前言

dns：domain name service(域名解析服务)提供域名解析，主要分为dns服务端的搭建和测试端测试两部分内容

一、基本信息

二、双向解析

实验环境：
客户端2台
10.4.17网段
1.1.1网段 		    %ifconfig ens160 1.1.1.30 netmask 255.255.255.0

服务端1台2个网段的ip
10.4.17.18
1.1.1.101		    %ifconfig ens160 1.1.1.101 netmask 255.255.255.0


在10.4.17网段的客户主机中
vim /etc/resolv.conf
nameserver 10.4.17.118

在1.1.1网段的客户主机中
vim /etc/resolv.conf
nameserver 1.1.1.101

配置方式：
cd /var/named/
cp -p westos.org.zone westos.org.inter
vim westos.org.inter         %编辑另一个只有网段不同的子配置文件
$TTL 1D
@	IN SOA	dns.westos.org. root.westos.org (
					0	; serial
					1D	; refresh
					1H	; retry
					1W	; expire
					3H )	; minimum
		NS	dns.westos.org.
dns		A	1.1.1.118
www		CNAME	hello.westos.org.
test	A	1.1.1.117
test	A	1.1.1.116
westos.com.	MX 1	1.1.1.115.	%mail exchanger 

cp -p /etc/named.rfc1912.zones  /etc/named.rfc1912.inters
vim /etc/named.rfc1912.inters       
zone "westos.org" IN {
	type master;
	file "westos.org.inter";   %更改文件指向
	allow-update { none; };
};

vim /etc/named.conf            %编写主配置文件
#zone "." IN {                 %注释该部分内容
##       type hint;
##       file "named.ca";
##};
#
##include "/etc/named.rfc1912.zones";
##include "/etc/named.root.key";


view localnet {
        match-clients { 192.168.0.0/24; };
        zone "." IN {
                type hint;
                file "named.ca";
        };
        include "/etc/named.rfc1912.zones";
};

view internet {
        match-clients { any; };
        zone "." IN {
                type hint;
                file "named.ca";
        };
        include "/etc/named.rfc1912.inters";
};
include "/etc/named.root.key";      
systemctl restart named 

测试方法：
分别在2个网段的主机中作同样域名的地址解析，得到的A记录不同

三、dns更新

dns基于ip地址的更新：
在dns中设定：
vim /etc/named.rfc1912.zones

zone "westos.org" IN {
        type master;
        file "westos.org.zone";
        allow-update { 10.4.17.100; };		  %允许指定客户端更新westos域
        also-notify { 10.4.17.106; };
};
测试：
在10.4.17.100
[root@node1 ~]# nsupdate 
> server 10.4.17.118
> update add hello.westos.org 86400 A 10.4.17.119	%新增A记录
> send 
> update delete hello.westos.org			  %删除A记录
> send 

dns基于key更新的方式:
dnssec-keygen -a HMAC-SHA256 -b 128 -n HOST westos
cp -p /etc/rndc.key /etc/wesots.key
vim /etc/wesots.key
key "westos" {
	algorithm hmac-sha256;
	secret "SB1tQcLaWeroU9lGW21zeA==";
};

vim /etc/named.conf
43 include "/etc/wesots.key";
vim /etc/named.rfc1912.zones
zone "westos.org" IN {
        type master;
        file "westos.org.zone";
        allow-update { key westos; };
        also-notify { 10.4.17.106; };
};

systemctl restart named 

[root@node1 ~]# nsupdate -k /mnt/Kwestos.+163+26695.private 
> server 10.4.17.118
> update add hello.westos.org 86400 A 10.4.17.120
> send 
> quit

四、ddns（dhcp+dns）

选择一台主机作为dhcp服务器，可以选择dns服务器：
vim /etc/dhcp/dhcpd.conf        %编辑此配置文件，将其作为dhcp服务器
dnf instsall dhcp-server -y
vim /etc/dhcpd/dhcpd.conf
# dhcpd.conf
#
# Sample configuration file for ISC dhcpd
#

# option definitions common to all supported networks...
option domain-name "westos.com";
option domain-name-servers 192.168.0.20;

default-lease-time 600;
max-lease-time 7200;

# Use this to enble / disable dynamic dns updates globally.
ddns-update-style interim;    %开启为网络更新模式（interim)

# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
#authoritative;

# Use this to send dhcp log messages to a different log file (you also
# have to hack syslog.conf to complete the redirection).
log-facility local7;

# No service will be given on this subnet, but declaring it helps the 
# DHCP server to understand the network topology.


# This is a very basic subnet declaration.

subnet 10.4.17.0 netmask 255.255.255.0 {
  range 10.4.17.190 10.4.17.200;
}

key westos {
         algorithm hmac-sha256;
         secret SB1tQcLaWeroU9lGW21zeA==;
       };

zone westos.org. {
	primary 127.0.0.1;      %当dns和dhcp服务器为同一台主机时，这里可以写127.0.0.1本地回环接口，如果不是则需要写dns服务器ip
	key westos;
}

五、相关操作：