Linux

Install Bind9 DNS on Oracle Linux 9

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What is DNS?

DNS stands for Domain Name System. in shorts DNS is a Distributed Database system that is used to associate host names with their respective IP addresses.

Available DNS Software

There are many different implementations of the DNS system today. Each DNS server represents a different implementation of characteristics, such as the interface, platform support, packaging and additional features.

  • BIND
  • PowerDNS
  • Unbound
  • Dnsmasq
  • MaraDNS

Lab Environment

  • DNS Server OS: Oracle linux 9
  • DNS software: Bind9
  • DNS IP Addr: 10.10.2.134/24
  • DNS Network: 10.10.2.0/24
  • Windows Server: 10.10.2.131

Cheat-Sheet

You can find below the steps in-short, for more details skip this part and follow the detailed steps.

#################################
### Set Host and Domain Name
#################################

hostnamectl 
hostnamectl set-hostname dnssrv.lab.com
hostname -s
hostname -d 
hostname -f

#################################
### Set Static IP Addr
#################################

## Oracle Linux 8/7
sudo vim /etc/sysconfig/network-scripts/ifcfg-ens160

# Change this 
BOOTPROTO=none

# Add below
ONBOOT=yes
IPADDR=10.10.2.134
PREFIX=24
GATEWAY=10.10.2.2
DNS1=10.10.2.2
DNS2=10.10.2.134

## Oracle Linux 9
sudo vim /etc/NetworkManager/system-connections/ens160.nmconnection

# add below lines 
[ipv4]
address1=10.10.2.134/24,10.10.2.2
dns=10.10.2.2;10.10.2.134;
method=manual

#################################
### Installation
#################################

sudo dnf install -y bind bind-chroot
rpm -aq | grep bind

#################################
### Configure DNS Server
#################################

su - root
export TIMESTAMP=$(date '+%Y%m%d_%H%M%S')
systemctl stop named
systemctl disable named

# backup the file 
cp -p /etc/named.conf /etc/named.conf.bkp_$TIMESTAMP

vim /etc/named.conf

# Edit below lines
listen-on port 53 { 127.0.0.1; 10.10.2.134; };
allow-query     { localhost; 10.10.2.0/24; };

# validate the named.conf file 
named-checkconf 

#################################
### Create Zones
#################################

# Backup zones file 
su - root
export TIMESTAMP=$(date '+%Y%m%d_%H%M%S')
cp -p /etc/named.rfc1912.zones /etc/named.rfc1912.zones.bkp_$TIMESTAMP  

# Edit the file 
vim /etc/named.rfc1912.zones 

# add below zones to end of the file
//forward zone
zone "lab.com" IN {
     type master;
     file "lab.com.zone";
     allow-update { none; };
     allow-query { any; };
};
//backward zone or reverse zone
zone "2.10.10.in-addr.arpa" IN {
     type master;
     file "2.10.10.in-addr.arpa.zone";
     allow-update { none; };
     allow-query { any; };
};

#################################
### Create Forward Zone file
#################################

cd /var/named
cp -p named.loopback lab.com.zone
# -p to preserve the mode and ownership 

# chown root:named lab.com.zone
vim lab.com.zone
## edit the file to be like below 
$TTL 1D
@       IN SOA  lab.com.         root.lab.com (
                                        0       ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
                IN NS   localhost
localhost       IN A    127.0.0.1
dnssrv          IN A    10.10.2.134



#################################
### Create Backward/Reverse Zone
#################################

cp -p named.localhost 2.10.10.in-addr.arpa.zone
#chown root:named 2.10.10.in-addr.arpa.zone
vim 2.10.10.in-addr.arpa.zone

## Edit the file to be like below 
$TTL 1D
@       IN SOA  lab.com.        root.lab.com. (
                                        0       ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
                IN NS   localhost.
134             IN PTR  dnssrv.lab.com.


