};   //权威主DNS
};
[[email protected]_3 etc]# service named restart
[[email protected]_3 etc]# chkconfig named on
[[email protected]_3 etc]# cat  /var/named/chroot/var/named/slaves/baidu.zone
$ORIGIN .                            //当搭建成功后"slaves"下会增加文
                              件，数据与主DNS区域属于一致
baidu.comIN SOAbaidu.com. root.baidu.com. (
                            2014050101 ; serial
                            28800      ; refresh (8 hours)
                            14400      ; retry (4 hours)
                            3600000    ; expire (5 weeks 6 days 16 hours)
                             86400      ; minimum (1 day)
                             )
           NS        dns1.baidu.com.
$ORIG      IN        baidu.com.
......

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