This document provides instructions for configuring a DNS server on a Linux system. It involves setting a static IP address and hostname, installing bind packages, configuring the named.conf and zone files, and testing the DNS resolution. Key steps include editing configuration files like ifcfg, hosts, named.conf, and zone files; installing and enabling the named service; and checking DNS resolution works for internal and external names.

1. Application: Name Resulation
Name => IP (www.dbl-group.com => 203.112.194.17)
IP => Name (203.112.194.17 => www.dbl-group.com)
Daemon: named
Packages: bind
Port: 53
Protocol: TCP and UdP
Configuration file:
=> /etc/sysconfig/network-scripts/ifcfg-en*
=> /etc/hosts
=> /etc/hostname
=> /etc/named.conf
=> /etc/named.rfc1912.zones
=> /var/named/named.localhost (Forward Zone)
=> /var/named/named.looback (Reverse Zone)
Step 01: Set Static IP Address and DNS:
--------------------------------------
[root@desktopX ~]# cd /etc/sysconfig/network-scripts/
[root@desktopX network-scripts]# ls
[root@desktopX network-scripts]# vim ifcfg-en* ; your Interface name
NAME=********
HWADDR=*******
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.11.X
NETMASK=255.255.255.0
GATEWAY=192.168.11.1
ONBOOT=yes
DNS1=192.168.11.X
[root@desktopX network-scripts]# systemctl stop NetworkManager.service
[root@desktopX network-scripts]# systemctl disable NetworkManager.service
[root@desktopX network-scripts]# systemctl restart network.service
[root@desktopX network-scripts]# cat /etc/resolv.conf
Step 02: Local resolver entry:
------------------------------
[root@desktopX ~]# vim /etc/hosts
192.168.11.X ns1.dbl-group.com ns1 ; add below of 2 lines
* save and exit
[root@desktopX ~]# ping ns1.dbl-group.com

2. Step 03: Set Static Host Name and Reboot:
----------------------------------------
[root@desktopX ~]# vim /etc/hostname
ns1.dbl-group.com
[root@desktopX ~]# reboot
Step 04: Install Required RPM:
------------------------------
[root@ns1 ~]# yum install bind* -y
Step 05: Allow DNS Server IP and Network:
----------------------------------------
[root@ns1 ~]# cp /etc/named.conf /etc/named.conf.backup
[root@ns1 ~]# vim /etc/named.conf
11 listen-on port 53 { 127.0.0.1; 192.168.11.X; };
12 # listen-on-v6 port 53 { ::1; };
17 allow-query { localhost; 192.168.11.0/24; };
Step 06: Set Forward and Reverse Zones:
---------------------------------------
[root@ns1 ~]# cp /etc/named.rfc1912.zones /etc/named.rfc1912.zones.backup
[root@ns1 ~]# vim /etc/named.rfc1912.zones
19 zone "dbl-group.com" IN {
20 type master;
21 file "dbl-group.com.for";
22 allow-update { none; };
23 };
31 zone "11.168.192.in-addr.arpa" IN {
32 type master;
33 file "dbl-group.com.rev";
34 allow-update { none; };
35 };
Step 07: Create Forward and Reverse Zone Files:
-----------------------------------------------
[root@ns1 Desktop]# cd /var/named/
[root@ns1 named]# ls
[root@ns1 named]# cp named.localhost dbl-group.com.for
[root@ns1 named]# cp named.loopback dbl-group.com.rev
[root@ns1 named]# ls -l
Step 08: Set Ownership to Forward and Reverse Zone Files:
---------------------------------------------------------
[root@ns1 named]# ll example.com.*
-rw-r-----. 1 root root 152 Mar 21 13:59 dbl-group.com.for
-rw-r-----. 1 root root 168 Mar 21 13:59 dbl-group.com.rev
[root@ns1 named]# chgrp named dbl-group.com.*

3. [root@ns1 named]# ll dbl-group.com.*
-rw-r-----. 1 root named 152 Mar 21 13:59 dbl-group.com.for
-rw-r-----. 1 root named 168 Mar 21 13:59 dbl-group.com.rev
Step 09: Edit Forward Zone File:
--------------------------------
[root@ns1 named]# vim dbl-group.com.for
$TTL 1D
@ IN SOA ns1.dbl-group.com. root.example.com. (
0 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
IN NS ns1.dbl-group.com.
IN A 192.168.11.X
ns1 IN A 192.168.11.X
Note:
-----
SOA - Start of Authority
IN - Internet
NS - Name Server (DNS Server)
A - Host Record (IP Address)
root - email admin
PTR - Pointer (Reverse)
Step 10: Edit Reverse Zone File:
--------------------------------
[root@ns1 named]# vim dbl-group.com.rev
$TTL 1D
@ IN SOA ns1.dbl-group.com. root.dbl-group.com. (
0 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
IN NS ns1.dbl-group.com.
X IN PTR ns1.dbl-group.com.
Step 11: Service restart and configured active at boot time:
------------------------------------------------------------
[root@ns1 named]# systemctl restart named.service
[root@ns1 named]# systemctl enable named.service
Step 12: Checking DNS

4. ---------------------
[root@ns1 named]# nslookup ns1.dbl-group.com
Server: 192.168.11.X
Address: 192.168.11.X#53
Name: ns1.dbl-group.com
Address: 192.168.11.X
[root@ns1 named]# dig -x 192.168.11.X ; here -X is option
status: NOERROR
[root@ns1 named]# dig ns1.dbl-group.com
status: NOERROR
[root@ns1 named]# ping www.google.com
======================= Thank you ======================