#################################
### Validate Configuration
#################################

# check configuration file
named-checkconf
# for chroot named file if activated
mkdir /var/named/chroot/usr/lib64/named
named-checkconf -t /var/named/chroot/ etc/named.conf

# check backward/reverse zone file
named-checkzone 127.0.0.1 /var/named/2.10.10.in-addr.arpa.zone

# check forwared zone file
named-checkzone dnssrv /var/named/lab.com.zone

#################################
### Enable chroot Jail Env
#################################

# check the chroot 
 mount | grep chroot

# Enable chroot 
 /usr/libexec/setup-named-chroot.sh /var/named/chroot on

# check chroot if enabled 
 mount | grep chroot

#################################
### Start named-chroot service
#################################

# Start service
systemctl start named-chroot
systemctl status named-chroot

#################################
### Allow DNS on Firewall
#################################

# check if ports are listening 
ss -anl | grep ":53 "

# add port 53 udp/tcp to firewall
firewall-cmd  --add-port=53/tcp --add-port=53/udp --permanent

# List ports 
firewall-cmd --list-ports

# Apply the changes 
firewall-cmd --reload

# List ports 
firewall-cmd --list-ports

#################################
### Put DNS in Action
#################################

# on DNS server locally add below to resolv.conf
vim /etc/resolv.conf
nameserver 10.10.2.134

# On windows add DNS to network adapter IPv4
10.10.2.134

# show advanced TCP/IP settings append DNS suffix
lab.com 

#################################
### Add DNS Record
#################################

# Open zone file to edit 
vim /var/named/lab.com.zone

# add below record 
win-sqldb01     IN A    10.10.2.131

# Open Reverse zone file to edit 
vim /var/named/2.10.10.in-addr.arpa.zone

# add below record 
win-sqldb01     IN A    10.10.2.131

# restart the server 
systemctl restart named-chroot

# Test from both DNS and Windows Server sides
nslookup win-sqldb01
nslookup 10.10.2.131

#################################
### Stop/Start DNS Service 
#################################

# stop service
systemctl stop named-chroot
systemctl status named-chroot

# disable the chroot jail env
/usr/libexec/setup-named-chroot.sh /var/named/chroot off
mount | grep chroot

##  Start Service 

# enable chroot jail env 
/usr/libexec/setup-named-chroot.sh /var/named/chroot on
mount | grep chroot

# Start service
systemctl start named-chroot
systemctl status named-chroot

Step-1: Customize OS

## Set Proper server name and domain name

# check the hostname configuration
hostnamectl

# set hostname and domain
hostnamectl set-hostname dnssrv.lab.com

## Set Static IP 

#show the available networks
ip a show 

# make sure to make it static like below output
# Oracle linux 7/8
sudo vim /etc/sysconfig/network-scripts/ifcfg-ens160

# Change this 
BOOTPROTO=none

# Add below
ONBOOT=yes
IPADDR=10.10.2.134
PREFIX=24
GATEWAY=10.10.2.2
DNS1=10.10.2.2

# Oracle Linux 9

# edit below file using vim 
sudo vim /etc/NetworkManager/system-connections/ens160.nmconnection

# add below lines 
[ipv4]
address1=10.10.2.134/24,10.10.2.2
dns=10.10.2.2;
method=manual

Step-2: Install Bind Utilities

Install the bind package.

sudo dnf install -y bind bind-chroot
rpm -aq | grep bind

Important files and directories good to know about, before we get stated:

# main configuration File 
/etc/named.conf 

# An auxiliary Direcotry for configuration file that are included in the man configuration file
/etc/named/

# File contains the Forward and Reverse Zones file names and configurations
/etc/named.rfc1912.zones

# conatins the zones files 
/var/named/

# Contains the jailed environment for bind DNS
/var/named/chroot/

Step-3: Configure DNS Server (named.conf)

This file holds the bind configuration, which affect the service

export TIMESTAMP=$(date '+%Y%m%d_%H%M%S')
systemctl stop named
systemctl disable named

# backup the file 
cp -p /etc/named.conf /etc/named.conf.bkp_$TIMESTAMP

vim /etc/named.conf

# Edit below lines
listen-on port 53 { 127.0.0.1; 10.10.2.134; };
allow-query     { localhost; 10.10.2.0/24; };

# validate the named.conf file 
named-checkconf

Step-4: Create Zones

Next create the DNS zone entries in the file /etc/named.rfc1912.zones.This is where you will configure the forward and reverse zones.

