How to Configure DNS Server in Linux Ubuntu?

In the vast realm of Linux administration, understanding how to configure a DNS (Domain Name System) server is a fundamental skill. The DNS server plays a pivotal role in translating human-readable domain names into IP addresses, facilitating seamless communication on the internet. This article serves as a comprehensive guide on configuring a DNS server in Linux Ubuntu, offering step-by-step instructions and practical examples to empower both beginners and experienced users alike.

Prerequisites:

Before diving into the configuration process, ensure that you have root or sudo access to your Ubuntu system. Additionally, have a basic understanding of the terminal commands used in this guide.

Step 1: Install BIND (Berkeley Internet Name Domain) on Ubuntu:

BIND is a widely used DNS server software. Install it using the following command:

sudo apt update
sudo apt install bind9

Step 2: Configure BIND DNS Server:

Navigate to the BIND configuration directory:

cd /etc/bind

Open the main configuration file named named.conf.options with a text editor of your choice (e.g., nano or vim):

sudo nano named.conf.options

Within this file, configure the DNS server options. Ensure that the 'forwarders' section contains valid DNS server IP addresses. Save and exit.

Step 3: Create DNS Zone Files:

Navigate to the 'zones' directory:

cd /etc/bind/zones

Create a forward zone file (e.g., example.com) for your domain:

sudo nano db.example.com

Add essential DNS records, including SOA, NS, A, and MX records. Save and exit.

Step 4: Configure Reverse DNS Zone:

Create a reverse zone file (e.g., 1.168.192.in-addr.arpa):

sudo nano db.192

Define PTR (Pointer) records for reverse DNS mapping. Save and exit.

Step 5: Update Named Configuration File:

Modify the main named configuration file to include the newly created zone files:

sudo nano named.conf.local

Add references to your forward and reverse zone files. Save and exit.

Step 6: Restart BIND Service:

Restart the BIND service to apply the changes:

sudo service bind9 restart

Step 7: Test DNS Configuration:

Verify the DNS server's functionality using the dig command. For example:

dig example.com

Ensure that the response includes the correct IP address.

Additional Tips and Examples:

• Securing BIND: Implement security measures like ACLs (Access Control Lists) to restrict access to your DNS server.
• Logging: Enable logging in BIND configuration to monitor server activities and troubleshoot issues effectively.