#####DNS高速缓存###
1.服务端
yum install bind -y ###安装bind软件
rpm -qc bind ###查看bind的配置文件是什么
主配置文件:vim /etc/named.conf
修改:第11行 listen-on port 53 {any;};
第17行 allow-query {any;};
第18行写入:forwarders {114.114.114.114;};
第32行 dnssec-validation no;
systemctl restart named
vim /etc/resolv.conf
写入:nameserver 172.25.254.117
systemctl restart network
dig www.baidu.com
访问者得到答案的时间为33msec
2.测试端
vim /etc/resolv.conf
写入:nameserver 172.25.254.117
systemctl restart network
dig www.baidu.com
访问者得到答案的时间为2 msec,明显比第一次访问时,时间缩短了
DNS高速缓存的作用:当访问要请求解析一个域名时,该解析记录就放置在缓存中,后面再有同样的解析请求时,
就直接从缓存中给结果,会减少访问时间。
####DNS正向解析#######
vim /etc/named.conf ###进入文件后删除forwarders {114.114.114.114;};
vim /etc/named.rfc1912.zones
写入:从25行开始写
zone "westos.com" IN {
type master;
file "westos.com.zone";
allow-update{none;};
};
cd /var/named
cp -p named.localhost westos.com.zone
vim /var/named/westos.com.zone
写入:第2行SOA后 两个名字可随便写@ IN SOA dns.westos.com. xbw.westos.com.
第8行:NS dns.westos.com.
第9行:dns A 172.25.254.111
第10行:hello A 172.25.254.222
systemctl restart named
dig dns.westos.com
dig hello.westos.com
vim /etc/named/westos.com.zone
写入:www CNAME node1.westos.com. ###把规则的域名变成不规则的域名
node1 A 172.25.254.110
node1 A 172.25.254.210
dig www.westos.com ##查看解析
#####反向解析#####
systemctl start named
systemctl enable named
systemctl stop firewalld
systemctl disable firewalld
vim /etc/named.rfc1912.zones
写入最后面:zone "254.25.172.in-addr.arpa" IN {
type master;
file "westos.com.ptr";
allow-update {none;};
};
cd /var/named
ls
cp -p named.loopback westos.com.ptr
ls
vim westos.com.ptr
写入:第二行:@ IN SOA dns.westos.com. xbw.westos.com.
第8行:NS dns.westos.com.
第9行:dns A 172.25.254.117
第10行:111 PTR www.westos.com.
第11行:222 PTR hello.westos.com.
systemctl restart named
dig -x 172.25.254.123 ###反向解析
dig -x 172.25.254.234 ###反向解析
#########双向解析##########
cd /var/named
cp -p westos.com.zone westos.com.inter
ls
vim westos.com.inter
修改里面的ip地址
dns A 192.168.1.111
hello A 192.168.1.222
www CNAME node1.westos.com.
node1 A 192.168.1.110
node1 A 192.268.1.210
cp -p /etc/named.rfc1912.zones /etc/named.rfc1912.inter
vim /etc/named.rfc1912.inter
修改 第27行 file "westos.com.inter";
vim /etc/named.conf
写入:先把第52行到58行注释了
在51行写/*,在59行写*/,就是注释的意思
再到后面写入:
view localnet {
match-clients {172.25.254.117;};
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 ###解析网址,查看其ip
2.在另一台主机中
vim /etc/resolv.conf
写入:nameserver 172.25.254.117
dig www.westos.com ##查看解析
两台主机访问同一域名,会得到不同的地址,因为两台主机分别被定义了内网和外网,所以ip不同