Linux下DNS服务器配置
　　简要描述各种DNS服务器的配置方法。包括正向解析DNS服务器、逆向解析DNS服务器、主从DNS服务器。
　　实验环境整体配置
　　关闭SElinux
　　setenfore 0
　　清空防火墙
　　iptables -F
　　修改主配置文件 /etc/named.conf
#监听本机外网端口
listen-on port 53 { 127.0.0.1;192.168.45.202; };
#不监听ipv6
//listen-on-v6 port 53 { ::1; };
#允许查询
allow-query     { any; };
#关闭dnssec
dnssec-enable no;
dnssec-validation no;
　　配置正向解析DNS服务器配置
　　修改zone配置 /etc/named.rfc1912.zones
#增加zone文件
zone "easylinux.com" IN {
type master;
file "easylinux.com.zone";
allow-update { none;  };
};
　　添加easylinux.com.zone文件至 /var/named
$TTL 86400
$ORIGIN easylinux.com.
@       IN      SOA     easylinux.com.  nsadmin.easylinux.com. (
20170528
2H
1M
1W
1D
)
IN      NS      ns1.easylinux.com.
IN      NS      ns2.easylinux.com.
IN      MX      10      mx.easylinux.com.
ns1     IN      A       192.168.45.100
ns2     IN      A       192.168.45.101
mx      IN      A       192.168.45.102
www     IN      A       192.168.45.201
web     IN      CNAME   www
　　验证解析
~]# dig easylinux.com. @192.168.45.202
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6 <<>> easylinux.com. @192.168.45.202
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY， status: NOERROR， id: 48423
;; flags: qr aa rd ra; QUERY: 1， ANSWER: 0， AUTHORITY: 1， ADDITIONAL: 0
;; QUESTION SECTION:
;easylinux.com.            IN    A
;; AUTHORITY SECTION:
easylinux.com.        86400    IN    SOA    easylinux.com. nsadmin.easylinux.com. 20170528 7200 60 604800 86400
;; Query time: 0 msec
;; SERVER: 192.168.45.202#53(192.168.45.202)
;; WHEN: Mon May 22 11:49:28 2017
;; MSG SIZE  rcvd: 75
[root@CentOS68every named]# host easylinux.com. @192.168.45.202
host: couldn't get address for '@192.168.45.202': failure
[root@CentOS68every named]# host easylinux.com. 192.168.45.202
Using domain server:
Name: 192.168.45.202
Address: 192.168.45.202#53
Aliases:
easylinux.com mail is handled by 10 mx.easylinux.com.
　　配置逆向解析DNS
　　修改zone配置 /etc/named.rfc1912.zones
zone "45.168.192.in-addr.arpa" IN {
type master;
file "192.168.45.zone";
allow-update { none;  };
};
添加192.168.45.zone文件至 /var/named
$TTL 86400
$ORIGIN 45.168.192.in-addr.arpa.
@       IN      SOA     ns1.easylinux.com.      nsadmin.easylinux.com. (
20170528
2H
1M
1W
1D
)
IN      NS      ns1.easylinux.com.
IN      NS      ns2.easylinux.com.
192.168.45.100  IN      PTR     ns1.easylinux.com.
192.168.45.101  IN      PTR     ns2.easylinux.com.
192.168.45.102  IN      PTR     mx.easylinux.com.
192.168.45.201  IN      PTR     www.easylinux.com.
　　验证解析
~]# dig -x 192.168.45.201 @192.168.45.202
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.47.rc1.el6 <<>> -x 192.168.45.201 @192.168.45.202
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY， status: NOERROR， id: 22989
;; flags: qr aa rd ra; QUERY: 1， ANSWER: 0， AUTHORITY: 1， ADDITIONAL: 0
;; QUESTION SECTION:
;201.45.168.192.in-addr.arpa.    IN    PTR
;; AUTHORITY SECTION:
45.168.192.in-addr.arpa. 86400    IN    SOA    ns1.easylinux.com. nsadmin.easylinux.com. 20170528 7200 60 604800 86400
;; Query time: 1 msec
;; SERVER: 192.168.45.202#53(192.168.45.202)
;; WHEN: Mon May 22 12:06:51 2017
;; MSG SIZE  rcvd: 106
　　配置主从服务器
　　配置解析easylinux.com.的从服务器
　　增加一个从zone配置 /etc/named.rfc1912.zones
zone "easylinux.com" IN {
type slave;
file "slaves/easylinux.com.zone";
masters { 192.168.45.202; };
};
　　查看是否自动生成zone文件
　　~]# ls /var/named/slaves/
　　easylinux.com.zone
　　验证配置
~]# dig www.easylinux.com @192.168.45.203
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6 <<>> www.easylinux.com @192.168.45.203
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY， status: NOERROR， id: 28361
;; flags: qr aa rd ra; QUERY: 1， ANSWER: 1， AUTHORITY: 2， ADDITIONAL: 2
;; QUESTION SECTION:
;www.easylinux.com.        IN    A
;; ANSWER SECTION:
www.easylinux.com.    86400    IN    A    192.168.45.201
;; AUTHORITY SECTION:
easylinux.com.        86400    IN    NS    ns2.easylinux.com.
easylinux.com.        86400    IN    NS    ns1.easylinux.com.
;; ADDITIONAL SECTION:
ns1.easylinux.com.    86400    IN    A    192.168.45.100
ns2.easylinux.com.    86400    IN    A    192.168.45.101
;; Query time: 1 msec
;; SERVER: 192.168.45.203#53(192.168.45.203)
;; WHEN: Fri May 26 18:01:36 2017
;; MSG SIZE  rcvd: 119