How to setup DNS Server in Raspberry Pi| LinuxGist

• Introduction
  • Components of a DNS Server
  • Setting Up Your Own DNS Server on a Raspberry Pi
    • Prerequisites
    • Step-by-Step Guide
    • Testing Your DNS Server
• Conclusion

Introduction

A DNS (Domain Name System) server translates human-readable domain names into IP addresses that computers use to communicate over a network.

Components of a DNS Server

1. Authoritative DNS Servers: These are servers that store the most up-to-date and accurate information about domain name mappings. They respond directly to queries for specific domains.
2. Recursive DNS Servers: These forward requests from client machines to authoritative servers to resolve domain names, then return the results to the client.

Setting Up Your Own DNS Server on a Raspberry Pi

Setting up your own DNS server can be useful for various reasons, such as privacy (using a local DNS resolver), caching frequently accessed domains, or customizing name resolution. Below are the steps to set up a simple recursive DNS server using dnsmasq, which is a lightweight and powerful DNS forwarder.

Prerequisites

• A Raspberry Pi running a Debian-based operating system (e.g., Raspbian).
• An internet connection.

Step-by-Step Guide

1. Update Your System

   sudo apt update && sudo apt upgrade -y
   

2. Install dnsmasq

   sudo apt install dnsmasq
   

3. Configure dnsmasq

   Edit the configuration file /etc/dnsmasq.conf using a text editor like nano.

   sudo nano /etc/dnsmasq.conf
   

   Add or modify the following lines to configure your DNS server:

   # Set this to the IP address of your Raspberry Pi (or any other preferred upstream DNS server)
   server=8.8.8.8
   
   # Optionally, you can add custom domain mappings here
   local=/home.mydomain/
   address=/home.mydomain/192.168.1.100
   
   # Enable recursion to allow the Raspberry Pi to forward queries it doesn't know how to answer
   recursive=yes
   
   # Optionally, enable logging for debugging purposes (uncomment if needed)
   log-queries
   

4. Configure Network Interface

   Edit the network interface configuration file for your Ethernet or Wi-Fi interface. For example, edit /etc/network/interfaces:

   sudo nano /etc/network/interfaces
   

   Add or modify the following lines to set your Raspberry Pi as a DNS server for your local network:

   auto eth0
   iface eth0 inet static
       address 192.168.1.1
       netmask 255.255.255.0
       dns-nameservers 127.0.0.1
   

   This configuration sets your Raspberry Pi’s IP address to 192.168.1.1 and configures it as the DNS server for your local network.

5. Restart dnsmasq

   Apply the changes by restarting the dnsmasq service:

   sudo systemctl restart dnsmasq
   

6. Verify Configuration

   Ensure that dnsmasq is running correctly and listening on the correct port (53):

   sudo netstat -tuln | grep 53
   

   You should see an entry for dnsmasq listening on port 53.

7. Configure DHCP (Optional)

   If you want your Raspberry Pi to act as a DHCP server along with the DNS server, install and configure isc-dhcp-server.

   sudo apt install isc-dhcp-server
   

   Edit the configuration file /etc/dhcp/dhcpd.conf:

   sudo nano /etc/dhcp/dhcpd.conf
   

   Add or modify the following lines to specify your network range and provide the IP address of your Raspberry Pi as the DNS server:

   subnet 192.168.1.0 netmask 255.255.255.0 {
       range 192.168.1.10 192.168.1.100;
       option routers 192.168.1.1;
       option domain-name-servers 192.168.1.1;
   }
   

   Edit the dhcpcd configuration file to use the DHCP server:

   sudo nano /etc/dhcpcd.conf
   

   Add or modify the following line:

   static domain_name_servers=192.168.1.1
   

   Restart isc-dhcp-server and dhcpcd to apply changes:

   sudo systemctl restart isc-dhcp-server
   sudo service dhcpcd restart
   

Testing Your DNS Server

You can test your DNS server by querying it using the nslookup or dig command from another device on your network.

nslookup example.com 192.168.1.1

Or:

dig @192.168.1.1 example.com

Conclusion

You have successfully set up a simple recursive DNS server on your Raspberry Pi. This setup can be useful for caching domain queries, providing custom name resolution, or enhancing the privacy of devices in your local network by using a local resolver instead of querying public DNS servers directly.