You can add the zones in named.conf file in sake of keeping everything organized better to place them in named.rfc1912.zones file.

# Backup zones file
su - root
export TIMESTAMP=$(date '+%Y%m%d_%H%M%S')
cp -p /etc/named.rfc1912.zones /etc/named.rfc1912.zones.bkp_$TIMESTAMP  

# Edit the file 
vim /etc/named.rfc1912.zones 

# add below zones to end of the file
//forward zone
zone "lab.com" IN {
     type master;
     file "lab.com.zone";
     allow-update { none; };
     allow-query { any; };
};
//backward zone or reverse zone
zone "2.10.10.in-addr.arpa" IN {
     type master;
     file "2.10.10.in-addr.arpa.zone";
     allow-update { none; };
     allow-query { any; };
};

Step-5: Configure Forward Zone


cd /var/named
cp -p named.loopback lab.com.zone
# -p to preserve the mode and ownership 

# chown root:named lab.com.zone
vim lab.com.zone
## edit the file to be like below 
$TTL 1D
@       IN SOA  lab.com.         root.lab.com (
                                        0       ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
                IN NS   localhost
localhost       IN A    127.0.0.1
dnssrv          IN A    10.10.2.134

Step-6: Configure Reverse Zone

cp -p named.localhost 2.10.10.in-addr.arpa.zone
vim 2.10.10.in-addr.arpa.zone

## Edit the file to be like below 
$TTL 1D
@       IN SOA  lab.com.        root.lab.com. (
                                        0       ; serial
                                        1D      ; refresh
                                        1H      ; retry
                                        1W      ; expire
                                        3H )    ; minimum
                IN NS   localhost.
134             IN PTR  dnssrv.lab.com.

Step-7: Validate Configurations

# check configuration file
named-checkconf
# for chroot named file
mkdir /var/named/chroot/usr/lib64/named
named-checkconf -t /var/named/chroot/ etc/named.conf

# check backward/reverse zone file
named-checkzone 127.0.0.1 /var/named/2.10.10.in-addr.arpa.zone

# check forwared zone file
named-checkzone dnssrv /var/named/lab.com.zone

Step-8: Enable Chroot Environment

# check the chroot 
mount | grep chroot

# Enable chroot 
/usr/libexec/setup-named-chroot.sh /var/named/chroot on

# check chroot if enabled 
mount | grep chroot

# start named-chroot service
systemctl start named-chroot
systemctl status named-chroot

Step-9: Allow DNS on Firewall

# check if ports are listening 
ss -anl | grep ":53 "

# add port 53 udp/tcp to firewall
firewall-cmd --add-port=53/udp --permanent

# List ports 
firewall-cmd --list-ports

# Apply the changes 
firewall-cmd --reload

# List ports 
firewall-cmd --list-ports

Step-10: Put DNS in action

# on DNS server locally add below to resolv.conf
vim /etc/resolv.conf
nameserver 10.10.2.134

# On windows add DNS to network adapter IPv4
10.10.2.134

# show advanced TCP/IP settings append DNS suffix
lab.com

Step-11: Add A Record

# Open zone file to edit 
vim /var/named/lab.com.zone

# add below record 
win-sqldb01     IN A    10.10.2.131

# Open Reverse zone file to edit 
vim /var/named/2.10.10.in-addr.arpa.zone

# add below record 
win-sqldb01     IN A    10.10.2.131

# restart the server 
systemctl restart named-chroot

# Test from both DNS and Windows Server sides
nslookup win-sqldb01
nslookup 10.10.2.131

Step-12: Start/Stop DNS

## Stop Service

# stop service
systemctl stop named-chroot
systemctl status named-chroot

# disable the chroot jail env
/usr/libexec/setup-named-chroot.sh /var/named/chroot off
mount | grep chroot

##  Start Service 

# enable chroot jail env 
/usr/libexec/setup-named-chroot.sh /var/named/chroot on
mount | grep chroot

# Start service
systemctl start named-chroot
systemctl status named-chroot

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