Securing Your Ubuntu 22.04 Network: A Comprehensive Guide to DNS over HTTPS (DoH)

DNS over HTTPS (DoH) is a method of encrypting your DNS queries, enhancing your online privacy and security. In this comprehensive guide, we'll explore how to configure DoH on your Ubuntu 22.04 system, covering various methods and troubleshooting common issues. By encrypting your DNS traffic, you prevent your Internet Service Provider (ISP) and potential eavesdroppers from seeing which websites you visit.

Understanding the Benefits of DNS over HTTPS

Traditional DNS queries are sent in plain text, making them vulnerable to interception and manipulation. DoH mitigates this risk by encapsulating DNS queries within HTTPS requests, leveraging the security features of TLS encryption. The key benefits include:

• Enhanced Privacy: Your DNS queries are hidden from your ISP and other potential network observers.
• Improved Security: DoH protects against DNS spoofing and other DNS-based attacks.
• Censorship Resistance: DoH can help circumvent DNS censorship imposed by governments or networks.

Methods for Configuring DNS over HTTPS on Ubuntu 22.04

There are several ways to enable DoH on Ubuntu 22.04. We'll cover the most common and user-friendly approaches:

1. Using NetworkManager (Recommended for most users)

NetworkManager is the default network management tool in Ubuntu. Many desktop environments integrate with it seamlessly. This method is often the easiest to implement and manage.

1. Open Network Settings: Access your network settings through the system settings menu (usually found by clicking the network icon in the system tray).
2. Edit Connection: Select your active network connection (e.g., Wi-Fi or Ethernet) and click on the gear icon to edit its properties.
3. IPv4 or IPv6 Settings: Navigate to the IPv4 or IPv6 settings (depending on your network configuration).
4. Method: Change the 'Method' to 'Automatic (DHCP) addresses only' or 'Manual' if required.
5. DNS Servers: In the 'DNS servers' section, add the DNS-over-HTTPS address provided by your chosen DoH provider. Examples include:
• Cloudflare: https://cloudflare-dns.com/dns-query
• Google Public DNS: https://dns.google/dns-query
• Quad9: https://dns.quad9.net/dns-query
6. Apply Changes: Save the changes and apply the new settings. Your network connection might briefly disconnect and reconnect.

2. Modifying the `/etc/resolv.conf` file (Advanced users)

This method requires more technical expertise and is generally not recommended for beginners due to the potential for disrupting your network configuration. However, it provides more granular control. Never directly edit this file manually unless you understand the implications.

Instead, use a dedicated DoH client or systemd-resolved which manages this file dynamically.

3. Using systemd-resolved (Recommended for advanced users)

systemd-resolved is a network name resolution service that can handle DoH. This method provides more control and integration with systemd. You would need to configure the `resolv.conf` file using `systemd-resolve` to point to your chosen DoH provider.

Troubleshooting

If you encounter issues after configuring DoH, try the following:

• Verify your DoH provider address: Ensure you've entered the correct address for your chosen DoH service.
• Check your network connection: Confirm that your internet connection is stable and functioning correctly.
• Restart your network service: Use the command sudo systemctl restart NetworkManager or sudo systemctl restart systemd-resolved to restart the relevant service.
• Test your DNS resolution: Use the command nslookup google.com to test if DNS resolution is working correctly.

Conclusion

Implementing DNS over HTTPS on your Ubuntu 22.04 system enhances your online privacy and security. While NetworkManager provides a user-friendly approach, understanding alternative methods like systemd-resolved empowers advanced users with greater control. By following the steps outlined in this guide, you can significantly improve your network's security posture.