###########DNS的集群#############
1.做此实验之前最好把你之前在/etc/named.conf写入的东西注释掉，再重启下named服务
2.在主DNS的虚拟机中
vim /etc/named.rfc1912.com.zones
在第29行加上：also-notify {172.25.254.217;};
systemctl restart named
3.在辅DNS的虚拟机中
vim /etc/resolv.conf
写入：nameserver 172.25.254.117
vim /etc/named.rfc1912.com.zones
写入：zone "westos.com" IN {
type slave;
master {172.25.254.117;};
file "slaves/westos.com.zone";
allow-update {none;};
};
3.再到主DNS虚拟机中
vim /var/named/westos.com.zone
修改里面网址所对应的ip，再到辅虚拟机中dig网址，查看是否同步更新了
在主虚拟机中dig www.westos.com
在辅虚拟机中dig.westos.com
########DNS的更新####
在主DNS虚拟机中：
1.cp -p westos.com.zone /mnt ###备份此文件
vim /etc/named.rfc1912.zones
将第28行改为：allow-update {172.25.254.17;}; ####写入你进行更新操作的主机ip(真机)
systemctl restart named
ll -d /var/named
chmod 770 /var/named
2.在真机中：
[kiosk@foundation17 Desktop]$ nsupdate
> server 172.25.254.117
> update add test.westos.com 86400 A 172.25.254.111 ###添加test.westos.com
> send
3.分别在主DNS虚拟机和辅DNS虚拟机中
dig test.westos.com ###查看test.westos.com是否添加成功
主虚拟机：
辅虚拟机：
4.在主DNS虚拟机中：
systemctl restart named
cat /var/named/westos.com.zone ###发现已经改变
5.在真机中：
> server 172.25.254.117
> update delete test.westos.com ####删除test.westos.com
> send
6.在主DNS虚拟机中
cd /var/named
rm -fr /var/named/westos.com.zone*
cp -p /mnt/westos.com.zone . ###恢复原文件
######DNS加密更新#####
在主DNS虚拟机中：
cd /mnt
ls
dnssec-keygen -a HMAC-MD5 -b 128 -n HOST xbw
ls
cat Kxbw.+157+40688.private
cp -p /etc/rndc.key /etc/xbw.key
vim /etc/xbw.key
vim /etc/named.conf
在43行加入：include "/etc/xbw.key";
vim /etc/named.rfc1912.zones
将此行修该为allow-update {key xbw;};
systemctl restart named
scp Kxbw.+157+40688.* [email protected]:/mnt
dig zq.westos.com
在辅DNS虚拟机中：
cd /mnt
ls
nsupdate -k Kxbw.+157+40688.private
> server 172.25.254.117
> update add zq.westos.com 86400 A 172.25.254.222
> send
###############动态域名解析########
1.在desktop虚拟机中
yum install dhcp -y
cp /usr/share/doc/dhcp-4.2.5/dhcpd.conf.example /etc/dhcp/dhcpd.conf
vim /etc/dhcp/dhcpd.conf
systemctl restart dhcpd
cd /var/named
2.在server虚拟机中
hostnamectl set-hostname linux.westos.com
vim /etc/sysconfig/network-scripts/ifcfg-eth0
将BOOTPROTO改成dhcp
systemctl restart network
ifconfig
dig linux.westos.com
