Objective

Configure a Secondary DNS server that automatically replicates DNS zones from the Primary DNS server using zone transfers (AXFR).

Environment

  • Virtualization: VirtualBox
  • OS: ( 1 Primary DNS Server VM + 1 Secondary DNS Server + 1 Web Server VM + 1 Client VM)

Network Topology

dns-tolopogy

Prerequisites

This lab builds upon the following previous labs:

  • Private DNS Infrastructure with BIND9
  • Hosting Multiple Websites on One Server Using Nginx

The following components are assumed to already be configured:

  • BIND9 is installed and running on the DNS server.
  • The forward lookup zone company.lab has already been created.
  • The forward zone file (/etc/bind/db.company.lab) contains the required DNS records.
  • The client is configured to use the internal DNS server (192.168.10.10).
  • DNS resolution between all virtual machines has been verified.
  • The web server hosts multiple virtual websites using Nginx.

This lab extends the existing DNS infrastructure by adding a reverse lookup zone.

Phase 1 - Prepare the Second DNS Server

Step 1 - Install BIND9

sudo apt update
sudo apt install bind9 bind9-utils dnsutils
sudo systemctl status bind9

sec-dns

Step 2 - Verify connectivity

ping 192.168.10.10

ping

Step 3 - Check the Port 53 is Listening

ss -tulnp | grep :53

port

Phase 2 - Configure the Primary DNS Server

Step 1 - Modify the zone file on primary dns server

sudo nano /etc/bind/named.conf.local

primary

Step 2 - Verify the Configuration

sudo named-checkconf
sudo systemctl reload bind9

Phase 3 - Configure the Secondary DNS Server

Step 1 - Modify the zone file on secondary dns server

sudo nano /etc/bind/named.conf.local

secondary

Step 2 - Verify the Configuration

sudo named-checkconf
sudo systemctl restart bind9

Step 3 - Verify the Zone Files

ls -l /var/cache/bind/

secondary-files