centOS7下DNS服务器的安装与配置

DNS  即Domain Name System（域名系统）的缩写，它是一种将ip地址转换成对应的主机名或将主机名转换成与之相对应ip地址的一种机制。其中通过域名解析出ip地址的叫做正向解析，通过ip地址解析出域名的叫做反向解析。

一、安装BIND服务器软件并启动 

1. yum源安装bind

[root@dns ~]# yum -y install bind*

在安装完BIND后，系统会多一个用户named。

2.启动DNS服务

[root@dns ~]# systemctl start named.service

3.查看named进程是否正常启动：

[root@dns ~]# ps -ef|grep named
named 19872 1 0 02:37 ? 00:00:00 /usr/sbin/named -u named -c /etc/named.conf
root 19877 19619 0 02:38 pts/1 00:00:00 grep --color=auto named

4.DNS采用的UDP协议，监听53号端口，进一步检验named工作是否正常：

[root@dns ~]# netstat -an|grep :53
tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN
tcp6 0 0 ::1:53 :::* LISTEN
udp 0 0 127.0.0.1:53 0.0.0.0:*
udp6 0 0 ::1:53 :::*

5.防火墙开放TCP和UDP的53号端口：

[root@dns ~]# iptables -I INPUT -p tcp --dport 53 -j ACCEPT

[root@dns ~]# iptables -I INPUT -p udp --dport 53 -j ACCEPT

二、DNS服务的相关配置文件

对于BIND，需要配置的主要文件为/etc/named.conf。另外两个文件，/etc/named.isc-dlv.key保存加密用的可以，/etc/named.rfc1912.zones扩展配置文件

1.修改主配置文件/etc/named.conf

要注意在修改之前要先进行备份，使用

[root@dns ~]# cp -p /etc/named.conf /etc/named.conf.bak

命令备份，参数-p表示备份文件与源文件的属性一致。

修改文件：

[root@dns ~]# vim /etc/named.conf

================================================================

options {
listen-on port 53 { any; };
listen-on-v6 port 53 { node; };
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";
memstatistics-file "/var/named/data/named_mem_stats.txt";
recursing-file "/var/named/data/named.recursing";
secroots-file "/var/named/data/named.secroots";
allow-query { any; };
recursion yes;
dnssec-enable no;
dnssec-validation no;
bindkeys-file "/etc/named.root.key";
managed-keys-directory "/var/named/dynamic";
pid-file "/run/named/named.pid";
session-keyfile "/run/named/session.key";
};
logging {
channel default_debug {
file "data/named.run";
severity dynamic;
};
};
zone "." IN {
type hint;
file "named.ca";
};

zone "ruolan.com" IN {
type master;
file "ruolan.com.zone";
allow-update { none; };
};

zone "1.168.192.in-addr.arpa" IN {
type master;
file "1.168.192.in-addr.arpa.zone";
allow-update { none; };
};

#include "/etc/named.rfc1912.zones";
#include "/etc/named.root.key";

================================================================

2.修改/etc/named.rfc1912.zones

添加正向解析域  ruolan.com,逆向解析域          其对应的域解析文件分别为由file指定的

暂无

3.添加/var/named/ruolan.com,zone  

可以将模板文件复制一份，在进行修改,使用命令

[root@dns ~]# cp /var/named/named.localhost /var/named/ruolan.com.zone

进入ruolan.com.zone进行配置

[root@dns ~]# vim /var/named/ruolan.com.zone

==============================================

$TTL 1D
@ IN SOA @ dns1.ruolan.com. (
2019092301 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
NS @
A 127.0.0.1
AAAA ::1
ftp IN A 192.168.1.248

www IN A 192.168.1.248

abc IN A 192.168.1.249

==============================================

4.添加/var/named/

[root@dns ~]# vim /var/named/1.168.192.in-addr.arpa.zone

========================================================

$TTL 1D
@ IN SOA @ 248.1.168.192.in-addr.arpa. (
2019092301 ; serial
1D ; refreah
1H ; retry
1W ; expire
3H ) ; minimum
NS @
A 192.168.1.248
AAAA ::1
PTR ftp.ruolan.com

248 PTR www.ruolan.com

249 PTR abc.ruolan.com

========================================================

5.配置区域文件的权限

[root@dns ~]# chown named.named -R /var/named/*.zone

6.重启服务

[root@dns ~]# systemctl restart named

三、在Linux下的DNS客户端的设置及测试

配置/etc/resolv.conf文件。

[root@dns ~]# vim /etc/resolv.conf

================================

nameserver 192.168.1.248

================================

BIND软件包本身提供了测试工具nslookup

3.1反向测试

[root@dns ~]# nslookup
> 192.168.1.248
248.1.168.192.in-addr.arpa name = www.ruolan.com.1.168.192.in-addr.arpa.
> 192.168.1.249
249.1.168.192.in-addr.arpa name = abc.ruolan.com.1.168.192.in-addr.arpa.

3.2正向测试

> ftp.ruolan.com
Server: 192.168.1.248
Address: 192.168.1.248#53

Name: ftp.ruolan.com
Address: 192.168.1.248
> www.ruolan.com
Server: 192.168.1.248
Address: 192.168.1.248#53

Name: www.ruolan.com
Address: 192.168.1.248
> abc.ruolan.com
Server: 192.168.1.248
Address: 192.168.1.248#53

Name: abc.ruolan.com
Address: 192.168.1.249

Ok，配置成功