实现DNS的反向解析

反向区域

区域名称：网络地址反写.in-addr.arpa.

172.16.100. --> 100.16.172.in-addr.arpa.

1. 定义区域

   zone "ZONE_NAME" IN {
   type {master|slave|forward}；
   file "网络地址.zone"
   };
   

2. 定义区域解析库文件

   注意：不需要MX,以PTR记录为主

反向区域示例

$TTL 86400
$ORIGIN 10.0.0.11.in-addr.arpa.
@ IN SOA ns1.abcd.com. admin.abcd.com. (
			123456
			1H
			5M
			7D
			1D )
IN NS ns1.abcd.com.
IN NS ns2.abcd.com.
11 IN PTR ns1.abcd.com.
11 IN PTR www.abcd.com.
12 IN PTR mx1.abcd.com.
12 IN PTR www.abcd.com.
13 IN PTR mx2.abcd.com.

设置反向解析域

$ vim /etc/named.rfc1912.zones

zone "3.168.192.in-addr.arpa" IN {
        type master;
        file "192.168.3.zone";
};

新建区域数据库文件

$ touch /var/named/192.168.3.zone
$ chgrp named /var/named/192.168.3.zone   #修改所属组
$ chmod o= /var/named/192.168.3.zone		#去掉other的权限
$ vim /var/named/192.168.3.zone			#编写数据库文件

$TTL 1D
@   IN  SOA  master admin ( 50 2H 10M 1W 1D )
        NS   master
master  A   192.168.3.102
101     PTR www.hxg101.com.
102     PTR www.hxg102.org. 

重新加载数据

$ rndc reload

客户端测试

$ dig -x 192.168.3.101
#或者
$ dig -t PTR 101.3.168.192.in-addr.arpa.

; <<>> DiG 9.11.4-P2-RedHat-9.11.4-16.P2.el7 <<>> -x 192.168.3.101
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 33160
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;101.3.168.192.in-addr.arpa.	IN	PTR

;; ANSWER SECTION:
101.3.168.192.in-addr.arpa. 86400 IN	PTR	www.hxg101.com.

;; AUTHORITY SECTION:
3.168.192.in-addr.arpa.	86400	IN	NS	master.3.168.192.in-addr.arpa.

;; ADDITIONAL SECTION:
master.3.168.192.in-addr.arpa. 86400 IN	A	192.168.3.102

;; Query time: 0 msec
;; SERVER: 192.168.3.102#53(192.168.3.102)
;; WHEN: 一 6月 08 07:14:16 CST 2020
;; MSG SIZE  rcvd: 120