1.dns快取記憶體服務搭建
伺服器：yum install bing.x86_64 安裝dns服務

設定ip及其閘道器

     vim /etc/named.conf      配置dns服務檔案
           11  listen-on port 53 {any;};  開啟任意服務端網路介面dns埠
           17  allow-query  {any;};  允許所有主機訪問這臺dns伺服器
               forwarders {114.114.114.114;};
           33  dnssec-validation no    關閉網路認證
 

       systemctl restart named  重啟dns服務
           vim /etc/resolv.conf   配置地址解析檔案
            nameserver 114.114.114.114  本機不知時訪問114.114.114.114

  客戶機：vim /etc/resolv.conf   
             nameserver 172.25.254.107

   dig www.baidu.com 查詢baidu的ip（第二次訪問時速度更快，因為訪問一次後，地址解析的檔案快取到本機上）

2.dns的正向解析：（域名—>ip）

          vim /etc/named.conf
             刪除forwarders {114.114.114.114;};行
          cd /var/named/
          cp -p named.localhost westos.com.zone

  vim westos.com.zone

   vim /etc/named.rfc1912.zones
       zone "westos.com" IN {
           type master;
           file "westos.com.zone";
          allow-update
 
 { none; };
   };

 dig hello.westos.com

（3）迴圈輪叫：

  vim westos.com.zone

     dig www.westos.com

3.dns反向解析（ip—–>域名）：

   vim /etc/named.rfc1912.zones     
         zone "254.25.172.in-addr.arpa" IN {
             type master;
            file "westos.com.ptr";
            allow-update { none; };
       };

   cd /var/named/
   cp -p named.loopback westos.com.ptr
   vim westos.com.ptr

   systemctl restart named重啟dns服務
   dig -x 172.25.254.111(-x 反向解析)

4.內外網的搭建(多向解析)

  cp -p /etc/named.rfc1912.zones  /etc/named.rfc1912.inter
   vim /etc/named.rfc1912.inter
     zone "westos.com" IN {
        type master;
        file "westos.com.inter";
        allow-update { none; };
     };

   cp -p westos.com.zone  westos.com.inter
   vim westos.com.inter

  vim /etc/named.conf
    view  localnet {
        match-clients { 172.25.254.107; };
        zone "." IN{
                type hint;
                file "named.ca";
        };
        include "/etc/named.rfc1912.zones";
    };
    view  inter {
        match-clients { any; };
        zone "." IN{
                type hint;
                file "named.ca";
        };
          include "/etc/named.rfc1912.inter";
    };

   systemctl restart named
   dig www.westos.com

5.dns機群(輔助dns)：
serve中： 安裝並設定dns的配置檔案與前面相同

    yum install bind
    systemctl restart firewalld
    vim /etc/named
           11  listen-on port 53 {any;};  開啟任意服務端網路介面dns埠
           17  allow-query  {any;};  允許所有主機訪問這臺dns伺服器
           33  dnssec-validation no    關閉網路認證
           systemctl restart named  重啟dns服務

   vim /etc/named.rfc1912.zones
       zone "westos.com" IN {
          type slave;                    輔助dns
          masters { 172.25.254.107; };  在172.25.254.107上下載westos.com.zone檔案到slaves中
          file "slaves/westos.com.zone";
          allow-update { none; };
       };

    vim /etc/resolv.conf
      nameserver 172.25.254.107

desktop中：

    vim /etc/named.rfc1912.zones
       zone "westos.com" IN {
          type master;
          file "westos.com.zone";
          allow-update { none; };
          also-notify { 172.25.254.207; };    同步到的主機ip，可多個，中間用空格間隔
      };

    vim /var/name/westos.com.zone

dig www.westos.com

6.dns 更新
實驗前備份/var/named/westos.com.zone
selinux為disabled

dns伺服器：

   vim /etc/named.rfc1912.zones
       zone "westos.com" IN {
          type master;
          file "westos.com.zone";
          allow-update { 172.25.254.7; };  允許更新的主機ip
          also-notify { 172.25.254.207; };
       };

   systemctl restart named
   chmod 770 /var/named/  許可權

可更新的主機：

      nsupdate  新增更新
       >server 172.25.254.107
       >update add test.westos.com 86400 A 172.25.254.119 
       >send

 vim /var/named/westos.com.zone

        nsupdate 刪除更新
         >server 172.25.254.107
         >update delete test.westos.com 
         >send

7.key方式解析:

     dnssec-keygen -a HMAC-MD5 -b 128 -n HOST westos
     cat Kwestos.+157+14628.private
     cat Kwestos.+157+14628.key

   cp /etc/rndc.key  /etc/westos.key -p
     systemctl restart named

    vim /etc/westos.key
        key "westos" {
          algorithm hmac-md5;
          secret "aclcI8b+xmJOpOhrpDsE7Q==";
      };

   vim /etc/named.conf
     include "/etc/westos.key";

     vim /etc/named.rfc1912.zone
         zone "westos.com" IN {
          type master;
          file "westos.com.zone";
          allow-update { key westos; };
          also-notify { 172.25.254.207; };
       };

     systemctl restart named
     scp Kwestos.+157+14628.* root@172.25.254.7:/mnt/

       dig www.westos.com

8.動態域名解析（花生殼）：
安裝dhcpd

     vim /etc/dhcp/dhcpd.conf
     cp /usr/share/doc/dhcp*/dhcpd.conf.example /etc/dhcp/dhcpd.conf 
     systemctl restart named
     systemctl restart dhcpd
     vim /etc/dhcp/dhcpd.conf
       option domain-name "westos.com";
option domain-name-servers 172.25.254.107;

default-lease-time 600;
max-lease-time 7200;
ddns-update-style interim; 開啟dhcp動態域名更新服務
log-facility local7;

   subnet 172.25.254.0 netmask 255.255.255.0 {
       range 172.25.254.215  172.25.254.220;
       option routers 172.25.254.107;
      }

   key westos{
            algorithm hmac-md5;
            secret aclcI8b+xmJOpOhrpDsE7Q==;
     };
      zone westos.com. {
          primary 127.0.0.1;
          key westos;
     }
    systemctl restart dhcpd

server虛擬機器中：

      hostnamectl set-hostname linux.westos.com
      systemctl restart network

      dig linux.westos.com

重新整理後server重新獲得ip地址，dig linux.westos.com，檢視地址是不是會更新