How to Install dnsmasq DNS Server on Raspberry Pi OS

Setting up a Domain Name System (DNS) server on your Raspberry Pi running Raspberry Pi OS Debian 12 Bookworm can significantly enhance your network’s efficiency by reducing lookup times and improving overall connectivity. This comprehensive guide will walk you through the process of installing and configuring dnsmasq, a lightweight DNS forwarder ideal for small-scale networks.

Prequisites

Before we begin, ensure you have the following:

• Raspberry Pi: Model 2, 3, or 4.
• Operating System: Raspberry Pi OS Debian 12 Bookworm.
• Network Connection: A stable internet connection via Ethernet or Wi-Fi.
• Static IP Address: It’s recommended to assign a static IP to your Raspberry Pi to ensure consistent network identification.

Step 1: Update Your System

Start by updating your package lists and upgrading existing packages to their latest versions. Open a terminal and execute:

sudo apt update
sudo apt upgrade -y

This ensures that your system has the latest security patches and software updates.

Step 2: Install dnsmasq

dnsmasq is a lightweight DNS forwarder and DHCP server designed for small networks. Install it using:

sudo apt install dnsmasq -y

Step 3: Configure dnsmasq

After installation, you’ll need to configure dnsmasq to function as your DNS server. Follow these steps:

1. Backup the Original Configuration: It’s good practice to keep a backup of the original configuration file.

   sudo cp /etc/dnsmasq.conf /etc/dnsmasq.conf.backup
   

2. Edit the Configuration File: Open the dnsmasq configuration file in a text editor:

   sudo nano /etc/dnsmasq.conf
   

3. Modify the Following Settings:

   • Prevent Forwarding of Plain Names: Uncomment the domain-needed line to avoid forwarding incomplete domain names.

     domain-needed
     

   • Block Private IP Reverse Lookups: Uncomment the bogus-priv line to block reverse lookups for private IP ranges.

     bogus-priv
     

   • Specify Upstream DNS Servers: Add your preferred upstream DNS servers. For example, to use Google’s DNS servers:

     server=8.8.8.8
     server=8.8.4.4
     

   • Set Cache Size: Increase the cache size to improve performance.

     cache-size=1000
     

4. Save and Exit: After making the changes, save the file by pressing CTRL + X, then Y, and press Enter.

Step 4: Restart and Enable dnsmasq

To apply the changes, restart the dnsmasq service:

sudo systemctl restart dnsmasq

Enable dnsmasq to start on boot:

sudo systemctl enable dnsmasq

Step 5: Configure Network Manager for a Static IP

With the release of Raspberry Pi OS Bookworm, networking is managed by NetworkManager. To assign a static IP address:

1. List Network Interfaces: Identify your network connection name.

   nmcli connection show
   

   Look for the interface, typically named Wired connection 1 for Ethernet or your Wi-Fi SSID.

2. Set Static IP Address: Replace CONNECTION_NAME with your actual connection name.

   sudo nmcli connection modify "CONNECTION_NAME" ipv4.addresses 192.168.1.100/24 ipv4.method manual
   

3. Set Gateway and DNS: Assuming your router’s IP is 192.168.1.1:

   sudo nmcli connection modify "CONNECTION_NAME" ipv4.gateway 192.168.1.1
   sudo nmcli connection modify "CONNECTION_NAME" ipv4.dns "192.168.1.1,8.8.8.8"
   

4. Apply Changes: Bring the connection down and up to apply changes.

   sudo nmcli connection down "CONNECTION_NAME" && sudo nmcli connection up "CONNECTION_NAME"
   

Step 6: Test the DNS Server

To verify that your Raspberry Pi is correctly resolving DNS queries:

1. Install dnsutils: If not already installed, to use the dig command.

   sudo apt install dnsutils -y
   

2. Perform a Test Query: Use the dig command to test DNS resolution.

   dig example.com @localhost
   

Check the output for a valid response and note the query time. Subsequent queries should be faster due to caching.

Step 7: Configure Client Devices

To utilize your Raspberry Pi as the DNS server, configure other devices on your network to use its static IP address as their primary DNS server. This setting is typically found in the network configuration section of each device.

Conclusion

By following this guide, you’ve successfully transformed your Raspberry Pi running Debian 12 Bookworm into a lightweight and efficient DNS server using dnsmasq. This setup allows your network to benefit from faster domain lookups, a reduced dependency on external DNS servers, and improved overall network performance.

Key benefits of this configuration include:

• Local Caching: Frequently accessed domains are cached, speeding up subsequent requests.
• Customizability: You can add custom DNS records or override specific domain names for your local network.
• Reduced Bandwidth: Cached responses reduce the need for repeated queries to external DNS servers.

To further enhance your setup, consider the following:

1. Monitoring Logs: Check /var/log/syslog for dnsmasq logs to monitor DNS queries and ensure everything is running smoothly.
2. Security Enhancements: Implement firewall rules using ufw or iptables to restrict access to the DNS server to devices within your local network.
3. Advanced DNS Features: Explore additional dnsmasq options, such as DHCP integration or filtering specific domains.

With this DNS server in place, your Raspberry Pi not only becomes a central hub for managing network queries but also a powerful tool for improving your network’s efficiency. Whether for personal use or small-scale enterprise projects, this setup ensures a robust and reliable DNS service. Happy networking!