DNS Configuration on RHEL7/ Cent OS 7

                 Domain Naming System is a naming convention for computers, which is connected to the internet. Its not possible to remember all the web server IP Address. So, here its comes as a resolution for this. Because, It will translate from the IP Address to Name and Name to IP Address.

We are going to see how to setup DNS in RHEL 7 and Cent OS 7.

Requirement:

Host Name: server.linuxbookcenter.com
IP Address: 192.168.43.226

Packages:
1. bind
2. bind-utils

Installing bind packages:

[root@server]# yum -y install bind*

BIND Configuring:

We are going to configure the “/etc/named.conf” file for BIND configuration.
open the file using vi editor and comment out two lines like shown below. This lines allow your DNS to listen all the IP Address.

Add your network by modifying “allow-query” line in the named.conf file to all the computers to do name transition which connected in this network

#vi /etc/named.conf

[root@server ~]# vi /etc/named.conf 

options {
 #listen-on port 53 { 127.0.0.1; };
 #listen-on-v6 port 53 { ::1; };

 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";

 allow-query { localhost; 192.168.43.226/24;}; 

And the zone file information will be available in “/etc/named/rfc1912.zones” file by default. Here we should modify the entry based on our requirement.

Note: This entry contains the forward and reverse zone file names.

This file location included in “/etc/named.conf” file. Find the below screenshot.

Now save and exit from the “/etc/named.conf” file.

Provide zone file information entry:

edit the “/etc/named.rfc1912.zones”  file to provide the zone file information entries.

[root@server ~]# vi /etc/named.rfc1912.zones

And make the below entries or modify the existing one based on our requirement.

zone "localhost.localdomain" IN {
 type master;
 file "named.localhost";
 allow-update { none; };
};

zone "lbcdomain.com" IN {
 type master;
 file "fwd.lbcdomain.com.db";
 allow-update { none; };
};

zone "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa" IN {
 type master;
 file "named.loopback";
 allow-update { none; };
};

zone "1.0.0.127.in-addr.arpa" IN {
 type master;
 file "named.loopback";
 allow-update { none; };
};

zone "226.43.168.192.in-addr.arpa" IN {
 type master;
 file "43.168.192.db";
 allow-update { none; };
};

Create and Configure the Zone files:

Default location for the zone file’s :  /var/named

create a forward zone file with “fwd.lbcdomain.com.db”   name.

[root@server named]# vi /var/named/fwd.lbcdomain.com.db

$TTL 86400
@ IN SOA server.lbcdomain.com. root.lbcdomain.com. (
                            20171129 ; serial
                            3600     ; refresh
                            1800 ; retry
                            604800 ; expire
                            86400 ) ; minimum
;Name server info
@ IN NS server.lbcdomain.com.

;Name server Ip info
server IN A 192.168.43.226

;Mail exchanger
lbcdomain.com. IN MX 10 mail.lbcdomain.com.

;A - Record Hostname to IP Address
www IN A 192.168.43.10
mail IN A 192.168.43.15

;CNAME Record
ftp IN CNAME www.lbcdomain.com.

Save and exit from the file and create reverse zone file with the name of “43.168.192.db”

PTR – Pointer

SOA – Start of Authority

[root@server ~]# vi /var/named/43.168.192.db

$TTL 86400
@ IN SOA server.lbcdomain.com. root.lbcdomain.com. (
                        20171129 ; serial
                        3600 ; refresh
                        1800 ; retry
                        604800 ; expire
                        86400 ) ; minimum

;Name server info
@ IN NS server.lbcdomain.com.

;Reverse lookup info
226 IN PTR server.lbcdomain.com.

;PTR Record for IP to Hostname
10 IN PTR www.lbcdomain.com.
15 IN PTR mail.lbcdomain.com.

We completed all the configuration and we should restart the bind service.

[root@server ~]# systemctl restart named

Make it enabled in system startup.

[root@server ~]# systemctl enable named

Output: